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How to plant and grow dahlia tubers

Dahlias are among the lowest maintenance, highest production cut flowers and garden plants you can grow. In a good year, they’ll flower from late June to early December (particularly in a sheltered spot). Dahlias come in all shapes and sizes, and are available in most of the best flower colours. They are some my favourite ever garden plants.

Planting

Soil and Site

Spacing

Dahlias thrive in most sunny situations and do best in a fertile soil, with moisture and good drainage. Dig a hole for each one, at least 30cm square, 30cm deep, spacing for each dahlia tuber 75cm apart (depending on expected final size of variety).

What to do with your bulbs when they arrive

Dahlias are tender tubers. Their root structures look like a bunch of salamis gathered together on a stem. All dahlia tubers will be different sizes. If you plant them out before the frosts are over, they may get frosted and die, so pot them up in March or early April, in a generous pot (at least 2 litre – I use 3 litre pots) filled with multi-purpose potting compost.

Place them in a light, frost-free place and keep the compost moist. They will have formed bushy plants by the time the frosts have ended and will be in flower by the beginning of July. Watch Sarah pot up her dahlia tubers in our quick video.

In the garden

If you don’t have anywhere to grow the potted tubers, you can put them straight into the ground when the frosts are over.

  • Dig a hole 30cm deep by 30cm sqaure, cover the base of the hole with compost or manure and give it a good dousing with a full watering can, then plant the dahlia.
  • On heavy clay, add grit to the planting hole. You will need a stout stake, not just a bamboo cane, to support each plant and it is a good idea to knock this in first and then place the plant by its side.
  • After about a week in the ground, scatter a couple of trowelfuls of GroChar around the clump and give them another good soaking.
  • Once a fortnight, feed them with a liquid balanced feed like Powerfeed Organic Fertiliser. In a drought, it’s a good idea to water them once a week, with a good flood not a gentle sprinkle.
  • With the stake in place at planting, tie them in every couple of weeks. Dahlias grow very quickly once they get going and can easily break off right at the base in wind or rain if they are not securely staked.

For containers

  • Choose a container which is at least 30cm (12″) in diameter and depth for optimum growth.
  • Use multi-purpose compost and add a slow-release fertiliser for strong growth.
  • Plant tubers as deep as you would when planting in the ground.

Keep in mind that all dahlias – even very healthy and long-standing old ones – grow at hugely different rates. Not all dahlias grow quick and fast and often more interesting varieties are slower, more delicate growers. Watch our quick video on growing dahlias in pots.

Aftercare

  • Whether you have raised your dahlias outside in the garden or under cover, you need to pinch out the tips of the main shoot as they grow. Either with a sharp knife, or squeezed between your thumb and forefinger, remove the main shoot down to the top pair of leaves.

  • You also need to remove all but five shoots sprouting from the tuber. There may be several more shoots, some of them weedy, but all but five must go. It feels brutal, but pinching out encourages bushy plants and with only five stems allowed to develop, you will get strong, vigorous growth that will produce lots of flowers.
  • You could choose to grow some of your tubers to take cuttings, and turn one tuber into ten more tubers. Watch and read more about how to take dahlia cuttings…

In recent years, our winters in the South of England have been so mild that dahlias left in the ground, mulched deeply to protect them from the frost, have re-emerged fine, bulking up and flowering well before the other plants grown on in pots. You could opt for this low-maintenance regime, but you risk losing your plants if we are hit by a hard winter. Find out more about overwintering your dahlia tubers in our handy article.

Earwigs can be a problem with dahlias, eating the flowers and the leaves. The organic way of control is to position pots filled with straw upside down raised on canes dotted throughout your dahlias. The earwigs crawl into the straw in the heat of the day. At the end of the day you can bag them, burn them or release them somewhere else far from your dahlias. Slugs also love dahlias, especially when they first shoot, so protect them from the word go.

Cut Flowers

Only pick dahlias in full flower. Recut the hollow stem ends under water to avoid airlocks.

If you don’t pick every flower for the house, it’s a good idea to have an occasional blitz of deadheading. This will make them look much better and will prolong flowering. Cut heads off, removing the whole dead flowering stem.

You may also like:

  • Understanding dahlia groups
  • The history of the dahlia
  • When to plant dahlias

Dahlias are an essential choice for the summer garden. The easy-to-grow tubers will produce a phenomenal display of colour in a range of styles with beautiful dense foliage. Dahlia work perfectly with almost all types of plants, and complement any garden wonderfully regardless of size.

Whether you’re looking to add some vibrancy to your summer, decorate your patio with impressive pot/container displays or grow a ready supply of cut flowers – Dahlias can do it all.

Background

Dahlias are native to Mexico, and the country’s national flower. The Aztecs grew Dahlia tubers as a food crop, and they were widely used there for their nutritional and medicinal properties long before being propagated for their beauty.

It wasn’t until 1789 when the plants were sent to Abbe Antonio José Cavanilles, Director of the Royal Gardens of Madrid, that they got the name we know them by today. Named after the famous 18th Century botanist Anders Dahl, Dahlias were then developed and cultivated to the wide selection of hybrids and varieties we have today – with 42 different species.

Why Choose Dahlias?

  1. They are easy to grow, and suitable for gardeners of all skill levels. They are fast growing by their nature and will flower in the first year and for many years to come (just keep them stored and frost free over the winter).
  2. They are versatile and will tolerate most types of well drained, fertile soil or compost. They can be grown successfully in pots, tubs, window boxes and in borders.
  3. They are one of our favourite summer bulbs because of the many different types/sizes/colours available, which all look slightly different in shape, but are all equal in beauty.
  4. Year after year sees many new exciting new varieties introduced which means once hooked on Dahlias, you will continually be able to find and try something new.
  5. They flower continuously through the summer, right up until the first frost of the autumn.
  6. They look fantastic as cut flowers and are great for lovers of something a little different.

Varieties

The main types of Dahlias available can be classified into a number of different categories, representing the main characteristics of the flower blooms themselves.

Anemone Flowering – Also known as Powder Puff Dahlias, these beauties produce unique flowers with double feathered central petals resembling a Powder Puff.

Cactus – A favourite for many years, Cactus Dahlias produce fully double pointed petals which turn backwards to create a tubular petal effect. Sometimes referred to as Spiky Dahlias, they are perfect for the border.

Dark Leaf – These Dahlias are a little different in that their foliage is not the usual green colours of most varieties. They create an abundance of flowers through the summer as expected, however the blooms appear on darker (usually purple/black) foliage.

Decorative – The largest range of large, fully double flowers with rounded petals through the summer right up until the first frosts. They produce masses of flowers for cutting purposes.

Dwarf Gallery – A range of smaller, more petite Dahlias which are perfect for the front of the border. They are prolific flowering varieties, look also great planted mixed together in pots on the patio.

Dinner Plate – As the name suggests these are the largest flowers within the range, often up to as much as 25cm in diameter (see illustration below). Try these as cut flowers and be certain to draw attention.

Pompom – Love the unusual, then these are certainly for you. Almost spherical flowers (like balls) appear through the summer. The petals have rounded tips and are curved upwards at the edges. The flower heads are also slightly flattened towards the centre.

Dahlia Tubers

All our Dahlias are supplied as top quality dormant tubers which can be planted straight into the place where they are bloom (their final location). Success rate from these dahlia tubers is extremely high and they are a relatively inexpensive way to create a large number of flowers from one tuber.

Dahlia tubers can be planted 10cm deep in fertile well drained soil, outdoors in spring when the frost has disappeared. They prefer to be in a sunny location and spaced at approximately 45cm apart. In areas where there is extreme cold, dig up dahlias and store in a cool peat over the winter. Apply a high potash fertiliser every few weeks in the summer to help growth and they can be dead headed when necessary.

How to grow Dahlia plants in pots or containers

A fantastic way to brighten up your patio is to introduce some Dahlias in pots/containers. The colour range is fantastic, with many unusual bi-colour varieties which will brighten up any space. Simply beautiful to sit back and look at during a warm summer afternoon.

  1. Once your tubers arrive safely in the post, they can be soaked overnight in a bucket of water to soak up as much moisture as possible.
  2. When all signs of frost have passed they are ready to pot up, giving plenty of time to get well established before the summer.
  3. It is recommended to place some pebbles at the bottom of the pots before adding the compost to help with drainage, by ensuring the compost doesn’t block the drainage holes.
  4. Fill in some compost and then add the tuber with the growing tip facing upwards.
  5. Continue to fill in the rest of the compost to firmly hold the tuber, making sure the growing tip at the top is peeping out and is not completely covered. This is now ready to be moved to the patio or garden area, with access to as much sun as possible.
  6. Water well after potting and then keep compost moist but not waterlogged as tubers will rot. You can add a liquid feed weekly during the growing season and provide some protection from slugs as they really love Dahlias.
  7. If growing tall varieties, insert a cane to help with growth and to keep secure.
  8. Little pruning is needed on Dahlias, however you can deadhead as flowers begin to fade.

More Dahlia Tutorials

Dwarf Gallery Dahlias

Cactus Dahlias

Bishop Dahlias

How to Split Dahlia Tubers.

If you’re lucky you live in an area where you don’t have to dig up your Dahlia tubers. For the rest of us we must dig, divide and conquer. How to split Dahlia tubers to keep ’em growing. (even if you live in an area where you don’t have to dig them up you *should* still split your tubers)

Try as I might, despite all of my efforts, I could not kill my dahlia tubers over the winter. I stored them improperly, ignored them and silently cursed them. I’d have given them the evil eye if I believed in that sort of thing but I don’t, so I stuck with a garden variety exorcism.

No luck.

At the beginning of April I opened up my plastic bags of Dahlia tubers expecting to find a wrinkled mass of nothing and found perfectly fine tubers.

I bought and planted these tubers (a LOT of them) for the first time last summer. You can see the mountain of Dahlias 10 or so tubers produced in this post. In the fall, because I live in a cold climate, I dug them up and stored the mammoth things. After one summer in the garden the tubers went from the size of a cute little baby finger to something you could revolve an entire a horror movie around.

I dumped out all the tubers and started looking around the house for containers big enough to plant these Stephen King characters in. It took a while for me to realize that this just couldn’t be how it was done. No one I know who grows Dahlias ever mentioned the need keep 10 or 20 igloo sized pots around for planting the tubers in, in the spring. I must have to DO something with these tubers before planting them again.

Sure enough – I had to split the tubers. And so I did. Some quick research online led me to understand how and when to spit the tubers so now I’ll tell you what I learned.

Clearly I’m not an expert. But the gist of it just involves cutting each finger off and making sure there is at least 1 eye on each of them. If you want a more finessed explanation you’ll have to do your own Googling.

How to Split Dahlia Tubers

STEPS

1. Remove the stringy, withered tubers that will never amount to anything.

See? That’s not going to do anything for you.

2. Once you get all the extraneous stuff trimmed away you can better see what you’re working with.

3. Dahlias sprout from eyes on the very top of the tuber necks. So start cutting off each tuber, making sure to include enough of the neck that you get some eyes.

4. If there are any tubers growing off of other tubers, cut those off and throw them away. Those piggy back tubers will never produce Dahlias. The big main one will, just not its parasitic twin.

If you’re lucky, your Dahlia will have already started to sprout which makes spotting the eyes easy. They’ll have a stem coming out of them. Or they’ll be swollen enough that you can spot them like in the photo below.

For any tubers that didn’t have an obvious eye, I just cut them, taking plenty of neck and hoped for the best.

I told you I wasn’t some sort of Dahlia expert, right? Like, we’ve established that haven’t we? ‘Cause I don’t want you to think I’m posing as some sort of Dahlia expert. Really I’m just a girl with a pair of clippers.

Once you’ve decimated the horror show of tubers, you’ll have several individual, viable tubers for planting this year – all out of that one tuber from last year. This compounds year after year until eventually you have enough Dahlias to start your own free love hippie compound.

Dahlias can seem overwhelming because they do need a bit of work what with having to dig them up, hex them, and replant them every season. They demand attention, you can’t just plant them and forget them. Don’t let their bossiness stop you from growing them though. Divide … and conquer your Dahlias.

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Dahlia Dividing Basics

How Do I Divide My Tubers?:

If you dug and stored your dahlias in the fall, now is the time to check on them to see how the tubers are surviving the winter season.

If you have plump, healthy tuber clumps, you can divide them now or wait until planting time gets closer for dividing. After dividing your dahlias, you want to let them sit out in the cool air for their fresh cuts to dry before putting back away into storage.

If you have clumps that are rotted, it’s probably time to start shopping for some new dahlia tubers for spring. There is no saving a rotten tuber.

If they are shriveled, the humidity is low in the area they are in. If the area has a concrete floor, spray the floor down with water to raise the humidity. There is still time to save them, you can try to spritz them with water and put them back in storage. The best thing in this case, is to leave the clump intact and don’t divide until it gets closer to planting time. That will hold all the available moisture in the clump for now.

Here’s a helpful video from Dahlia Barn owner, Jerry Sherrill, on how to correctly divide your tuber clumps.

How do I know if the tuber has an eye?:

Take a close look at the picture below. The black ‘craters’ or dots, are the eye of the tuber. The eyes are only on the swollen part that is attached to last years stem. If you don’t get a piece of the swollen part, chances are your tuber will not sprout because it won’t have an eye. Unlike potatoes that have eyes all over the tuber, the eyes on a dahlia is only within the swollen part that is attached to last years stem.

Check out our ‘Dahlia Care’ page for more information on dividing your tubers and preparing your soil for spring.

See us at the NW Flower & Garden Show February 7-11, 2018. Plant Market booth 2219.

This year is the garden shows 30th Anniversary. If you’re lucky enough to be within driving distance to Seattle, and want to see thousands of flowers in bloom, shop for plants and bulbs from the best NW growers or want to do a landscape project, it’s the perfect place for inspiration and ideas.

Ripples
Normandy Dee Gee
Maarn
Who Dun It
Jesse G

Hollyhill Candystripe
Gonzo Grape
Coral Mystery
Bahama Mama
A la Mode

Socrates Gladiola
Begonia Baskets
Phlox – Orange Perfection
Peony – Sarah Bernhardt
Bleeding Heart Pink

Dividing Dahlias

Jane Edmanson

JANE EDMANSON: In my mind, Dahlias are the Kewpie Dolls of the flower world – flirty, brazen and joyous. Rich in their variety of colour and shape, they make a great display during summer and autumn.

But this is their winter reality. The flowers have obviously finished. The stems are now dying right back down to ground level and energy is being put into those fleshy underground tubers and now is the time to lift, divide and propagate.

Now you might be surprised just how many tubers are under the ground. A fork is a terrific way to dig them up and you’ll see that some of them have really finished and some are actually really soft and squishy. Well they’re no good at all. They’ve run out of energy, they’ve rotted away. Throw that one away – and the rest of them are nice and hard and if you push into them, you can feel just how hard they are. They look sort of like a lumpy old bit of octopus and some people say that they’re edible, but I think I’d rather eat a potato any day.

The reason that you do lift Dahlia tubers is because if you’re in a frosty area or your soil is very cold and wet over winter, they can easily rot, so you lift them up and that means then that you can divide them and to divide them is really quite easy.

Ok, to separate that one as an individual piece, just use your secateurs and cut as close as you can, without destroying the neck because that’s the area that you’re going to find…down here’s where the buds or the eye is and that’s important – like a potato – you need an eye or two, and they’ll reshoot and that’ll be fine. You can either do it individually or you can put a clump in like that. You don’t have to divide all of them up.

Now to store them, all you need is a polystyrene box or a cardboard box and with a little layer of mulch, just damp not wet, just damp…or you could use sawdust…just lay them down like that and just keep them away from rats and mice too because they like to eat these little tubers and just cover them up and that protects them over winter. Leave it like that for the next 3 or 4 months until you see those eyes shooting and then you’ll find that your dahlias will be absolutely home and hosed – just like that.

Another great garden species the Tree Dahlia. It’s calledDahlia imperialisfor its impressive imperial height. In fact, I’ve brought some in from home and they’re at least 4 to 5 metres high. Lots of people think that the canes of the tree dahlia look just like bamboo, but it’s not. They really have some lovely flowers in autumn and going on into winter. This is a single white one. You can tell it’s just finishing. I’ve got a double white one, there’s beautiful pink and mauve tree dahlias as well and they’re dead easy to propagate from.

Cut the stems and what you’re looking for these little bits here – they’re the nodes or the eyes and that’s the bud that will come out and if you just chop them into pieces. Just use a secateur or whatever you’ve got. Cut them so that you’ve got 2 or 3 different nodes along the bit and each of those bits will grow.

You can either stick them into a pot or into the ground just like that and cover up a couple of the nodes with soil and then those will shoot up or you can do it this way – and this is really easy. Just put them into a pot or a polystyrene box and just cover them up just ever so slightly with some potting mix and you’ll find that each of those…where the node is there – that will shoot up and in spring, you can take those out of the polystyrene box and put them into the garden.

Whether it be the tree type dahlias or the herbaceous types, if you’ve planted these out in spring, you can be assured that your garden will be absolutely flourishing with delicious dahlia colour. Happy growing.

COSTA GEORGIADIS: Covering 18 hectares, this is the largest of the 6 islands on Sydney Harbour and it’s had a really interesting past. The island was used as a prison in settlement days and all the structures on the island were hand built from sandstone by the prisoners. Later on, the island was transformed into the largest ship building yard in the country where they made warships for both World War I and World War II. More on the island later, but now let’s head to Jerry who’s finding out just what it takes for a garden to become a part of Open Gardens Australia.

Dahlias are an outstanding landscape plant with gorgeous summer flowers that can last until late fall. They come in an array of colors and can be very expensive to purchase already leafed out in nurseries.

Dormant Dahlia tubers that have not put out growth for the year can be purchased online and at nurseries and are easy to plant on your own.

Large tubers can be transplanted into the garden two weeks before the last expected frost. Small tubers and seedlings must not be transplanted until two weeks after the last spring frost.

Things you will need: A round pointed shovel. That’s it.

Step 1:

Dig a hole approximately a shovel head wide and a shovel deep.

Step 2:

Remove the Dahlia from the packaging and find the portion of the tuber that should be pointed up with the dormant buds or eyes.

Step 3:

Place the Dahlia tuber in the hole about 6-8 inches deep and cover with soil. Having dug deeper than this add a little soil back in.

Step 4:

Firm the soil with your hands or feet.

Step 5:

Consider spreading some mulch such as wood chips or bark over the disturbed soil to help keep down weeds and reduce watering needs in the summer. You’re set to go. You will see new growth emerging from the soil in late summer.

About the Author:

Jonathan Aflatooni is exceptionally passionate about plants and landscaping. Since a young age his Mom gave him the gift of working with plants and landscapes and it grew on him ever since. Along with his brothers they own and operate a landscape maintenance and installation company called Blacklotus Landscaping LLC and have been in business for over 5 years now. Hope to share some more practical advice and insights with everyone in the near future.

When To Plant Dahlias

Dahlias are some of the lowest maintenance, highest production cut flowers and garden plants you can grow.

Here we share our tips on when to plant dahlias and other good to know information.

When to plant your dahlia tubers

Dahlias are tender tubers so they need to be started off under cover in early Spring, then planted out after the frosts. If you plant them out before the frosts are over, they may get frosted and die, so pot them up in March or early April.

To get them started half-fill a 3 litre pot with peat free multipurpose compost and place the tuber in the pot with the central stem upwards and cover with more compost. Don’t forget to label and water the pot, place is a nice warm spot, frost-free, so it can receive some warmth and light.

After 2-3 weeks shoots will start appearing – some varieties may take a little longer, but as these shoots grow pinch out the tips of the main shoot (you can use a sharp knife or a squeeze between your thumb and forefinger), down to the top pair of leaves.

Then, as the plant starts to grow remove all but five shoots sprouting from the tuber. It will feel harsh but by having only five stems, this will allow each stem to develop, grow strong and vigorous, resulting in lots of flowers!

Your dahlia tuber will then flower from June to early December (particularly in a sheltered spot).

They come in all different shapes and sizes, as well as some of the greatest colours, shop our collections today.

If you need further advice, simply watch Sarah’s video below on how to plant dahlia tubers , or visit our step-by-step guide here

Tender Dahlia Plants – Are Dahlia Flowers Annual Or Perennial

Are dahlia flowers annual or perennial? The flamboyant bloomers are classified as tender perennials, which means they may be annual or perennial, depending on your plant hardiness zone. Can dahlias be grown as perennials? The answer, again, depends on your climate. Read on to find out the real story.

Can Dahlias Be Grown as Perennials?

Perennials are plants that live for at least three years, while tender perennials won’t survive cold winters. Tender dahlia plants are actually tropical plants and they are perennial only if you live in USDA plant hardiness zone 8 or higher. If your hardiness zone is 7 or below, you have a choice: either grow dahlias as annuals or dig the tubers and store them until spring.

Growing Dahlias Year Round

In order to get the most of your dahlias, you’ll need to determine your hardiness zone. Once you know which zone you’re in, the following tips will help in growing or keeping these plants healthy and happy each year.

  • Zone 10 and above – If you live in zone 10 or above, you can grow dahlia plants as perennials. The plants require no winter protection.
  • Zone 8 and 9 – Watch for foliage to die back after the first killing frost in autumn. At this point, you can safely cut the dead foliage to 2 to 4 inches above the ground. Protect the tubers by covering the ground with at least 3 or 4 inches of bark chips, pine needles, straw or other mulch.
  • Zone 7 and below – Trim the dahlia plant to a height of 2 to 4 inches after frost has nipped and darkened the foliage. Dig clumps of tubers carefully with a spade or garden fork, then spread then in a single layer in a shady, frost-free location. Allow the tubers to dry for a few days, then brush off loose soil and trim the stems to about 2 inches. Store the tubers in a basket, paper bag or cardboard box filled with moist sand, sawdust, peat moss or vermiculite. (Never store the tubers in plastic, as they will rot.) Place the container in a cool, dry room where temperatures are consistently between 40 and 50 F. (4-10 C.).

Check the tubers occasionally throughout the winter months and mist them lightly if they begin to look shriveled. If any of the tubers develop soft spots or begin to rot, cut off the damaged area to prevent the rot from spreading to other tubers.

Note: Zone 7 tends to be a borderline zone when it comes to overwintering dahlias. If you live in zone 7b, dahlias may survive the winter with a very thick layer of mulch.

Are Dahlias a Perennial Flower?

Arthur Tilley/Creatas/Getty Images

Perennials are plants that grow, bloom and die back at the end of the season, returning the following season to go through the whole process again. Dahlias may be considered perennials, but there are a few differences between dahlias and the usual garden perennials.

Bulbs

Bulbs also return year after year but they are classified separately because of their root structure. They are often grown in separate beds because their care requirements are different from those of other perennials.

Tubers

Although dahlias are often classified and sold as bulbs, they are actually tubers. Tubers are swollen root structures with no buds or eyes. Whether you call them bulbs or tubers, dahlias are planted and maintained like summer bulbs.

Tender Plants

Dahlia tubers are tender and will only survive winter temperatures in U.S. Department of Agriculture zones 9 and warmer. In cooler zones, they must be dug up, cleaned off and stored in a frost-free location, then replanted the following season.

Why dahlias are a perennial favourite in the garden

Reuters A dahlia in one of its many forms and colours.

I’m in love with dahlias.

Who wouldn’t be, with their flamboyant blooms and strong stems that are a perennial favourite amongst cut flower growers.

They come in just about every colour and form imaginable – from elegant to exotic-looking, from shaggy to saucer shaped, and fimbriated (where the tips of the ray florets split evenly into two or more divisions) to single orchid (a whirligig look, where the sides of the florets curl inwards or outwards), among others.
Whatever your taste, there is a dahlia to suit any garden – and they are a snip to grow.
And now is the time to plant them, October being one of the best months to set them out, as the risk of frost should, by now, have passed.
They require nothing much – just an open, sunny position with a little shelter from wind and a compost-enriched soil that is free-draining. You don’t want the ground to be too rich at the beginning or you might inherit soft, sappy growth that breaks easily and attracts diseases. Dig in some compost, definitely, but avoid fresh manure.

Fairfax NZ Examples of prize-winning dahlias – “Embrace” (yellow) and “Roke Wood”.

If you have left your dahlia tubers in the ground for a couple of years, they may benefit from lifting and separating. This is not hard to do but there are a couple of things to look out for.

When you lift a clump of dahlia tubers and clean off the soil, you will notice several tubers coming off the main stem. Any tubers that grow off those tubers (that don’t come directly off the stem) should be discarded as they won’t develop eyes for growth.

Discard them, then divide each remaining tuber using a sharp knife. You must ensure each tuber has an eye, much like you see on potatoes. These are found right up the top on the neck of the tuber (the part that attaches to the stem). New shoots will eventually sprout from these eyes.

Fairfax NZ The “Ruskin Andrea” variety.

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Plant your dahlia tubers so that their necks are 5-6cm below the soil. If tubers have already sprouted, position them so the base of the shoot is just below soil level.

Give them a reasonable amount of room, about 60cm space between each plant, though if you are growing the very large decorative times, you may need to give them more room. These can and do grow a considerable height and width. Mine typically reach 2 metres high. Insert stakes at planting time and scatter some slug and snail bait around the base of your plants, as when the shoots appear, so too will these slimy pests.

Andrew Gorrie A dahlia tuber and seeds.

At planting time, dig in a balanced fertiliser or apply blood and bone. Later on, switch to a high-potassium fertiliser (a tomato fertiliser is good) and feed regularly to promote good flowering.

Pinching off the tops of your dahlias when they reach 30-40cm tall encourages them to branch out produce more flowers. Simply remove the central shoot just above a pair a set of leaves.

Water your dahlias well during growth, especially during dry spells and when flowering. Apply a mulch in summer to help conserve moisture in the soil and prevent weeds. Since their feeder roots are near the surface of the soil, dahlias do not like competition from weeds.

A note though: when first planting out your tubers, hold back on the water until you see the first shoots. Tubers rot easily before they produce shoots and roots.

If leaves have yellow speckles on them then wither to brown, your dahlias may be infested with spider mites, which make their home on the underside of leaves. They are hard to spot because they are microscopic in size, but you may see a web on the leaves or flowers.

The minute you see signs of spider mites, take action, as a single mature spider mite can lay thousands of eggs in a month. For small infestations, remove infected leaves. A regular blast of water also discourages them, as they like dry conditions. Or spray every 10 days with a miticide.

When picking for the vase, cut the stems just above a leaf axil, as a new flower will grow from here. Pick when the flowers are three-quarters to fully open, as they won’t open when cut in bud. Have a bucket of warm water on hand and put your cut stems immediately in the bucket.Your dahlias should last 5-7 days in the vase.

Visit Jane’s blogs sweetlivingmagazine.co.nz and flamingpetal.co.nz.

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This morning I woke up, put the kettle on and wandered outside to see if the milk had been delivered, which means going down the garden path. As I tried not to slip on the frosty flags, I felt the presence of something in the sky behind me, turned and saw a peregrine falcon flying over the house, beating bent-backed scimitar wings in that idiosyncratic muscular, direct manner. If you know anything at all about birds there are certain rules that always apply. One of them is that if there is any doubt then it isn’t. When you see the real thing you know. If you are unsure whether it is a buzzard or golden eagle then it is always a buzzard. So it is, in this part of the world at least, with peregrines. You see them with a thump of shocking recognition. So, for a breathless minute, one of the fiercest and most feral of creatures on the planet beat straight above my primped garden and, until it had disappeared into a dancing mote in my eye, we alone shared the tentative dawn sky, the carefully edged path, the clipped yews, the family sleeping indoors, the everything known and unknown of that minute. Then it is gone and with the pang of loss a great flush of experience and excitement that lights up the rest of the day on into memory, and, if you have any shred of wonder about you, for the rest of your life. The milk, by the way, had not arrived.

Now, back to business. Part three of my bulbous mini-series. Having wended through snowdrops, daffodils, tulips, alliums, lilies, crocosmia, et al, we arrive, panting a little, at autumn and, crucially, dahlias.

I have written before on these pages on how dahlias were locked into my mindset as cut flowers of the Fifties, grown by my mother in a border down by the chicken run dedicated year on year to them and gladioli, the combination looking in full flower like a tea cosy knitted from all the scraps of wool left over from Christmas-present jumpers. I could not accommodate this in any kind of reality and did not grow either for 30-odd years, but having exorcised my demons with flowers I am back in love with dahlias and glads and would not be without them.

Dahlias are tubers – and like potatoes were originally imported from their native Mexico as potential food – and do best in a rich soil with plenty of added organic material so the tubers can swell. As with all bulbous plants, the bigger the bulb, corm, tuber or rhizome, the better the flowers are likely to be. They are best planted reasonably deep, although if they are to be lifted then 6-9in is deep enough. If they are to be permanent then double that.

Dahlias are not hardy and the first proper frost will reduce the flowers and foliage to blackened rags, but it is a mistake to lift them before the first frost as the tubers go on growing and swelling right up to that frozen moment. But if you are likely to get any sustained frost below -5C, or any late-spring frosts – and that includes me and most people north of Oxford – then it is best to dig the tubers up, dry them and then store them in damp, used potting compost in a frost-free dark place. Replant them in April, mulching them well. By the time the new growth works through the layers of soil and mulch, the frosts should have passed and the roots will be working well into the soil. If you want late flowers, cut the initial new growth back in early June to 12in or less, and they will flower all the better for it in September and October.

Like dahlias, gladioli can come in a range of Fifties’ lipstick pinks, pastel yellows, mauves, lilacs, oranges and other hues of that ilk. But it is wrong to brand them with that palette because there are wonderful rich colours, too, especially in the species gladioli (of which there are nearly 200) like Gladiolus byzantinus, G cardinalis, the white with deep interior markings of G callianthus and some of the florists’ varieties like ‘Firestorm’, ‘Fidelio’, ‘Black Beauty’, or the green ‘Spring Green’ which exactly fits what my American friends would call ‘chartroose’. Most are tender and are best dug up each winter along with the dahlias. But unlike dahlias, which, especially if deadheaded regularly, should flower from August to November, gladioli only flower for a couple of weeks so it is a good idea to plant a handful of the (surprisingly small) corms every couple of weeks from Easter to Whitsun to maintain succession of flower.

More recognisable as ‘bulbs’ are the autumn crocus and colchicums that start to appear from September. Colchicums look like crocus but are members of the lily family. Autumn crocus look a bit like colchicums but are members of the iris family. Confused? Stay with it. The easiest way to distinguish them is to count the stamens: colchicums have six whereas crocus have only three. Autumn crocus are smaller and neater than colchicums, growing to 2-4in, and many of them have very narrow, grass-like leaves that appear at the same time as the flowers. All colchicums are naked, but in a baby birdish, toadstoolish sort of way rather than lovely and nude. They do have leaves – good ones with a spread of up to 18in – but they do not appear at the same time as the flowers, appearing in spring and dying back in summer before the flowers appear in September.

Grown in grass its nakedness is hidden and, perhaps more importantly, supported. Colchicums grown in bare soil beneath a tree or shrub are easily and irretrievably bashed by wind and rain. Although the grassland can be damp in winter, it must be dry in summer while the corms are dormant and as open to full sun as possible, although they are often found in woodland so perhaps some dappled shade suits them well so long as it is dry. They should also be planted deep – with at least 4in of soil over the top of them.

Most autumn crocus are suitable for a container or rockery where they can be seen as miniature, jewel-like flowers, but some can be grown against a larger canvas. Crocus speciosus, and C nudiflorus, are the easiest to naturalise and fit in well with a basic haymaking regime – namely grass that is left long until midsummer, cut and raked, cut again at the end of August just before the crocus appear so the flowers will stand proud of the grass, and then cut back again in autumn.

The only frost-hardy nerine is Nerine bowdenii and it is glamorous, long-lasting, and … well, to my eye at least, without charm. It is the pink I think. But should you wish to grow them for their undoubtedly dramatic and long-lasting autumnal display, the bulbs should be planted very shallowly although, in cold areas at least, just covered by soil. They need a really good summer baking to flower, so the base of a south-facing wall or in pots left in full sun would be ideal. If they stop flowering, dig them up, tease the bulbs apart and replant with some space between them.

Secret tips to growing showstopping dahlias

What is it about dahlias that generates such passion in gardeners?

“Their diversity and the way they make people smile,” explains Robert Papp, president of the South Coast Dahlia Society. “There’s always something for everybody.”

Look for Papp’s blooms at the South Coast Dahlia Show Aug. 16-17 at the South Coast Botanic Garden in Palos Verdes. The show will feature a variety of categories for competition. And an added bonus for dahlia lovers: The colorful cut flowers will be given away at the end of the show.

Papp shares some insight, tips and secrets on the popular blooms.

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For the uninitiated, what is it about dahlias that endears them to gardeners and plant lovers alike?

There are 20 different forms of dahlias and 10 different sizes. As far as colors go, they can be solid, blends, bicolor and variegated. There are no black or blue dahlias. There are shades of lavender that look blue and shades of purple that look black. There are 7,615 classes. The one I like the best is Show ‘N’ Tell, a large red and yellow flower with split tips. It grows up to 10 inches. It’s a showstopper.

Water is such an issue. Do dahlias require much water?

Dahlias like a deep water. I soak mine twice a week. The two death knells for dahlias are too much water, which will rot the tubers, and cold. You don’t want to hand water them. That way, you only get water a couple of inches down and that’s not where the roots are. I use a drip irrigation system. It saves most of the water. The soil is the most important thing. Dahlias like a slightly acidic soil, so I’m intent on my soil being organic. Good soil will retain water. I’m also big on vermicomposting. I make worm compost tea and use it for a drench and spray the foliage with it.

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Dahlias can grow quite tall. Is staking a must?

You don’t have to stake a 4-foot plant. But you have to stake the larger blooms. I like to use a 10-foot conduit cut in half. It’s very cheap and very sturdy. I also use tomato baskets and put them over the tubers. Just keep tying them as they grow.

Where is the best place to find dahlias?

Check out www.dahlia.org, the American Dahlia Society website. It provides a list of commercial growers. I suggest buying locally. I don’t like buying them at hardware stores. You’re buying a pretty picture. Dahlias come in three categories: show growers, garden variety and cut flower variety. Go shopping at shows and write down what you like.

Any trade secrets?

Even though I live close to the ocean, I have to place a sunscreen over my plants. Come show time, I put umbrellas over them. They can’t take full sun full time. They prefer morning sun with a partial shade in the afternoon. Also, I recommend Azomite, a rock dust that adds nutrients to the plant.

Follow me on Twitter: @lisaboone19

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How To Grow Dahlias
With A Brief Introduction
To Their Origin
Dahlias have an interesting history.
The first tubers arrived in Europe at the end of the 18th century, sent over to Madrid by the Spanish settlers in Mexico.
Andreas Dahl (after who the plant is named) regarded it as a vegetable rather than a garden flower, but interest switched from the edible tubers to the blooms when the first varieties with large, double flowers were bred in Belgium in 1815.
Within a few years nearly every colour we now admire had been introduced and Victorian catalogues listed hundreds of varieties.
The favourites in those days were the Ball and Small Decorative Dahlias.
Today it is the Large Decorative and Cactus varieties which capture the public fancy. Fashions change but the popularity of this late summer flower continues to increase.
The reasons for this devotion to the Dahlia are fairly obvious. First of all the skill of the breeders in America, Australia, Germany, Holland, and England has produced a range of sizes and colours unmatched in the world of garden flowers.
Plants ranging from dwarf bedding (twelve inches high) to giants taller than a man. Flowers range in size from an inch to the largest dinner plate.
Equally important is the time of flowering.
From the end of July to the first frosts, Dahlias provide large amounts of colour when so many flowers are past their best.
Above all the Dahlia is an accommodating plant.
It likes a good loam, but will grow almost anywhere. It relishes sunshine, but can still do well in partial shade.
A bed just for Dahlias is really the ideal way of growing them, but they are quite at home in the herbaceous border or even the rockery for dwarf bedding varieties.
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WHERE TO PLANT DAHLIA TUBERS

Dahlias will grow in almost any location and in almost any soil.
However, to have outstanding plants and flowers, you must be selective of the planting placement.
Dahlia roots, (tubers), need a sunny location in order to thrive. They should receive at least a half-day of sun and even more is preferable.
Select a site for your dahlia garden that is away from trees, sunny, and yet sheltered from direct wind.
Dahlia tubers are surface feeders.
Since they don’t send down a tap root or long feeder roots the plants will easily be blown over by the wind.
Staking the plants is essential and will be covered later with planting instructions.
A further important consideration is the condition of the soil.
In most cases, a good everyday garden soil is adequate.
But good soil drainage is vital for dahlia plants.
If the soil holds surface water for more than several hours after a rain, the likelihood is that it should be augmented with organic matter.
Humus, peat moss, sand, or well-rotted manure will work well. A mixture of equal parts of all of the above makes an excellent addition to heavy soil.

HOW TO PREPARE THE DAHLIA GARDEN SOIL

If at all possible, choose the planting site in the autumn.
Dig or till your plot and start working in compost, peat moss, sand, and rotted manure. Keep the site as weed free as possible during the winter months.
This will make your spring work and planting much easier.
Then as spring comes, the area will need a further digging, or tilling to a depth of at least six inches but eight to ten inches is better.

If you choose to use a commercial fertiliser, be sure to keep the nitrogen (the first of the three content numbers) to a low number.
For example, a 5-20-20 would be adequate.
This of course should be well worked into the area in a ratio of 3 to 5 pounds per 100 square feet.
Further fertilisation should not be needed although some people apply a second mid-season application of the above formula to their dahlias or use a similar ratio in a liquid form.

HOW TO STORE DAHLIA TUBERS

The storage of dahlia tubers prior to planting is critical. Tubers must not be allowed to freeze or to be placed in a room that is heated above 50 degrees F. A temperature of around 40 degrees F is preferred. The tubers must be stored in a dark location, high in humidity.
We store the tubers in a concrete built building in racks to leave an air flow around the racks
Continue to check your dahlia roots (tubers) weekly for rot or mould.
As you handle the dahlia tubers be careful not to damage the growing point known as an ‘eye’.
Remember, that is your future plant.

WHEN TO PLANT DAHLIA TUBERS

The dahlia tuber is unlike many other bulbs in that it wants to be planted in warm soil compared to say, tulips.
A rule of thumb for planting time is: plant dahlias when you would plant other root type vegetables such as carrots.
In other words, spring should be well on its way with the longer and warmer days.

PLANNING A DAHLIA GARDEN

Now that the area for planting your dahlia tubers is well prepared and your stock of tubers is in hand, it is time to prepare a garden layout plan.
Because certain varieties grow considerably taller than others, you should plot where you want tall plants and where the shorter than average should go.
Also, if colour mass is important, then get these details laid out before you actually begin to plant.
Many commercial dahlia suppliers indicate the approximate height of the plants in their catalogues.
Using this information can be a help in formulating your layout plans.

The layout plan will also need to take into account the number of varieties that you plan to plant.
The average planting space between plants is 18 to 24 inches, especially for the large flowering varieties.
The shorter varieties can be planted closer together, but remember, when you dig those clumps in the autumn, you definitely don’t want them intertwined with their neighbour.
Plan for the rows to be three to five feet apart, depending on the size of the plant.
When the rows are two to three feet apart, the plants will generally grow taller as they ‘reach’ for light and your access up and down the rows becomes more difficult.
Close planting also shuts down air circulation to the lower leaves, encouraging powdery mildew.
If you plan to use a hand tiller between the rows, then plan your rows according to its width and be sure to leave extra width so as not to till too close to the plants and damage those new tubers.

TIPS FOR PLANTING THE DAHLIA TUBERS

Prepared holes for planting should be 5 to 6 inches deep.
If you plan to stake the plants, NOW is the time to do this and not later when you may damage the tuber by running a stake through it.
Pound a sturdy stake, 4 – 5 feet tall into the ground beside the tuber hole.
Some have found tomato cages to be satisfactory in supporting the plants, but these too have wire spears and so they should be put in place when you can see exactly where the tuber is to be located.
Tomato cages are generally only satisfactory for the smaller plants. With the stake or tomato cage in place and a planting hole on one or both sides of the stake, place the tuber in the hole laying longwise on its side, with the sprout or eye facing up.
If the tuber has a sprout an inch long or more, care should be given not to damage the fragile shoot.
However, if this does happen, and it is very easily done, then don’t despair, there are auxiliary eyes at the base of the broken shoot and they will grow, but you will have lost some advanced growth in your future plant.
Do not add fertiliser to the hole as this may damage the new tender root system.
Cover the tuber with 4-5 inches of dirt. Some gardeners have found it helpful to hill the plants as they grow to provide support to the stems, but often this is not adequate in wind prone areas.
Tie a name-tag on your stake so you will know later which plant is growing there.

HOW TO WATER DAHLIAS

Unless it is a very dry spring, it should not be necessary to water at the time of planting. The tubers will begin growing with the warmth and moisture in the soil.
It is vital that they form a root system early in their planted life to assure a strong and healthy plant.
Watering at the time of planting may encourage rot causing you to wonder why that prized variety is not growing.
When you carefully investigate the problem, you may not even be able to find the tuber or you will find a lump of rotten muck.
Not a pretty sight!
Once the plant begins to grow you can begin to water every few days.
Watering will be necessary in most areas throughout the summer months.
Water dahlias at the root level using a drip system.
Deep watering, or in other words, a good soaking is better than passing a spray on the plants for a short period.
In fact, it is much preferred in order to prevent disease on the foliage and to conserve water.
Many growers find the soaker hose in its various forms to be the best and then the water goes in the soil where the plant needs it.

HOW TO FIGHT DAHLIA PESTS

Once the shoot is above the soil surface, the first slug within a city block will ‘smell’ it. Be prepared!! Get out that slug bait and spread it liberally everywhere, or the slimy pests will devour every tender morsel for lunch! You may have other methods of taking care of these hungry critters, but I have found the slug pellets to be my favourite as I can broadcast them over an area very quickly and in most cases with good results.

MORE DAHLIA GROWING AND PLANTING HELP

Now that you have gone to all that work, you will want to care for your plants and see them produce beautiful prize-winning blooms.
Keep the area weed free, or at least as much as your back will tolerate.
Also remove any broken or damaged foliage.
Good air circulation, especially near the ground is needed by the plants to prevent powdery mildew.
Once the plants are several feet high the lower leaves can be removed to increase air circulation.

TYING DAHLIA PLANTS TO THE STAKES

When the plants get to be a foot tall, be sure to begin tying them to the stakes.
A wind will lay your plants flat from here on and may even break the stalk from the tuber. (Then you will be sad!) You will need to continue to tie them to the stake every 18 to 24 inches.
If you grow 4 or more plants of one variety, you may find it easy to run garden twine the full length of the row.
This can easily be done down each side of the plants using the existing name stakes.
The twine should be spaced every 8 – 10 ” up the stake and can be secured on the stakes just with a single wrap around each stake as you go down each side of the row.
This fast method works well until your partner snips the string while cutting a bouquet of flowers.
Amber Festival And Gateshead Festival
Disbudding Dahlias

Blooms are generally cut just above a node. In the picture on the right, two side buds were removed from the first node below the central bud.
The next node down has two laterals (sometimes two buds instead of two laterals) and two leaves.
In the picture, the distance from the bud to just above the second node is about three inches.
By the time the bud matures into a full bloom, that distance may be estimated at 9 to 12 inches–not really long enough to ensure good placement in a competition type vase.
Therefore, the two laterals at the second node would be carefully removed–do not remove or injure the leaves.
Later the bloom would be cut just above the third node and the stem would be 18 to 20 inches long.
Alternatively, if the distance from the bloom to just above the second node was estimated to be 15 to 20 inches, the two laterals at the second node would be retained and the bloom stem would be cut just above the second node.
The picture on the right is a similar view of another plant.
It is presented in the hopes that one of the two pictures will be helpful in understanding disbudding and removing laterals.
The second question is:

If it is desired that the plant be taller than the average, do not remove any more laterals than is required to get the desired stem length.
If a shorter plant is desired, remove the laterals at the next node down.
Some people remove laterals two and three nodes below the node where the side buds were removed.
In the picture, the laterals at the second node are currently about waist high.
They will grow considerably.
A little imagination suggests that leaving the laterals at the second node would eventually result in a very tall plant.

In some cases, there will be three small buds and one large bud at the tip of a lateral.
When this occurs, the third bud will be attached to the stem of the central bud together with a small leaf.
The 1st and 2nd side buds will be in their usual place on their respective stems. When the buds are first visible, all four are firmly packed together and hard to differentiate.
All three of the smaller buds should be removed.

If a plant is not disbudded, all the buds will develop.
The picture on the right shows a central bud and two side buds whose stems are lengthening.
Eventually, the stems will be 6 to 10 inches long and all three buds will bloom. The three blooms will be approximately the same size but smaller than the central bloom would be if the two side buds were removed.
Ideally, when the blossom is mature, the length of the stem of the central bud should be 1 and 1/2 times the diameter of the bloom.
Technically, the removal of the side buds and the third small bud, if it exists, constitutes disbudding.
However, in practice the activity of disbudding also includes removing some laterals.

When the small side buds have been removed, two questions need to be asked and acted upon when answered.
First question is:

Will the stem for this bloom be long enough for the purpose it is to be used ? Do we want this plant to be on the tall side, the short side, or medium height for its type?

Removing laterals is an art not a science.
The beginner is advised to disbud and remove the laterals at the next node down if they are laterals.
If the growth at that node appears to be additional buds, they should be removed. Beginners will not be beginners for long.
They will very quickly develop their own disbudding and lateral removing strategies once they see the results.
GOOD LUCK WITH YOUR DAHLIA GROWING: J R GOTT

Hope this small piece of information
has been of some help to all you Dahlia lovers
If so let me know
at
< [email protected] >

This Is The How To Grow Dahlias Page Of
< www.jrg-dahlias.co.uk >
For more on Dahlias go to < www.anglo-dutch-dahlias.co.uk >

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