If you still have unplanted spring bulbs, it’s better to get them in the ground. Some bulbs, such as tulips, will perform well even if planted late. See our handy spring bulb chart with hardiness zones, depth, and spacing for all your fall-planted bulbs.
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When to Plant Bulbs
Spring-flowering bulbs are planted in the fall to give them ample time to grow roots during winter in preparation for the spring show. So, if you think that autumn’s the time to stop gardening, think again! Fall will be bulb-planting time! It’s so easy to stick bulbs in the ground—and so magical to see their colorful blooms energe in early spring to lift your spirits.
Planting time is usually late September to mid-October in northern climate so that bulbs can grow roots before the ground freezes. (Tulips are one exception–you can plant these as late as you can get them into the soil.) Consult our Frost Dates Calculator to see when the first fall frost will be in your area.
In the lower South, where you may not have a hard freeze, early November is a good time to plant. You can plant them as late as December but the later you wait, the less able the bulbs will be to establish themselves.
How to Grow Bulbs Chart
See the chart below for type of bulbs that you plant in the fall for spring bloom.
In the warmer South, you may need to pre-cool some bulbs. Most spring-flowering bulbs require a 12 to 16 week cold period in ventilated packages in the bottom of your refrigerator at 40 to 50 degrees F. before planting. Check with your bulb supplier to determine whether the bulbs you purchase have been pre-cooled or whether you may need to give them a cold treatment.
Also, in warmer climates, note that some bulbs will only bloom once and then they’re done for the season. For example, you will have to plant tulip bulbs again each year. Still, they are a beautiful sight to behold and well worth the effort! Other fall bulbs, such as daffodils, will act as perennials and come up year after year.
Bulbs can be ordered from a mail-order catalog ahead of time, so that the bulbs arrive right in time for fall planting. Or, make sure you buy your bulbs from a reputable nursery or garden center. Remember, second-rate bulbs produce second-rate flowers, don’t sprout at all, and often don’t return year after year. Don’t forget to plant extra for cutting so you can bring some of that spring color indoors.
Good bulbs should be fresh and firm, not brittle or rotted or moldy. Also, choose bulbs with intact husks to better fight any disease.
When you receive bulbs, plant immediately or store in a cool, dark, dry place at around 60 to 65 degrees F. Temperatures above 70 degrees F. may damage the flower buds.
Selecting Bulb Varieties
Here are some of the most popular spring-blooming bulbs planted in the fall.
- Daffodils are a favorite because they are vole- and deer-resistant.
- Jonquils have tiny blooms and naturalize. They’re one of the first flowers to bloom—and look especially lovely when planted in a grove or field together.
- Crocus are a spring-flowering favorite, and come in a range of colors.
- Snowdrop (Galanthus) are little white bells that bloom in early spring.
- Hyacinth (including grape hyacinths) are small blue clusters of tiny bell-shaped blooms which are good for naturalizing.
- Tulips looks beautiful when planted en masse and bloom after the daffodils. They look great paired with grape hyacinth.
- Irises are hardy, reliable, and easy to grow, attracting butterflies and hummingbirds and making lovely cut flowers.
- Gladiolus have tall beautiful spikes and tend to bloom in late spring to mid-summer, depending on the variety.
Bulb Planting Tips
- Select a site where the bulbs will receive at least part sun throughout the spring.
- Bulbs will need soil that drains nicely or they will rot. Work a few inches of compost or organic matter into the soil before planting for nutrients and drainage, especially if you have heavy clay soils.
- Bulbs look great planted en mass—in a grove, near the mailbox, as swaths of colors in garden beds, and as colorful borders.
- In general, plant bulbs at a depth of three times the width of the bulb. (That means about 4 to 6 inches deep for small bulbs like snowdrops, crocuses, and grape hyacinths, and about 8 inches deep for large bulbs like hybrid tulips, daffodils, and hyacinths.)
- You can use a bulb-planting tool but if you are planting en masse by the dozens, just use a shovel and make a wide hole for planting many bulbs at once.
- Place shorter bulbs in the front of beds and borders.
- Plant bulbs generously in case some do not sprout. And plant them in random order and spacing for a more natural appearance. If you love groves of daffodils and blanketed landscapes of tulips, be prepared to buy and plant a large quantity of bulbs!
- After planting, apply fertilizer low in nitrogen, such as a 9-6-6 formulation. If your soil is sandy, plant bulbs slightly deeper; in clay soils, slightly shallower.
- Water well after planting.
- Apply mulch to the planting area to keep the weeds down, hold in moisture, and avoid heaving from wintertime thawing and freezing.
- Do you have voles or squirrels? Consider planting your bulbs in a “cage” fashioned with chicken wire. Also, check out our tips for preventing vole damage and squirrel damage. Or try planting some rodent-proof bulbs.
- Consider bloom time for each bulb (early spring, mid-spring, late spring) so you have blooms throughout spring!
Now that you’ve mastered the art of the fall bulb, check out our page on how to grow spring-planted bulbs!
Latin for garlic, Allium, the Flowering Onions, are available in diverse heights and sizes, are rabbit-, rodent- and deer-resistant, and are seldom affected by disease. Adored by bees, butterflies and pollinators, Allium extend the spring flowering season with bold, dramatic color and center-stage, statuesque garden architecture, or lush, delicate clusters of florets that gracefully adorn garden borders. Gleeful bees happily bumble from Allium floret to floret in grateful awe of their floral largesse. Allium are also valuable as cut and dried flowers.
Most varieties of the globe-shaped Allium have an incredibly long garden presence. The stalks emerge from strappy, low-growing foliage, the thick cigar-like buds form and a spidery outline of the globe develops as up to hundreds of star-shaped florets burst into bloom with delicate filament-like stamens. As the flowers die back after weeks of powerful presence, the dried seed pod form of the globe remains, like a hauntingly beautiful garden sentry.
There is nothing better after the brilliant opening act of Narcissi and Tulips than to anticipate the stunning second act of Allium, Brodiaea, Camassia, Eremurus, Herbaceous Iris, Dutch Iris and soon thereafter, Herbaceous Peonies. (You may also want to experiment with Gladiolus communis ssp. byzantinus, Ixiolirion tataricum ssp. pallasii, Ornithogalum ponticum Sochii and Oxalis adenophylla.) Soon thereafter, one can look forward to the opulent finishing act of Lilies.
If you are looking for heirloom flower bulbs, you’ve hit the jackpot with Allium. There are few flower bulbs native to the U.S., but A. amplectens Graceful Beauty is one of them.
1857 A. amplectens Graceful Beauty (American)
1800 A. atropurpureum
1830 A. azureum
1800 A. caesium
1884 A. christophii
1823 A. cowanii
1876 A. karataviense
1823 A. neapolitanum
1762 A. nigrum
1873 A. oreophilum
1896 A. schubertii
1873 A. siculum bulgaricum
1594 A. sphaerocephalon
1873 A. unifolium
Horticultural Zone Hardiness
Each variety of Allium has its own hardiness zone requirements that should be considered when selecting varieties for your garden. If your garden is in a horticultural zone that is either too cold or only marginally appropriate, you may want to apply no more than a 2″ layer of mulch after the ground surface freezes in the fall. The mulch should trap the cool temperatures into the soil, not warmth. Mulch helps to protect the bulbs from arctic temperature spikes. Good mulching mediums include straw, salt marsh hay or oak leaves. In the spring, you can loosen the mulch in the area in which the Allium will be sprouting.
Check your shipment against the packing slip and make sure that everything is as it should be. Occasionally, bags of smaller bulbs may be placed in the inner boxes of other bulbs to reduce jostling during shipment. If you can’t find something, open all of the inner boxes. If there is a discrepancy, please call us immediately so that we may resolve it with you. Since every bag or box of bulbs in your order has been scanned using its UPC barcode, we can usually tell you in which box each variety is located.
Inspect your bulbs carefully. We make every effort to ship you only healthy, firm, top quality bulbs.
Allium bulbs look different from other types of flower bulbs like Tulips or Narcissi. It is natural for some types of bulbs to develop a transportation mold when they are exposed to oxygen. It is a natural gray-blue-green mold that occurs when they are exposed to air, and that disappears as soon as the bulbs are planted. The soil naturally wicks it away. If you prefer, you may spread the bulbs out in the sun, or brush it off with a paper towel although it is not necessary.
Little cuts, scars, discolored exteriors and dimples are normal marks from the flower bulb harvesting, cleaning and sizing processes in the Netherlands. Some bulbs may have a fully intact, papery skin while others have partial skins, and others may be skinless. The existence or condition of the skin has nothing to do with the performance of the bulb. The most important factor is the way that the bulb feels. As long as the bulb is firm, it is a good and viable bulb. Some bulbs may already have tiny baby bulbs developing on the basal plate (root base) of the bulb while others may even have a little top shoot. Some bulbs are prettier than others, but you can rest assured that all of the flowers will be gorgeous!
Sometimes, you might find a large Allium bulb that appears flat on one side….like a big tear drop with a flat side. It appears like this because the strong woody stem of the Allium came out after dying back in the spring, and the bulb was so huge that it split apart as it continued to grow. Rest assured that this split-apart is a perfectly wonderful bulb, it just looks different from other bulbs. Other times, you might find a beautiful bulb with a hole in the top. Again, this is where the woody stem of the Allium split apart from the bulb after it bloomed and died back in the spring. It’s all good, all natural. Some people plant the bulbs with a hole in the top at an angle to prevent water collection. We don’t know if that really makes any difference since water flows in all directions underground.
However, if you find an Allium bulb with a discolored spot that is soft and you can push your finger into it, please call us. This rarely happens, but if it does, let us know and we will take care of it. That is not a good thing.
Each Allium variety makes its own special top size bulb. Some are as small as 4 centimeters, while others are 20 centimeters/up!
If you find that one bag of Allium bulbs contains larger and smaller bulbs, it is a glass half full or half empty issue. Each of the bulbs is, at a minimum, the top size specified for that variety. They are sized on conveyor belts in the Netherlands that have holes the centimeter size just below the top size measurement. Smaller bulbs fall through these holes and are not included in our stock. All of the larger bulbs are included in our stock, and, as a result, there can be size variation. But it is definitely a glass half full! (If any variety in any season produces a smaller top size bulb than expected, we note it on our website. If a price change occurs as a result, we post the new price and make an adjustment on every order.)
Bulb Storage Before Planting
After you’ve received your order and inspected it, keep the exterior carton and the inner boxes open to give the bulbs some air. All bulbs love good air circulation. Store them in a cool, dry place with low humidity, away from heat, frost and strong sunlight at about 50°F to 70°F. Never put flower bulbs in the freezer! Poor storage conditions could cause bulbs to dry out, or to become moldy.
Select and Prepare the Planting Site
All Allium require rich, well-draining and neutral pH soil. The best soil is a sandy loam. For clay soil, break up the clay about a foot deeper than the planting depth of your bulbs and amend the bed with sand, peat moss and/or well-aged, neutral pH compost. For excessively sandy soil, amend the bed with peat moss, aged leaf compost and/or well-aged, neutral pH compost.
Please do not ever add horse manure, chicken droppings, mushroom compost, other hot manure or immature compost to your flower bulb beds. If you would like to add compost you’ve made yourself, please make sure that it is completely decomposed, healthy and neutral pH. Partially decomposed compost can spread fungal disease, such as botrytis blight, and nasty pests. What is good for vegetables is not necessarily good for flower bulbs.
Allium require full sunlight (a minimum of six hours per day) although there are several varieties that can also thrive in partial or filtered sunlight: A. cowanii, oreophilum and siculum bulgaricum.
Most Allium can handle, and even benefit from, a summer dry period. One exception is A. unifolium, which can handle soil with a bit more moisture than other varieties.
Easy to Plant
Allium bulbs are so easy to plant and are really low maintenance. We’ll ship you the bulbs in time for planting in your garden in the fall, once the ground has chilled down to about 55°F, after about two weeks of sweater weather when night time temperatures have hovered in the 40s. This is the best time to plant Allium bulbs. Flower bulbs do everything in response to temperature and sunlight. If bulbs are planted too early, before the ground has chilled down to around 55°F, they may grow unnecessary top growth, which could diminish their vitality in spring. If they are planted too late, all-important root system growth could be hampered. Immature, underdeveloped root systems could result in more foliage than flowers. Not good.
Plant the big bulbs 6″ to 8″ deep and 8″ to 10″ apart and plant the smaller bulbs 4″ deep and 3″ to 4″ apart. Please do not put anything in the bottom of hole that you’ve dug for the bulbs. Even if you think it is good for the bulb, it could cause root burn. Nestle the bulb into its hole, fill in the hole with soil to the level of the bed, and tamp down the soil lightly, making sure that individual holes are no longer apparent and that the garden bed surface is level. This will help to prevent water from filling up any of the individual planting holes. All flower bulbs hate to get wet feet.
Never put anything, including fertilizer, in the bottom of each bulb planting hole. To do so is to run the risk of root burn. Plant the bulbs to the proper depth and spacing, tamp down the soil and broadcast a 5-10-5 or 4-10-6 granular organic fertilizer over the surface of the bed as if you were feeding the birds.
While all flower bulbs are nature’s perfect little packages and will bloom beautifully the first year, we recommend broadcasting fertilizer three times a year for all perennial and naturalizing flower bulbs. First at the time of fall planting to help grow the roots, second when the sprouts emerge in the spring to help nourish the foliage and flower, and finally, when the flowers start to die back to help feed the bulb itself. Bone meal is incomplete nutritionally and can attract animals to some varieties of bulbs (like Crocus or Tulips).
Do Not Plant Allium in Exterior Containers /Raised Beds
Flower bulbs should never be planted in outdoor containers, window boxes or raised beds where bulbs experience temperature spiking and repeated cycles of freezing and thawing. This results in root growth failure, root system destruction, frozen bulbs and/or bulb rot from poor water drainage. Flower bulbs must have a consistent cold winter temperature with good water drainage in order to produce a mature root system that will permit foliage growth and flower production in the spring.
Bloom Times, Size and Color
The bloom time listed for each variety is for horticultural zone 5 in normal spring conditions. The warmer the horticultural zone, the earlier flower bulbs will bloom. The colder the horticultural zone, the later flower bulbs will bloom in the spring.
Flower bulbs do everything in response to temperature, sunlight and site conditions. Bloom times, heights and colors are approximations affected by temperature and site conditions regardless of the calendar date. If it is a warm spring, bulbs will bloom earlier. If it is a cold spring, bulbs will bloom later. If it is a long cool spring, followed by rapid warming, you may find odd bedfellows: earlier blooming Galanthus flowering right along side later blooming Crocus, Species Tulips and Narcissi. Each spring can offer a different sort of garden surprise party.
In the event of a mild winter or a warmer-than-usual spring, flower bulbs that have emergent stalks with set buds may bloom early, small and short, although they will likely grow taller and larger as temperatures moderate. Temperature spikes can also affect mature root development, the actual form of the flower or the process of flower color maturation.
Allium have all different sorts of stems and stalks, buds and flowers. Allium schubertii initiates spring growth with a low rosette of foliage from which a stout stem emerges sporting a thick paint brush of a bold bud. Allium sphaerocephalon emerges with thin wiry stems that could be mistaken for weeds. Allium Forelock develops thin stems sparsely covered with leaf-like foliage: the sheath-covered buds point in all directions atop the wiry stems that dance among themselves in wild curly-cues. Allium Ambassador, Gladiator, Globemaster and Pinball Wizard have thick stalks that boldly come forth with incredibly buxom buds whose sheaths finally burst open to reveal tightly compacted florets waiting to explode. Allium siculum bulgaricum stealthily enters the garden with slender green stalks from which paper-sheathed hot Chile pepper look-alikes, kind of like vegetative spears, appear.
Although it is not pretty, it’s completely natural that the low-growing foliage of some Allium, particularly the large globe-shaped varieties, starts to yellow and brown out before and/or during the bloom period. We’ve known some fastidious gardeners who have trimmed off the dead Allium foliage tips prior to Garden Conservancy Open Days, but we recommend letting it do its thing. Just don’t focus on it. It’s a small price to pay for such magnificence.
Once Allium bloom and start to die back, make sure to keep the foliage going until it dies back naturally. A maximum period of photosynthesis allows the bulbs to regenerate for the future. Once the foliage is completely yellowed or browned out, remove it from the garden.
Don’t forget that Allium are amazingly wonderful cut flowers! One year, Mother Nature condensed our spring bloom period and the big globe-shaped Allium were blooming at the same time as the Peonies. Allium Globemaster and Peony Eden’s Perfume were stunning in a tall vase for Father’s Day.
The larger globe-shaped Allium are also terrific dried flowers. It’s fun to experiment with them: one year, my sister spray painted dried Allium Globemaster orbs gold. Fun.
While most Allium are not recommended for forcing over the winter, there are several varieties that are known to be good forcers: A. cowanii, karativiense, karataviense Ivory Queen and unifolium.
In general, to force any of these select varieties of Allium, one would pot the bulbs in mid-October and prechill them at a consistent, dark 38°F to 45°F with moderate watering for eight to ten weeks. At the end of the precooling period, bring the pots out of refrigeration into progressively stronger sunlight with moderate watering. They usually bloom around four weeks later. Once Allium bulbs are forced, their vitality is spent and the bulbs may be discarded.
If Allium are yielding more foliage than flowers, it normally indicates a root system issue. A mature planting may need to be dug up in the fall, and transplanted to the original depth and spacing after carefully separating the bulbs that may have been strangling themselves. Sometimes, the larger Allium bulbs grow to the point that they split apart at the area where the woody stem has separated itself from the bulb. It can take years for each split-apart bulb to grow to the size whereby it would fully flower again. Please do keep the foliage growing and dying back naturally during this time.
It may not happen often, but we’ve found that on occasion, Allium aflatunense Purple Sensation has reseeded itself and popped up happily in other parts of the garden.
We are very sorry, but due to state agricultural restrictions, we are not permitted to ship Allium bulbs to Idaho, or to the following five counties in the State of Washington: Adams, Benton, Franklin, Grant and Klickitat.
Most of us don’t think of onions as beautiful plants, but onions have some very close cousins who definitely deserve a place in your flower garden. As with onions and garlic, the ornamental alliums have round flower heads composed of dozens of star-shaped flowers. However, these plants are not edible, although their leaves do have a slight onion-like scent when crushed.
The ornamental alliums won’t spice up your cooking, but their cheerful spherical flowers will enliven your garden. These are extremely tough plants that are both drought resistant and cold tolerant. They’re not even bothered by deer or rodents. And there are plenty to choose for any garden.
The majority of alliums are bulb-forming; however, there is a handful that grows from rhizomes, the way common chives (Allium schoenoprasum) do. These may never form any kind of bulb.
- Leaves: Allium leaves tend to be long and strappy. Some—like the cork-screw allium—remain attractive all season, with a blue-green color that complements the flowers. Most early blooming alliums have foliage that tends to die-back early, as the plants go dormant for the summer.
- Flowers: The flowers form in clusters and are best known in the round pom-pom form, but they can be star-shaped, cup-shaped, semi-circular, or pendulous.
Each species or cultivar has its own common name, but they are all known as “Ornamental Onions”.
Hardiness depends on the variety being grown and the growing conditions, but most alliums will do well in USDA Hardiness Zones four to ten.
There’s a good amount of variety in Allium plants. Drumstick alliums only grow about one foot tall with one-inch flower heads, while giant ‘Globemaster’ can top four feet in height and sport huge globes of eight-to-ten-inch flower heads. You will need to read the descriptions closely.
For the best flowering and healthiest plants, place your alliums in a site that gets a full day of sun. They will grow in partial shade, but since so many of them have short seasons, give them as much sun as you can.
Bloom Period or Days to Harvest
Most alliums bloom in spring or early summer after the earliest spring bulbs have faded. However, there are a few varieties that bloom later in the season, even well into fall.
Alliums prefer a soil pH that is slightly acidic, at around 5.5 to 6.5. However, how well the soil drains is far more important than soil pH. Do not let the bulbs sit in damp soil, especially during their dormant season. If they remain wet for too long, they will rot. Adding a good amount of organic matter to the soil before planting will improve draining while allowing enough water to reach the bulbs.
The bulb forming alliums will need to be planted in the fall. The planting depth should be two to three times the diameter of the bulbs. (So if you have a two-inch bulb, you would plant it four to six inches deep.) Water them well after planting. Then cross your fingers and wait for spring.
The rhizome forming alliums can be planted anytime. You may not find the fall-blooming varieties in the garden center until late summer. These should be planted at the same depth they were in their containers.
You can start alliums from seed, but many of the more popular varieties are hybrids and won’t grow true. If you want to try your hand at growing from seed, harvest and sow them as soon as they are dried on the plant.
Alliums are very low maintenance. They will need regular water, especially while in flower, if rainfall is minimal.
If you regularly amend your soil, you may not need to feed them at all. However, if your soil is less than ideal, a little-balanced fertilizer as they start to set flowers will help them replenish all the energy they use blooming.
Alliums do not repeat bloom. You can the flower stalks down after flowering in order to send the plant’s focus back into storing energy in the bulb. However, the dried flower heads are as attractive as the live flowers and many gardeners like to keep them standing. Some even spray paint them and surprise garden visitors.
Bulb-forming alliums are very slow to multiply; however, they will eventually start forming small offsets on the original bulbs or perhaps even on the flower head. Once the plants have finished flowering, you can lift the bulbs and remove the offsets. These can be replanted immediately, but it may take a couple of years before they flower.
Rhizome forming alliums can be lifted and divided any time the clump starts looking crowded. Don’t wait until the center of the plant dies out, before dividing.
Pests and Problems
Ornamental onions, like their culinary cousins, don’t attract too many pests. Deer and rodents avoid them.
They can get a few fungal diseases, like downy mildew and rots, but these are not as much of a problem in a flower border as they would be in a vegetable garden.
As far as insect pests, watch out for snails and slugs, as well as the allium leaf miner. However, since the foliage does not last very long, cosmetic damage to the leaves is not something to worry about.
The plump, round shape of the flowers looks charming poking through other plants, whether low growing mats such as hardy geraniums or shrubby roses. The purple color is a great asset that complements most other late spring flowers, from peonies to iris to catmint. The shape also works well with other medium height plants, like foxglove, that provides a form contrast or Monarda, which provides a form echo.
The big drawback to early-blooming alliums is how their leaves can start to go downhill, even before the plants have flowered. If at all possible, try to hide the foliage behind a denser plant. Daylilies work well for this.
Big Ball Alliums
This group, the big ball onions with great spherical heads of bloom, is probably the best known of all the “ornamental onions”. The group is better known as Allium section Melanocrommyum, with Allium giganteum probably the most famous of the lot. Available in the autumn where Dutch bulbs are sold, these spring to early summer blooming onions are easy to grow when given good drainage or light loamy soil in full sun, making spectacular accents in the garden. They dry up and retreat into dormancy immediately after flowering.
Allium ‘Gladiator’ is one of the many giant ball-shaped onions in varying shades of purple. This one is a cross between A. hollandicum (syn. A. aflatunense of Hort.) x macleanii (probably). It has robust growth green leafage, tall stems of about 4′ (120 cm), and lilac-purple flowers. Photo by Mark McDonough.
Allium ‘Globemaster’ is a fantastic cross (Allium macleanii x cristophii) made by Jan Bijl, requiring nearly 20 years to bring it into commercially scaled production. It has dense globes of purple starry flowers that have that same metallic sheen evidenced by Allium cristophii (often misspelled “christophii”). The floral globes start out 4-5″ across, but since the new buds pop out just beyond the spent blooms, the great spheres of bloom grow in size over several weeks. Under good conditions, the bloom heads can exceed 11″ (28 cm) across! One of the best features of the “big ball” type of alliums are the fantastic seed heads. In the second photo taken 3/6/03 there are two dried ‘Globemaster’ seed heads. The dried seed structures are about 8 years old now, but still hold their decorative appeal. Photographed up against a brick wall, and knowing that a brick is 8″ (20 cm) wide, you’ll get a good idea just how huge the bloom heads can get. Photos by Mark McDonough.
Allium ‘Globus’ is reportedly a hybrid between A. karataviense and possibly A. cristophii. Much shorter stature to about 18″ (45 cm) or a little taller, and undiminished balls of purple. Photo by Mark McDonough.
Allium ‘Lucy Ball’ is another cross from the same parentage as ‘Gladiator’, namely between A. hollandicum (syn. A. aflatunense of Hort.) x macleanii (probably). The cultivar seems prone to rot in my garden, and I haven’t bothered replacing it recently. The first photo shows the tight buds, and the second photo shows an inflorescence at full anthesis. Photos by Mark McDonough.
Allium ‘Mount Everest’ is a hybrid of A. stipitatum and A. hollandicum produced by Langendijk Brothers in Holland. The stems are over three feet tall and flowers about 5 inches across; it blooms around the end of May, slightly later than the typical purple big ball alliums. It is similar to Allium ‘Mont Blanc’. Photographs by David Pilling.
Allium backhousianum Regel is a tall (over 100 cm) onion with greenish white flowers. It grows best in a sandy well drained medium in a sunny position. Photo by Wietse Mellema.
Allium cristophii (often misspelled as christophii) is a species with blue-purple flowers. It is native to central Turkey (Kayseri), northern Iran, and Turkmenistan. It widely cultivated. In cultivation, I put the plants into a dry summer dormancy after flowers/seeds have developed. When winter comes around, even if water is available, the bulbs will only make roots and will not emerge until spring. Flower photos by Nhu Nguyen. Photo 1 shows details of the flowers. Photos 2-3 show the inflorescence(s) grown in the ground in front of a dazzling display of the iceplant Drosanthemum bicolor. Bulb photo by David Pilling.
Allium jesdianum ssp. angustitepalum was previously sold as A. rosenbachianum (a very different species). It seems that the nomenclature is sorted out. I like this species as it has beautiful two-toned flowers (rose-purple and prominent white stamens), held in graceful hemispheres, on stems only about 24-30″ (60-75 cm). There are several named cultivars, but I like this subspecies the best. Photo by Mark McDonough.
Allium karataviense Regel is a native of Central Asia where it grows in loose limestone scree and blooms in April and May. It is a popular rock garden plant with flowers that are dried for flower arrangements. It also had beautiful broad foliage. In the first two photographs below taken by Mark McDonough we see regular A. karataviense on the left (purplish tinged foliage) and A. karataviense ‘Ivory Queen’ on the right (no purple tinge). The next two show 3 different forms of wild collected Allium karataviense, showing considerable diversity in foliar and flower form. The one in the center, with red flowers, is from the same locale where ‘Red Globe’ was first collected. All three collections are from Central Asia. The final photo by Oron Peri is of A. karataviense in its habitat.
Photos below by Wietse Mellema of a huge bulb and a plant with bulbils, respectively. It is not advisable to propagate Alliums by bulbils, it will likely result in plants that create more bulbils in place of flowers.
Allium karataviense ‘Ivory Queen’ is a fantastic clean white form of this popular species. It flowers the same time as the regular pinkish form, seen on the left. Photos by Mark McDonough.
Allium karataviense ‘Red Globe’ – This is a recently available form of A. karataviense ssp. henrikii Rukšans that’s very different, flowering much earlier, with much larger and longer gray foliage, and huge globes of dark red-violet flowers. The first photo shows 3 bulbs in full bloom. The second shot shows the inflorescence swelling with red-purple seed pods and the much smaller flower globe of typical A. karataviense in the background. It’s hard to believe that this hasn’t been identified as a new species of subspecies of A. karataviense. Evidently, A. karataviense in the wild is extremely variable. Photos 1-2 by Mark McDonough. Third photo by Wietse Mellema.
Allium schubertii is a fantastic, whimsical giant onion, with flower pedicels of various length, creating a big spidery ball of blooms. Not reliably hardy in cold climates. – The first photo was taken by Lauw de Jager. The second from Kelly Irvin is an example where they are planted too close together. This picture might help with imagining the actual size of the inflorescence. The young model accompanying the onions goes by the name Gabriel. The third was taken in its habitat in the Golan Heights- Syria by Oron Peri. Photo 4 of commercially supplied bulbs on a 10 mm grid and photo 5 of shoots in January by David Pilling
Allium index -All alliums – Allium flavum Relatives – American alliums A-F – American alliums G-Z – Blue alliums – Chives – Domed alliums – Drumstick alliums – Rhizomatous alliums
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How to plant and grow allium bulbs
Alliums are incredibly long-lived and flower for ages. The ones shown here in my garden at Perch Hill have been coming back year after year for the last twelve years. I love them for adding late spring and summer pizzazz, bringing strong colour and shape to the border. Plus they are excellent for cutting in flower or as seedpods, which I use for Christmas decorations.
Soil and Site
Full sun in well-drained soil (add grit on heavy soils). Nectaroscordum will take some shade and self sows so take care where you plant it.
The small and middle sized alliums (A. cowanii, ‘Hair’, ‘Purple Sensation’, sphaerocephalon, atropurpureum and Nectaroscordum) can be planted en masse. Depending on the size of the bulb, plant 10-15cm deep and 10-15cm apart. I tend to plant in good drifts, rather than in twos and threes to avoid a dotty look.
The larger varieties (A. ‘Globemaster’, cristophii, ‘Purple Rain’ and schubertii) can be planted in groups or individually at a depth of 15cm, but need more space for their much larger heads: A. cristophii and ‘Purple Rain’ need to be at least 30cm apart, and ‘Globemaster’ and schubertii need spacing at 30-45cm.
In the garden
To make them more perennial, bulbs should be planted deeply, at least twice the depth of the bulb. Dig a hole or trench, and on heavy soil spread a 5cm layer of grit (or spent compost) all over the bottom. Push your bulbs into the bottom of the trench/hole, leaving a gap of at least 3 times the bulb width between each bulb (see above) and then cover them up – if on heavy soil, mix in about one-third grit to two-thirds soil. After planting, firm the ground with your hand (using your feet can trample the crowns) to get rid of air pockets – watering will help this too.
On poor soil, it’s worth giving almost all spring-flowering bulbs potash feed in the early spring. This helps with root and bulb formation and will encourage them to stick around and flower on and on for years.
Bulbs should be planted in pots at the same depth as bulbs grown in the ground. This may not always be possible with the largest bulbs as it’s important that a large bulb has at least 4cm of compost beneath it. Use good quality multi-purpose compost and top-dress the pot with a generous layer of grit.
In large pots containing multiple bulbs, plant them one bulb width apart in lasagne layers, one layer of one variety, the next layer the next and so on, with the smallest bulbs forming the layer nearest the top. Cover with compost and firm well.
All bulbs do best if you minimize the number of leaves you cut when you pick the flowers. When you cut, make sure you leave a short section of the leafy part of the stem to give the bulb a chance to make enough food to survive through the dormant period.
It is also important to leave the browning foliage on your bulbs until every leaf has died right down. Don’t be tempted to clear them up until every leaf is completely brown. This is the time when bulbs photosynthesise and create food, stored in the bulb to help next year’s flower. If you remove the leaves half way through this process, you’re less likely to have a flower the following year.
I don’t lift any of my bulbs in the garden; planted deeply and mulched with a generous blanket of mushroom compost I leave them in the ground to over-winter. If you’ve grown them in containers and you notice any small ‘bulblets’ these can be kept and planted into a separate pot, and will reach flowering size in a couple of years time.
Add a drop of bleach to the water to minimise the oniony smell or change the water regularly. They will look good for up to 2 weeks without rearranging.
You may also like:
- Planting artichokes with alliums
- What to do with your allium seedheads
- Blog: A shout out for alliums
The Sunday Gardener’s Blog
It’s not to late to plant Allium bulbs for a great spring display. In the right place, Alliums are low maintenance and will return reliably every year and are surely one of the most stylish plants for a border, illustrated by the images.
Alliums like a sunny spot with well drained soil, which means they are unhappy on wet boggy soil especially over winter, which can cause the bulbs to rot. If you do not have ideal growing conditions Alliums can be raised in containers for a patio display, or place the containers in the borders.
Alliums are wide ranging in size, from the quite small suitable for the front of the border such as Chives which the bees love (2nd image) and A. Moly, which is a bright yellow variety, both of which grow to around 30cms. Chives make a great edging plant, fodder for us and the bees.
Amongst the taller varieties Allium Cristophii (illustrated 3rd image), spectacular with it’s spikey flower heads and A. Globemaster one of the taller varieties over 1m.
Alliums need to be planted in early Autumn so from September up to mid/3rd week October is best. Buying and planting as bulbs is much cheaper than buying as plants next spring. Like all bulbs the rule of thumb is to plant 4x the depth of the bulb, and if you are container planting a deeper pot is best.
There are also unusual varieties such as Nectaroscordum siculum, (6th image) technically not an Allium, but often sold as one.
Alliums look great planted on mass, as in the images 4 & 5, which is in an RHS garden, but most of us don’t have that much space. In smaller gardens Alliums can be used to great effect as a theme, planted in groups,reoccurring maybe 3/4 times, will give a border real style.
Taller varieties may need staking, especially in exposed areas. Allium are easy to grow and make a fabulous show. Good value for money as they will return and flower year after year with very little attention.
The leaves on Allium are not attractive, especially after flowering and traditionally Allium are planting with companions to cover up the leaves such as Achillea Mollis or Euphorbia.
More about growing Alliums and planting combinations.
Controlling Allium Plants – How To Manage Flowering Onions
Allium, known for its pungent aroma, includes more than 500 species, including the familiar onion, garlic, chives and a variety of beautiful flowering plants. Pollinators love the hardy, long-lasting plants, but deer and other critters usually leave them alone. If ornamental alliums are so practical and attractive, how could there be any problems with ornamental alliums in the garden? Read on to learn more.
Are Alliums Invasive?
Not all allium varieties are well-behaved. Some become weeds that are nearly impossible to get rid of, especially in mild climates. The bad news is that dormant bulbs can remain in the soil for up to six years.
The biggest offenders are wild allium (Allium ursinum), wild garlic (Allium vineale), and three-cornered leek (Allium triquetrum). All three spread like wildfire, quickly choking out gentler plants that you try to establish in your garden.
There’s really no easy answer when it comes to controlling allium plants. Be patient and persistent, as it will probably require several go-rounds. Oregon State University says to expect
the process to take a minimum of three or four years, and maybe even more.
Controlling Allium Plants in the Garden
If you need more information on how to manage flowering onions, here are a few tips:
Pulling: Pulling may help, but only if you can manage to get all the bulbs. The problem with pulling is that tiny bulbs often break off when you pull the clump, and it’s very difficult to get them all, especially if your soil is hard and compacted.
Try pulling after a rainfall or water the area deeply a day or two ahead of time, but be aware that pulling may not be the final solution.
Digging: It isn’t much fun, but digging the old-fashioned way is probably your best bet when it comes to getting rid of invasive ornamental alliums in the garden. Dig a deep, wide area around the clump to get the tiny bulbs. Repeat the process every two weeks throughout the season.
Don’t shake the dirt off the clump; just place the entire plant into a box or bag so stray bulbs don’t escape. Discard the clumps, soil and all. By all means, don’t put the clump in your compost heap.
Mowing: Mowing doesn’t get rid of the underground bulbs, but cutting off the tops prevents blooms from developing seeds that generate even more plants.
Herbicides: Chemicals are generally ineffective because the substance doesn’t stick to the tall, slender, somewhat waxy leaves and does little to combat the underground bulbs.
However, if you want to give it a try, use a product containing 2-4,d, glysophate or dicamba before the plants reach 8 inches (20 cm.) tall. Mow immediately before treating the allium because newly mowed leaves have rough edges that improve absorption.
Controlling Allium in Lawns
If allium plants are popping up in your lawn, be sure to water and fertilize regularly. A healthy stand of grass is more likely to choke out the invaders.