Planting Clematis – A Step-by-Step Guide
How to Plant Clematis
These instructions apply to all the clematis in our range. Planting clematis in the average garden is pretty straightforward and they will grow practically anywhere as long as you remember five things – Preparation, depth, water, temperature and the first prune.
- Take out a good sized hole – this should be at least twice the width of the pot in which your clematis was grown and half as deep again assuming a 2-3 litre pot size.
- Remove all roots, weeds, stones and other rubbish and improve the soil with the addition of well-rotted manure or compost.
- Use either root grow or bonemeal when planting, but not both.
- Pinch off any leaves that will be buried when planting is finished.
- Water the plant well and remove from its pot.
- Without breaking any, carefully tease out a few of its roots to help them out of the rootball and into the surrounding soil.
Plant clematis deep
All clematis prefer to be planted so the crown of the plant – this is where its stem(s) emerge from the compost in which it was grown – is at least 3-4 inches (6 cm) below soil level. I plant well-grown clematis with a strong stem deeper still at about 6″ and it has always served me well.
Planting deep helps promote growth from below soil level which is good because it lessens the chance of your clematis becoming diseased and increases the speed at which they cover whatever you have planted them against or under. Our plants are well enough developed to be planted like this immediately.
If you buy very small clematis plants in liners – 9cm pots then although you place the plant deep in the hole, you do not return the soil around the stem until it has become woody which is usually the winter following planting.
Until a clematis has established and is growing away well, it will need plenty of water. They are thirsty plants and (if you followed the instructions above) their roots were planted deep, so plenty really does mean that. Having said which, they also demand good drainage. This is one of the reasons they do so well on chalky and sandstone soils – the soil retains moisture, but never puddles.
If you do not have good drainage, then “Preparation” includes improving it to the point where you do (have good drainage).
If you are on heavy clay, plant clematis on a slope and dig a relief trench away from the planting hole, down the slope to help water movement. If none of that is possible, make a good sized mound – say 20 cms (12″) tall and twice as wide and plant in that.
Some like it hot, and some…
Most clematis love the sun, but only on their tops. There are a few that fade in direct sunlight but in the main a very light, airy place is good. For the top half, that is.
The roots, on the other hand, hate warm (and probably dry) soil. They must be kept shaded and cool. The traditional method for achieving this is by covering the root area with loose paving or stone slabs. Bricks also work well.
Less commonly seen, but I think easier on the eye and just as effective is to use ground cover or shallow-rooted shrubs. Plant something that will not compete for nourishment with the deep roots of the clematis. Hostas are excellent for this and so are the larger sedum, true geraniums and so on.
Once you get started, planting shade for clematis roots can become obsessive. This method has the beneficial side effect of covering what the late Christopher Lloyd described as a clematis bad legs.
It is tempting to plant your lovely, leggy (see above) clematis and let it get on with it. In fact all newly planted clematis benefit from being cut back to just above a leaf node no more than 12″ off the ground. 6″ is even better.
This first prune encourages the plant to sprout from the base and gives you a much bushier healthier plant.
If you really must, let it flower, but sometime between planting and the following November, cut all clematis back hard.
Peter Cundall: Plant clematis in early winter
THE best time to plant clematis is probably during autumn to early winter, although they can be put in at any time of year.
Like most climbing plants, they must grow into the sun in order to flower.
Most are perfectly suited to climbing deciduous fruit or ornamental trees.
They even wind their way up other climbers, including roses.
Clematis detest heavy, badly drained, acidic soil or where strong, persistent winds prevail.
A good, medium-rich loamy soil is ideal.
If planting close to a tree, find a gap between big tree roots about half a metre from the trunk.
Excavate the soil and plant into this gap.
Clematis plants develop powerful roots that easily compete with all but the most aggressive tree roots.
Always try to dig a hole at least three times wider than the existing clematis root-ball.
If conditions are dry, fill the hole with water several times and allow to soak away.
Most clematis varieties develop lots of tough roots while in pots awaiting sale.
Some may have started to spiral around the base of the pot.
Soak the root ball so softened roots near the base can be partly teased out.
Clematis are best planted a little deeper than the surrounding soil.
This encourages more stems to form, ensuring sturdier plants.
The best fertiliser is well-rotted compost, mixed into the base and sides of the hole.
Backfill with top- quality potting soil mixed with decomposed organic matter and water thoroughly.
If growing near a tree, use a thin stake to guide a new plant to its host.
Clematis can also be grown in tubs with a minimum width of at least half a metre and filled with good quality potting soil.
Well-shaded, cool roots are vitally important with clematis so, if necessary, spread a layer of flat stones around new plants.
The initial pruning is fairly hard and is best carried out in late winter.
Make the cut so just two pairs of fat buds remain, just above the ground.
Clematis plants need constant watering during dry, warm periods.
Those in tubs or troughs must be watered every day during hot weather.
Each August, sprinkle blood and bone fertiliser around plants.
Add sulfate of potash at the rate of a tight fistful per square metre.
Small flowering clematis such as C. montana produce single displays in spring. Colours range from white to various shades of pink and some are scented.
As old plants become tangled, use hedge-shears to cut them back, always after flowering.
Large-flowering clematis bloom in spring and summer and can be pruned to flower again in autumn.
The method is to cut back mature plants hard (about half a metre from the ground) every August.
These shortened plants rapidly sprout new growth within weeks.
By mid-January, all spring and early summer flowers will have finished. The plants can then be lightly pruned again — mainly deadheading — especially to remove immature seed heads.
This, with regular watering, forces plants to try again, often producing a satisfactory autumn display.
Clematis armandii, C. aristata and C. integrifolia need only a light pruning after flowering without cutting into old stems.
Varieties such as C. montana, C. alpina and C. macropetala produce flowers from previous summers’ growth and are mainly deadheading after flowering.
Large-flowering cultivars, including Belle of Woking, Niobe and Ville de Lyon, flower from stems sprouting from the previous season’s wood.
Cut off all seed heads and remove dead and weak stems down to the next pair of healthy buds in late winter and late January.
Varieties that bloom in autumn such as Jackmanii, Viticella and Texensis hybrids are pruned in late winter by cutting off all top growth, always avoiding old wood. Choose a pair of healthy buds and cut just above them.
Clematis are tough plants and even rough pruning gets great results. If unsure, prune all large flowered clematis to about 30cm from the ground every August.
Spring-flowering shrubby forms are best pruned after flowering in late spring.
As for the outstanding Apple Blossom (C. armandii), just leave this one alone apart from removing dead growth.
Clematis – Evergreen Group
As climbers, Clematis are unsurpassed in their long flowering presence, their rich diversity of flower shapes, their wide array of colors and tolerances in terms of exposure and climate. It is no wonder they are so popular! From tree huggers to container varieties, there is a Clematis for every garden and flowers for almost every month of the year!
Members of the Ranunculaceae family, Clematis include more than 300 species, hundreds of hybrids and are divided into 12 main groups, each with consistent flower size, blooming season, pruning and garden use characteristics.
The earliest Clematis to flower, the Evergreen group includes small-flowering clematis which provide gardeners with some of the greatest pleasures in winter. Blooming from midwinter onward, these very early flowering Clematis transform boundary walls and fences into leaving leafy screens and reward us with profuse flowering at a time when the garden has little to offer. Their evergreen foliage remains handsome year-round and provides multiseason interest.
The 2 main species that belong to this group are Clematis cirrhosa and the delightfully fragrant Clematis armandii.
- These evergreen clematis produce an abundance of small, single flowers, mostly in creamy-white or white shades.
- They bloom profusely from mid winter onwards, starting with Clematis cirrhosa (January) and followed by Clematis armandii (March-April). The flowers of Clematis cirrhosa give way to very ornamental, fluffy, silky seedheads, which remain on the plant, adding further interest.
- Quick-growing, these clematis are big plants that can reach up to 20-40 ft. (6-12 m). They need ample support as they become heavy with age.
- These clematis require well-drained soils and are ideally suited to growing in sun or partial shade. Adding coarse grit into a large planting hole is a great way to avoid waterlogging during winter.
- These clematis are quite versatile. They can be trained over trellises, arbors, pergolas, arches or fences. Careful: these clematis are not good companion plants. Their thick foliage cuts off light to any host plant, killing it by starvation. If planted into a large broadleaf evergreen, they might kill it via strangulation.
- Since they bloom on the previous season’s wood, they belong to the pruning group 1. No regular pruning required. Just clean them up after flowering.
Thorny problems: how an I manage a huge clematis?
Give in or give up?
Q: I have a variegated buddliea that has developed several branches with plain green leaves – in total they constitute almost half of the plant. Should I remove them, or give in to them?
Janet Tatum, via email
A: Some plants with distinctively patterned leaves are propagated from virus-affected plants whose leaf markings are deemed attractive (the most notable of these are some of the abutilons). But most variegated plants, (i.e. those which have leaves that are only partly green, like your Buddleja davidii ‘Harlequin’), are simply propagated from freak plants that occur naturally, and the colouration can be quite unstable. For example, some of them, particularly when grown in less than full light, revert fairly readily back to their green-leafed state as an act of self-preservation, since green leaves, which contain more of the necessary chlorophyll, photosynthesise (convert sunlight into growth energy) far more efficiently than those with various forms of white, “gold” or red variegation.
If Buddleja davidii was not such a vigorous grower, I would say that you should give up and either be content with an increasingly green-leafed plant, or get rid of it. Reading between the lines, however, I suspect that the green-leafed branches all stem from one area of the bush – and that they maybe all come from a single branch that you cut back a little last spring and that has since sprouted profusely, as buddleias do. If you cut well down into the bush to the very base of the green-leafed “rogue mother” branch, and keep an eye on it as the whole bush comes into growth next spring and tweak off with finger and thumb any green buds that you notice and you may slow down and keep control of the reversion sufficiently to make the shrub worth keeping.
A year for black spot?
Q: My roses, after flowering magnificently this year, have in the last few weeks developed black spot very badly. Some of the leaves are turning yellow and diseased. I spray regularly with Multirose from the first signs of growth in spring. Friends here are, I gather, having the same problems and I wonder if you can offer advice or suggestions?
Paul Fincham, Suffolk
A: For the rest of the autumn you should aim to clear up all the fallen diseased leaves – easier said than done, I know, but in theory it reduces the amount of fungal spores that will hang around the plants over the winter. Also resolve to prune harder next spring, and cut out in particular any stems that are streaked purple/black, an indication that they are badly infected with black spot that will definitely manifest itself next year. Scrupulous cleaning up of all prunings is important, as is cleaning of pruning tools. Feed and mulch your roses next spring to help them fight off disease.
Readers have reported in the past that spraying Sulphur Rose (01858 410725; greenacresdirect.co.uk) on the dormant plants and the surrounding soil in winter has been beneficial. No sprays will defeat black spot completely, but it is probably worth mentioning that since you have been using the same systemic product year after year it might be time for a change, since tolerances can build up. It does mean peering at small print, of course: the systemic fungicide in Multirose that you have been using is the same as that found in Rose Rescue, for example, and also in Systhane Fungus Fighter, but not Fungus Clear. Some of these “cocktails” also include insecticide you might not actually need.
My hedge is thinning
Q: We have a privet hedge in our garden, at least 50 years old, which is looking rather sparse. Is it coming to the end of its life or is there any way in which I can rejuvenate it?
Heather Catterfeld, Hertfordshire
A: At 50, your privet hedge is a bit long in the tooth. But it would be a shame not to give it a year of TLC, just to see if you can pull it back from the brink.
This is not a good time to be drastic with privet since by now it will have virtually stopped growing for the year. But it might be a good idea to grub it out at the base, remove any dead wood and general detritus and give it a very gentle short back and sides so it goes into the winter looking as pukkah as possible. Early next year, give the cleaned out hedge a couple of fistfuls of a general fertiliser per metre, fork this in gently then mulch the whole root area thickly with well-rotted, nitrogen-rich manure. In mid-spring, as growth starts, cut it back more severely, graduating your cuts so that some stems are cut hard back, others less so, to encourage it to sprout and thicken up. If it doesn’t improve much by next autumn, grub it out – you could replace it with slower growing, but ultimately smarter yew, perhaps.
Pick of the week: early autumn blues
A fashionable and photogenic September garden is inevitably awash with silvery waving grasses and late daisies – rudbeckias, echinaceas, heleniums – so many of them misty amber gold and russet red. But, seeing beyond the almost ubiquitous purple-y Verbena bonariensis, there are some terrific blue autumn perennials too.
An absolute personal favourite is Agastache ‘Blackadder’, a lofty and highly ornamental hyssop, wildly attractive to bees, producing 75cm-tall, completely self-supporting stems topped by numerous smoky-violet-blue spires from July until October. As the individual tiny flowers on each spire fade, the spires themselves turn a dusky purple before they go brown, remaining attractive all winter. New shoots are slow to appear in late spring, so in a tight border you have to ensure that new plants are not overwhelmed by bossier neighbours (another reason to keep the previous year’s stems standing). In a sunny, dryish site it is quite hardy though relatively short-lived.
A very old border chestnut, but highly valued none the less for its hardiness, the profusion and long succession of its particularly beautiful clear lavender blue, yellow-centred flowers, is Aster frikartii ‘Mönch’. Flowering starts earlier (in July), and its growth habit is much less clumpy than other asters, I find. It needs to be well supported.
Lucky hunters may find these looking fantastic at a local nursery or garden centre. Or they can be bought online via the Telegraph Garden shop
Write to Thorny Problems at [email protected] or Gardening, The Daily Telegraph, 111 Buckingham Palace Road, London SW1W 0DT. Helen Yemm can answer questions only through this column
Fred Wein Sr., of Clearview Horticultural, the biggest growers of clematis in North America.
The most sociable of climbers, clematis is deservedly called the Queen of Vines. No garden should be without at least two or three. Some gardeners have planted as many as half a dozen at a time to cover a single trellis or arbor.
Choosing the right clematis is the key to success. The selection can be overwhelming. In commercial cultivation at the moment there are at least 50 blue-flowering clematis, 34 pinks, 30 purples, 16 two-tones, 34 whites, 21 reds and 10 yellows.
Once you’ve chosen the colour you like, the next step is to decide what time of year you want it to flower. You can get clematis that bloom in early spring or summer or fall.
New this spring is ‘Morning Mist’ (above), a new hybrid bred by Fred Wein Sr., of Clearview Horticultural in Aldergrove. This is part of a Vancouver series he is introducing, a few cultivars at a time each year. Next year, he plans to release ‘Danielle’ a beautiful blue, named after his granddaughter and ‘Fragrant White’ that has pure white flowers with the slight scent of vanilla.
FRED’S PICK OF FAVOURITES
Looking for a new clematis for your garden this spring? Here’s a guide to outstanding, garden-worthy cultivars, according to clematis expert Fred Wein.
Dr. Ruppel: A vibrant Argentinian-version of ‘Nelly Moser’ with pink flowers with a carmine bar. Grows 1.8 to 2.4 m (6 to 8 feet).
‘Jackmanii Superba’: More vigorous than the common ‘Jackmanii’ with bigger flowers. Grows 4 to 6 m (12 to 20 feet).
‘Louise Rowe’: This pretty English hybrid has pastel-mauve ruffled flowers in May, followed by single blooms during summer. Grows 1.8 to 2.4 m (6 to 8 feet).
‘Multi-Blue’: This Dutch introduction has oversized stamen that make the lovely purplish-blue flowers more decorative. Grows 2.4 to 3 m (8 to 10 feet).‘
‘Pink Champagne’: This Japanese-bred cultivar has bright pink flowers with a purplish tinge from May to September. Grows 2 to 2.7 m (7 to 9 feet).
‘Rhapsody’: An English cultivar with violet-blue flowers with contrasting yellow-green stamen. Grows to 2.4 m (8 feet).‘
‘Cardinal Wyszynski’: This Polish introduction has deep carmine-red flowers from June to September. Grows 2.4 to 4 m (8 to 12 feet).
HOW TO GROW CLEMATIS
Grow clematis so the roots are in the shade and the foliage and flowers are in full sun. Plant the vines at least 18 inches (45 cm) deep. This includes the crown, which probably means burying a little more of your new plant than seems right. There is an old saying about clematis: the first year they sleep, the second year they creep, the third year they leap. Be patient and you won’t be disappointed.
To flower properly, clematis needs at least 5 hours of full sun. The ideal location is a west-facing trellis that is shaded at its base all afternoon. This allows the vine to get maximum light and warmth at the top while the roots get the cool, moist shade they need. Plant a small shrub in front or use large stones to create shade for roots if there is no other available protection.
HOW TO PRUNE
This is the most commonly asked question about clematis. There is a simple rule: if it blooms before June, don’t prune. But it is a little bit more complicated than that.
There are basically three main categories of clematis, classified simply as types A, B and C. The A-types flower in early spring and should not be pruned until after they bloom.
These include varieties of C. alpina, C. macropetala, the evergreen C. armandii and the vigorous cultivars of C. montana. The B-types flower on stems produced the previous season and again later in the summer on new growth.
Popular B-types include ‘Henryi’, ‘Nelly Moser’, ‘Dr. Ruppel’ and ‘Mrs. N. Thompson.’ These get lightly pruned after flowering.
C-type clematis are by far the most popular, flowering in summer, usually from June on. ‘Jackmanii’ belongs to this group. Other C-group stars include ‘The President’, ‘Polish Spirit’, ‘Ville de Lyon’, ‘Mrs. P. T. James’ and ‘Vyvyan Pennell’. All the C-types can be pruned back close to the ground in early spring and will bounce back with full vigour.
Clematis are their own best friends. You can plant several varieties side by side. The art, however, is to plant varieties that give you a natural sequence of blooms from spring to fall. This is easier said than done. Your best bet is to play with the colours and varieties you like and see what happens.
Clematis is a natural partner for climbing roses, especially to complement an arch or arbour. Purple smoke bush (Cotinus coggygria) is also an excellent companion for red-flowering varieties of clematis such as ‘Mme. Julia Correvon’ or ‘Ville de Lyon’.
Magnolia x soulangiana can provide a frame for early-flowering C. alpina, such as ‘Pamela Jackman’ (deep blue) or ‘Jacqueline du Pre’ (rosy mauve).
There are a few other outstanding clematis that are also worth accommodating.
Early spring bloomers
Clematis armandii (evergreen clematis): This has slender, dark-green, leathery leaves and masses of powerfully scented white flowers in March or April. It has been used successfully to drape fences, cover arbours and gazebos and dress up porches and patios. It is slightly tender in the Lower Mainland; if it isn’t planted in a protected spot a cold winter can kill it. Many gardeners, however, have found the perfect place for this marvellous harbinger of spring. Top cultivars are `Snowdrift’ and `Apple Blossom’.
Clematis montana is a vigorous deciduous species that flowers in mid-spring, usually a little after the evergreen variety. Look for ‘Broughton Star’, ‘Alba’, ‘Elizabeth’, ‘Pink Perfection’ and ‘Rubens’. The montana clematis originates from the Himalayas and has been used to form thick, leafy coverings over arches or arbours. It is even vigorous enough to scramble high into tall trees and can be trained to travel along a fence. This type of clematis flowers on growth produced the previous year.
Summer and fall bloomers
Clematis tangutica (golden clematis): This is an exceptionally vigorous form that produces nodding, yellow, lantern-shaped flowers in July. The flowers magically transform into soft, silvery seed heads in the fall. Top names are ‘Golden Harvest,’ ‘Gravetye’ and ‘My Angel’.
Clematis paniculata (also known as C. terniflora): This is another excellent performer that even stays evergreen in sheltered coastal gardens. It has masses of hawthorn-scented flowers from September to October.
Herbaceous clematis can be grown in the perennial border inside metal spirals, obelisks or wigwam structures. Easy to grow, they have been popular in Europe for years. They produce lush foliage each spring and masses of flowers over the summer months. `Davidiana’ has fragrant, lavender-blue flowers; ‘Durandii’ has indigo-blue flowers; `Coerulea’ has deep blue, nodding blooms; `Pamiat Serdtsa’ has violet-blue flowers. Also popular is C. recta ‘Purpurea’, which not only has pure-white scented flowers, but wonderful deep-purple to bronze foliage. They all grow 6 to 8 feet (1.8 to 2.4 m) high.
Clematis florida `Seiboldii’ is a more unusual vine that bears creamy white blooms with distinctive deep purple centres. It can be grown in a container as it only reaches 8 feet (2.4 m) high and requires minimal pruning. It is more tender than other clematis, but can be overwintered if protected from frost.