Keep compost moist
Harden off any soft growth occurring in early spring
Make sure rootball is thoroughly moist before planting.
Keep approximately 12”(30cm) away from walls and fences; 2-3ft (60 – 90cm) from shrubs or trees.
Dig hole large enough for rootball and manure, and deep enough to cover stem bases.
Add well rotted manure or garden compost plus a good handfull of bonemeal in hole. Mix well with soil at base of hole. If dry, fill hole with water and allow to drain. MIX ALL RAW INGREDIENTS WITH SOIL.
Loosen roots if necessary and plant in hole so lowest leaf joint(s) will be buried.
Backfill hole and gently firm taking care not to damage stem bases. Carefully remove ties and cane and tie stems to support.
Water well, then regularly, as necessary throughout the growing season, particularly during periods of dry weather.
Clematis benefit from a mulch of well rotted manure, bark chippings, stones or natural shading eg. a small shrub; particularly if grown in a sunny, hot position.
It is recommended that all clematis be hard pruned in the first year of planting. This benefits the initial growth and development of your new clematis, ie:-
Group I (Tidying)
Hard prune immediately after first years flowers have finished.
Group II (Light pruning)
Hard prune end February/Early March in first year of planting.
Group III (Hard pruning)
Hard prune end February/Early March.
Hard pruning involves cutting all stems to just above a good pair of buds (at base of leaf joints) approx. 6-9”(15-23cm) from ground. Clematis should be pruned, according to group, after this first hard prune.
Group I – Tidy After Flowering eg. C .armandii, atragenes, cirrhosa, montanas, etc.
Prune any unwanted/untidy growth immediately after flowering. This is to keep vigorous growth in check and within the confines of the space provided.
Harder pruning will help prevent stems becoming too woody and growth getting out of control. However, flowering may be delayed for one season.
Group II – Light Prune eg. Early Summer Large Flowering Clematis
Remove the top third to half of the plant by pruning all stems just above a good pair of healthy buds, during February/March. Any weak, dead or damaged stems can also be removed. If possible prune one or two stems near to ground level to encourage new growth low down. For older plants and rejuvenation, prune out top half of stems during late autumn, then hard prune all stems as per Group III.
Group III – Hard Prune eg. Viticella, texensis, herbaceous cultivars, species, etc.
During February/March, prune all stems just above a pair of healthy buds about 6”- 8” (13 – 45cms) above the ground. Plants could be “tidied” by removing the upper half or two thirds of stems during late autumn. Herbaceous “heraclefolias” should be hard pruned around April time. Some herbaceous types can have completely dead stems cut to ground level during late winter – take care not to damage any emerging new growth.
All these clematis would do better grown in pots. Please refer to section “Clematis in Containers” for these cultivars. Grow outside from late spring to early autumn, then under cover in an unheated glasshouse or conservatory. Remember to harden off before placing outside in the new year.
i) Atragene, Heracleifolia, Recta, Tangutica groups and flammula, rehderiana and other species
These prefer poor, well drained, open soils. Atrogenes do not require deep planting. Prune herbaceous heracleifolias hard in April. Old growth gives winter protection.
ii) Evergreen clematis ie. Armandii, cirrhosa, kweichowensis, napaulensis, Winter Beauty, etc
Grow in sheltered places preferably away from cold cold winds in well drained soil. Walls and fences offer good conditions. Evergreen clematis may look “tired” during summer due to their resting period. Don’t forget to feed and water.
iii) Evergreen New Zealand group
Unless growing in mild, sheltered climates, these clematis are best grown in pots in a cold greenhouse or conservatory. Make sure compost is particularly free draining.
iv) Florida group
Grow against a south or south-west facing wall or fence in very free draining soil. Frost protection is very beneficial. Remove this in February or March to prune. Feed with bonemeal and replace protection until weather warms up.
Containers should be as large as possible, at least 18” (45cm) diameter and depth. Terracotta ones are best but try to avoid plastic. Ensure good drainage holes and use plenty of crocks, large stones or gravel at the bottom. Raise container off the ground using pot feet or blocks.
Compost should be soil based; ideally 75% volume John Innes No.3 plus 25% volume multi-purpose. Evenly mix 2 to 3 good handfuls of blood, fish and bonemeal to the compost and plant clematis at the correct depth. Water well and regularly throughout growing season. Do Not keep compost too wet over winter and always check drainage. Feed with Tomorite regularly from late spring to autumn.
When pruning remove 2 or 3 inches of compost from top and top-dress with fresh compost plus a handful of bonemeal, then water in. Every four or five years remove rootball completely during late winter. Cut off 3” (7cm) of rootball all around the outside. Cut one third of rootball from bottom then repot using fresh compost mix.
Cultivars that flower during two main periods of the year should be treated as Group II cultivars. If they are hard pruned flowering will be mainly late as one flush. If hard pruning stops flowering, light prune the following year.
Dead Heading: Particularly useful for early, large flowering cultivars to promote further flowers. Can be used on other cultivars to “tidy” the plant. Do NOT deadhead those cultivars that produce decorative seed heads if this is what you want.
Feeding: Work in a good handful of bonemeal around the root zone after main pruning and water in. In April, work in a good handful of sulphate of potash and water in; or alternatively apply Tomorite once per fortnight from May to September. Mulching with well rotted farmyard manure or garden compost in autumn will help conserve moisture. Keep away from stem bases.
Pest Control: The main pest is aphids, and at times red spider mites. Control can be had by using an insecticide spray – try to use different active ingredients to help prevent build-up of resistance. Slug and snail control is very important as they can produce effects similar to clematis wilt. Check for stripping of bark on stem bases. New growth just below the soil surface can be particularly vulnerable. Use your preferred control method ie. Slug pellets, liquid or organic products. More recently, all these pests can be controlled biologically with nematodes or other natural predators.
Diseases: A powdery white covering to the leaves mid-season could indicate powdery mildew infection. Control by fungicides of your choice. This is particularly important for those cultivars prone to clematis wilt.
Clematis Wilt: This is evident by a sudden “wilt” of young growth downwards. If no other cause is seen, cut down affected stems to first leaf joints above ground. Drench soil around stems with fungicide twice, 1-2 weeks apart. Not all cultivars are prone to wilt – especially species or viticella groups.