How to grow clematis

Inspired by a helpful YouTube guide. This walk-through is based on the popular video "How to Grow Clematis in Containers — tips from world authority on clematis, Raymond Evison". Raymond Evison is one of the world's foremost clematis breeders, based in the Channel Islands, with RHS Chelsea gold medals to his name. Even if you're planting in the ground rather than a pot, his advice on planting depth and feeding applies directly.

1. Choose the right variety for your situation

There are hundreds of clematis varieties, which is either exciting or overwhelming depending on your mood. The key things to match are: mature size, flowering season, and pruning group.

For a small garden or patio pot, look for compact varieties — many modern hybrids stay under two metres. For covering a large fence or pergola, the vigorous species like C. montana or C. armandii do the job quickly but need significant space. The RHS Plant Finder is a reliable reference for what grows well in the UK without needing a greenhouse.

2. Pick the right position

The classic advice is "head in the sun, feet in the shade" — most clematis prefer their roots cool and their top growth in a sunny or lightly shaded spot. A few are genuinely shade-tolerant, including C. alpina and C. macropetala, which will flower reasonably well on a north wall.

That said, most large-flowered hybrids want at least four hours of sun a day to perform well. Morning sun with some afternoon shade is often the sweet spot in Kent's climate.

3. Prepare the planting hole generously

Dig a hole at least twice the width of the pot and deeper than the rootball — you want the final planting depth to be around 7–10cm below where the plant sat in its pot. This deep planting encourages stems to develop below ground, which means if clematis wilt strikes (more on that below), the plant can regenerate from the buried nodes.

Fork in plenty of organic matter — garden compost, well-rotted manure, or a proprietary planting compost. Clematis are hungry plants and they'll thank you for a well-prepared start.

4. Plant deep and angle the stem toward the support

Lower the plant into the hole so the top of the rootball is around 5–7cm below soil level. Angle the stems gently toward the support structure — trellis, post, obelisk, or whatever it's climbing. Spreading and tying in a few individual stems at the start rather than letting them tangle gives you a much better-shaped plant.

Firm the soil in around the roots, water thoroughly, and then add a layer of mulch around the base — but keep it away from the crown itself. Bark chippings, gravel, or a flat stone over the roots all help keep the root zone cool and moist.

5. Water regularly for the first season

Clematis needs consistent moisture to establish, particularly in its first year. In dry spells, water at the base rather than over the foliage. Once established, most varieties are reasonably drought-tolerant, but they'll always produce more flowers with adequate moisture in summer.

Container-grown clematis needs more frequent watering than border plants — pots dry out quickly in summer and clematis wilts quite dramatically when stressed. Check daily in hot weather.

6. Feed through the growing season

Start feeding in spring when you see new growth, using a high-potash liquid fertiliser — the same kind used for tomatoes works perfectly. Continue every two weeks through the flowering season. Once flowering is over, switch to a balanced feed to help the plant build energy for next year.

Granular slow-release fertilisers applied in spring are a good lower-maintenance alternative if you'd rather not remember to liquid feed every fortnight.

7. Prune according to your group

This is where people come unstuck. Prune a Group 1 clematis hard in late winter and you'll cut off all the flower buds — it won't flower at all that year. Pruning groups are usually on the plant label when you buy it.

Group 1 (spring-flowering — C. montana, C. alpina): prune lightly just after flowering in late spring, removing dead or damaged stems only. Group 2 (large-flowered, early summer): light tidy in late winter, removing dead tips; these flower on old and new wood. Group 3 (late-flowering — C. viticella, C. tangutica and most small-flowered types): cut back hard to around 30cm in late winter. Simple.

8. Deal with clematis wilt promptly

Clematis wilt is a fungal disease that causes otherwise healthy stems to collapse and die back suddenly. It looks alarming, especially in the first year. Cut all affected stems back below soil level, to where the stem looks healthy.

Plants that were deep-planted usually recover and push up new growth from the buried nodes. Dispose of the affected material — don't compost it. Repeat infections in later years are less common once the plant is well established.

When to call a handyman

If you need a trellis, pergola, or support structure built for your clematis to climb, Richard can help with that side of things across Sandwich and East Kent. The growing is all yours — the framework is where a handyman comes in handy.