Clematis Care Guide

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At Thorncroft Clematis we have been growing clematis and climbers since the 1960's when my Grandparents first started gardening.

Here is an opportunity for us to pass on some of our best advice on how to succeed with them in your garden, knowledge honed over the decades.

The care of clematis is a big subject so click on the links below to skip to the parts you will find most useful.

Planting in the Ground

Careful planting is the key to success!

When is the best time to plant a clematis?

With the quality of the clematis we supply you are able to plant year round so long as the ground is not waterlogged or frozen solid and so long as the plant has had a period of 'hardening off'.
We always recommend improving the soil, whether it is sandy, moderate or clay so you will have ample opportunity while preparing the planting hole, to establish if the ground is in a fit state to receive it's new plant.

Hardening off (November to the end of April)

Clematis purchased during winter through to May, must be hardened off before planting. Stand the plant outside in a sheltered position during the day but take into unheated cover overnight. An unheated greenhouse, conservatory or even a garage will be sufficient to prevent frost damage to the soft growth. The process should be continued for about two weeks before planting.

Planting Clematis in the Garden

The key to successful clematis growing is careful attention to the planting and soil improvement. Without proper soil preparation, even the best quality plants will not thrive or perform to their very best in your garden. An important thing to remember is that clematis like a soil which holds good nutrient but a soil that drains well, so that they do not become too wet.

1. If planting by a wall or fence - the hole should be dug approx. 12" (30cm) away from its base.
2. If planting by a tree - plant about 2 feet (60cm) away from the trunk leaning the cane of the clematis towards the support, try to plant on the north side where the host plant will then shade the root system of the clematis.
3. If planting to grow into a shrub - dig the planting hole just outside the ‘drip-line’ - this is outside the outer branches and lean the bamboo can into the shrubs lower branches.

Whatever your soil type, whether it is heavy or light, acid or alkaline, it should be improved before planting. A clematis does not need a particular soil pH, just good soil quality.

Clematis Planting method:

To start with water the clematis thoroughly before planting, maybe let it soak in a bucket of water but only while you prepare the hole.

1. Dig the planting hole much bigger and deeper than the size of the flower pot. 18”(45cm) diameter and depth is ideal.
2. Break up the soil in the bottom of the planting hole and add well rotted garden compost or a good quality bag of compost. The best compost for clematis is John Innes No.3 because this is loam based and has a high food content. Compost for clematis needs to hold good nutrient as well as adding it.
3. If using manure, put a layer in the bottom of the hole, fork in well and cover with at least 2" of soil. Make sure it is rotted well and not hot or steaming.
4. Sprinkle one good single handful of bonemeal into the hole and mix into the loosened soil. We stock Bonemeal in a 1.5kg Box.
5. Take the plant from the bucket of water (keep this water for later) and remove the plastic ties from the bottom 6 inches of the plant.
6. Remove the pot then carefully loosen the roots if they are in a tight ball. This is essential to encourage good rooting and breaking some of the roots is not a problem, this will aid the development of new root growth.
7. IMPORTANT - Place the plant carefully in the hole making sure that the top of the root ball is buried about 3” (8cm) deeper than it was in its pot and re-fill the hole with a mixture of soil and compost, firming down by hand.

8. Next place a small handful of Westland Gro-Sure Slow Release Plant Food around the base of the plant and gently wriggle it into the soil enough to cover it up.
9. Using the remaining water from your bucket, water thoroughly - especially if your soil is light and very free draining. Clematis planted by a wall, fence, tree or shrub, may need regular watering especially in its first year but be careful not to overdo it if planting in the autumn.

If your clematis is planted in a hot position, where the base of the plant will be baked by the sun for a large part of the day, place bark chippings or mulch around the base to provide shade for the root system. This will help to keep the roots cool and moist avoiding the plant drying out so quickly.

We stock a range of useful products which you might need when planting your clematis or when preparing the planting area. Check out what we have to offer including our popular range of Care Packs right here in the Plant Care & Gifts section.

Planting in Containers

Choose a large container, preferably terracotta not plastic, at least 18"(45cm) deep with adequate drainage holes. Put plenty of crocks, stones or gravel in the bottom to ensure good drainage and stand the container on feet or bricks to stop the drainage holes becoming blocked.

The best clematis compost is John Innes No.3 mixed with a good multi-purpose compost about 3 parts John Innes to 1 part multi-purpose. Plant the top of the clematis root deeper in the new container by about 3 inches.

Check container grown plants regularly for watering needs, however be careful not to keep them too wet over the winter, and ensure the pot is draining freely!

Each February remove an inch or two of compost from the top of the pot and replace with fresh compost to which a single handful of bonemeal has been added, and water in. For the best results, put a small handful of Westland Gro-Sure Slow Release Plant Food into the pot in March, then from April to the end of September we recommend sprinkling on a small handful of Westland Sulphate of Potash about once every 3-4 weeks.

Every four to five years root pruning may be necessary. During winter time when the plant is dormant take the pot off and cut away 2" - 3" of root from the outside of the root-ball. Cut one third off the bottom, and re-pot with fresh John Innes No.3 compost.