How do I stop my clematis being bare at the bottom?

The bare-legged clematis with a tangle of flowers at head height is the standard outcome of leaving the plant to its own devices. Clematis climb by twisting their leaf stalks around thin objects, and left alone they all head for the light in one bundle, abandon the lower part of the stem, and produce a plant that flowers at the top of a bare stick.

What you'll need

• Plastic-coated mesh, netting or thin horizontal wires
• Soft ties or twine
• Secateurs
• Twiggy pea sticks for the first metre (optional)

Step by step

1. Check the support will actually work.A clematis grips with twisted leaf stalks that can only close around something a few millimetres across. Wide trellis battens, a fence panel, a thick post or a bare wall are all ungrippable. Add plastic-coated mesh, netting or a grid of thin wires and the problem often solves itself.
2. Identify the pruning group, because it changes the answer.Group three — those flowering from July onwards — are cut hard to 200 to 300mm above ground every late winter, so they cannot become bare-legged. If your bare clematis is one of those, the fix is simply to start pruning it. Groups one and two need training instead.
3. Spread the stems out horizontally rather than letting them bunch.Tie the young stems out sideways across the support in a fan, as widely spaced as you can, rather than allowing them to climb as a single rope. Every stem trained sideways produces side shoots along its length.
4. Weave stems back downward in spring.On a group two clematis, take some of the long stems and gently spiral them down and around the lower part of the support before letting them climb again. Do this in early spring while the growth is still flexible; later in the season the stems snap.
5. Cut alternate stems shorter in late winter on a group two.Rather than pruning every stem to the same height, cut some back to about 300mm and leave the others long. The short ones flower low, the long ones flower high, and the plant fills the whole support.
6. Plant something in front of the base.The traditional solution, and it works. A low shrub, a group of perennials or a hardy geranium at the foot of the plant hides the bare stems and shades the roots at the same time, which the clematis wants anyway.
7. Grow it through a shrub or another climber.Clematis are naturally scramblers through other plants. A viticella clematis grown through a large shrub or up an established climbing rose covers its own bare legs entirely and often flowers when the host has finished.
8. Feed and mulch so it produces growth from low down.A hungry clematis makes one weak stem. Compost mulch each spring and a high-potash feed through the growing season produce several strong stems from the base, which is the real long-term cure.
9. Renovate a hopeless case by cutting it hard.Group three: cut to 300mm in late winter, no risk. Group two: cut to about 450mm in late winter, accepting the loss of one year's early flowers, and train the regrowth properly. Group one — montana and its relations — cut only after flowering, and accept that a montana renovated hard may take two or three years to flower again.

Tips

• Do the training in early spring when the stems are pliable. Clematis stems are notoriously brittle in full growth and snap at the joint if handled in summer.
• The first metre of a clematis is the hardest to cover. Pea sticks or twiggy hazel pushed in around the base give young stems something to hold at the level where mesh is often not fitted.
• Grown through a wall-trained rose, a viticella clematis extends the flowering season on the same square metre of wall by two months. Both are pruned in winter, which makes them easy companions.
• If a clematis grows away vertically before you get to it, do not force it back — untangle in spring, when the growth is young and flexible.

Common mistakes

• Blaming the plant when the support is wrong — A clematis cannot hold a fence panel, a thick trellis batten or a bare wall. It is not a vigour problem and no amount of feeding fixes it.
• Trying to retrain stems in midsummer — They snap. All clematis retraining happens in early spring while the growth is soft.
• Never pruning a group three clematis — It becomes a bare tangle with everything at the top within three or four years. These types are designed to be cut to near ground level annually.
• Cutting every stem to the same height — You get a single flowering band. Varying the cut heights gives flowers at several levels.

Questions people ask