When to plant clematis?
- Botanical name
- Clematis
- Family
- Ranunculaceae
Clematis is planted from September to May.
Clematis is a woody perennial.
The time of flowering tells which wood a clematis carries its flowers on, and the pruning follows from that. Varieties that flower in spring carry the flowers on last year's shoots and need no regular pruning, only the faded flowers are taken off. Varieties that flower in early summer carry them on short shoots from last year's growth, so they are cut back to a strong pair of buds. In those that flower in late summer the flowers form on this year's shoots, so they are pruned hard. Left uncut, those last ones flower higher every year and leave bare stems below.
A clematis in deep shade flowers poorly, so the site chosen for it is in sun. The roots at the same time need cool, moist soil, so the base is covered, with perennials or with a layer of pebbles.
Cutting brings sap out of the stems, and it contains protoanemonin. On the skin it causes a rash.
Clematis through the year
- planting
- pruning (spring-flowering)
- pruning (early-summer-flowering and late-summer-flowering)
In short
Growing conditions
Is clematis toxic to cats and dogs?
Yes. Toxic to people and animals, toxic parts: leaves and sap.
Pests and diseases
Listed here is every problem for which the sources name this plant as a host. The problems are not listed in order of how common they are.
- Signs
- Colonies of small aphids sit on the shoot tips and the underside of the leaves. The leaf curls and puckers, and sticky honeydew is left on everything below. The viruses they carry are more dangerous than the feeding itself.
- Prevention
- Go easy on nitrogen, because soft sappy growth is what aphids are looking for. Encourage the predators (ladybirds, lacewings, parasitic wasps). Use a reflective mulch, which puts them off settling, and a strong jet of water to knock the colony off the tips.
- What to do
- Potassium soap works on contact and only while it is wet, so it has to reach the underside of the leaf. On drought-loving plants and in heat it can scorch, so apply it in the evening.
- Signs
- A shoot wilts and blackens suddenly, often just before flowering and without any gradual decline. Cut across, the stem is dark inside. The root usually survives and new healthy shoots come from the ground or just above it.
- Prevention
- The disease hits the large-flowered hybrids above all. The species with small flowers are considerably tougher. Resistant or tolerant are Clematis alpina, C. montana, C. viticella, C. macropetala, C. tangutica, C. orientalis and C. integrifolia. Deeply worked and mulched soil, which saves the roots from drought stress, lowers the risk.
- What to do
- Cut the wilted shoots back to healthy, unstained tissue and remove the cuttings at once, so that they do not infect the soil. Do not dig the plant out too soon, because new growth often comes from ground level.
- Signs
- A white, floury coating spreads over the leaves, first on the lower and older ones. The leaf under it yellows and dries up. The fruit stays small, because the plant loses leaf surface.
- Prevention
- Plant resistant varieties, leave an airy spacing and sun, and clear the debris at the end of the season. Unlike most fungi it is not helped by wet foliage, since it spreads in heat and high air humidity, in a dry summer too.
- What to do
- Oil products meant for powdery mildew on the squash family work on contact. They do not cure a leaf that is already affected, but they stop the spread to healthy ones. On herbs cut the affected shoots back instead, since the new growth comes clean. On ornamental perennials what is left is spacing and moisture.
- Signs
- The half round notches along the leaf edges in summer are the work of the adult beetles and do the plant little harm. The larvae are the danger: white grubs with a brown head eat the roots, the plant suddenly drops its leaves and dies, most often between autumn and spring.
- Prevention
- Most at risk are plants in pots and troughs. In a bed the damage is rarer. At repotting check the roots and the compost and pick the larvae out. You find the adult beetles in the evening with a light, when they crawl over the plants.
- What to do
- Pick the adults off in the evening, set sticky traps indoors and change the compost, removing the larvae as you go. There is no insecticide. As biological protection, water beneficial nematodes into the compost at the end of summer, while the larvae are still small.
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Related plants
The plant below is in the same botanical family (Ranunculaceae).
Sources about the plant: ASPCA Toxic and Non-Toxic Plants, GBIF Backbone Taxonomy, NC State Extension Plant Toolbox, Royal Horticultural Society, Wikidata. Checked between 14 and 28 August 2026. The problem descriptions also draw on: Clemson Cooperative Extension, KGZS, UF/IFAS Extension, University of Illinois Extension, University of Maryland Extension, University of Wisconsin-Madison Division of Extension, Utah State University Extension.