Clematis Growing Guide

Many Clematis species and hybrids, Clematis montana and Clematis x jackmanii

Clematis

Crop Rotation Group

Miscellaneous ●

Soil

Fertile, well-drained soil enriched with plenty of compost.

Position

Full sun to part shade. Clematis are often grown near structures that provide some shade. When siting a clematis, look for a spot where the mature vine will have its feet in the shade, and head in the sun.

Frost tolerant

Cold hardiness varies with cultivar, with many clematis hardy to -34°C (-30°F), Some evergreen species grown in warm climates are much less tolerant of cold.

Feeding

In early spring as new growth emerges, mulch over the root zones of the plants with rich compost or rotted manure.

Spacing

Single Plants: 1.00m (3' 3") each way (minimum)
Rows: 1.00m (3' 3") with 1.00m (3' 3") row gap (minimum)

Sow and Plant

Plant dormant roots from autumn through to spring, as long as your soil is not frozen. Container-grown plants can be set out until early summer. Enrich the planting hole with plenty of compost, and set the plant deep, so the top of the root mass is covered with at least 5cm (2 inches) of soil. With clematis, deep planting encourages the development of multiple branches. Be patient with newly-planted vines. There is a saying about clematis: The first year they sleep, the second they creep, and the third year they leap. Leave 2 m (6 feet) between plants when multiple clematis are planted on a fence or wall. Most clematis are grown as single specimens trained up a post or trellis. In containers plant 1 plant per 35 cm (14-inch) wide pot. Choose dwarf clematis varieties for containers.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.

Notes

Intensely hybridised for the last 200 years, large-flowered clematis are available in an endless array of colour combinations and forms. They are the perfect vines for training on a pillar. Bloom times vary, and most cultivars tend to bloom all at once. Most gardeners choose large-flowered hybrid clematis because of their mesmerising show of huge blossoms, but there also are species native to almost every temperate climate. In the UK, native Clematis vitalba, old man’s beard or traveller’s joy, is a common site in autumn hedgerows. In the US, native Clematis virginiana, virgin’s bower, is quite similar. There are many other native species worthy of consideration. Most cultivated clematis require moderate pruning, which varies with the plant’s bloom time. If an overgrown plant needs pruning, you can never go wrong by doing it after flowering ends. New growth will then be directed toward new buds for the following season. Trim off dead or damaged branches in spring, taking care to avoid cutting back bud-bearing branches. The best way to propagate clematis is to root stem cuttings taken in summer, after the flowers fade. Some cultivars root readily, but it’s still a good idea to root twice as many cuttings as you hope to grow.

Harvesting

Despite having short stems, clematis make beautiful additions to summer flower arrangements. Cutting blossoms may help extend the bloom time of some varieties.

Troubleshooting

Clematis may have passing problems with powdery mildew, but the most devastating problem is a fungal disease called clematis wilt. The disease is most severe on young plants. Branches or entire plants collapse and turn black within a few days. When the dead plant is pruned off at the ground and removed, affected clematis may make good regrowth from the roots.

Planting and Harvesting Calendar

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Pests which Affect Clematis