Clematis need moisture-retentive, but well-drained soil. The herbaceous species prefer full sun, but most climbers and shrub species will thrive in full sun or partial shade.
Keep the base of the plant and the roots cool and shaded by carefully positioning other plants, or put a layer of pebbles or flat stones at the base.
Plant large-flowered cultivars that bloom in May to June with the tops of their root balls 5-8cm (2-3in) below the soil surface. This will encourage shoots to grow from below soil level and also helps the plant to recover if affected by clematis wilt.
Herbaceous and evergreen species such as Clematis armandii and C. cirrhosa should be planted with the crown at soil level.
- Each year, in late winter or early spring, apply a potassium-rich fertiliser (such as Vitax Q4 or rose fertiliser), according to the manufacturer’s instructions
- Mulch immediately afterwards with organic matter such as well-rotted manure, leafmould or garden compost
- Water regularly during periods of dry weather in the first few seasons after planting. Watering to soak the root zone requires at least the equivalent of four watering cans per square metre
Clematis make pretty container plants, especially if trained up an obelisk or small trellis. Choose cultivars such as C.‘Barbara Jackman’, C.‘Miss Bateman', or C.'Bee’s Jubilee’, which are smaller-growing.
Use containers that are at least 45cm (18in) deep and wide and use a soil-based potting compost such as John Innes No 2.
Make sure you water regularly during the growing season and apply a general-purpose liquid fertiliser monthly during spring and summer.
Replace the top 2.5-5cm (1–2in) layer of compost each spring with fresh potting compost. The roots of clematis in containers should be protected both from freezing in winter and baking in summer. Use bubble polythene for winter insulation and shade the pot in summer, perhaps by placing pots of taller plants on the sunward side.