Campsis, or trumpet vine as it is commonly known, is a self-clinging climber grown for its clusters of showy, exotic orange to red or yellow, trumpet-shaped flowers.
Campsis are vigorous, deciduous, woody-stemmed climbers, clinging by means of small aerial stem roots.
They are grown for their handsome, ash-like leaves and the bold terminal trusses of orange to red, trumpet-shaped flowers up to 8cm (3in) across, produced on the current season’s growth from late summer to autumn.
Site and soil conditions
Grow Campsis against a warm sunny wall at least 4m (13ft) high. Although hardy, they need shelter from cold winds, and they need full sun to ripen the wood if they are to flower freely. Campsis do well in any moderately fertile, moist but well-drained soil.
Watering and feeding
Campsis generally need little additional feeding unless they are grown in very nutrient-poor soils (such as shallow chalky soil), or in containers. Feed with a general purpose fertiliser such as Growmore or fish, blood and bone, scattered at the base in early spring at a rate of about 70g per sq m (2oz per sq yd). Container-grown plants can be fed with a liquid feed such as tomato fertiliser.
Campsis is fairly drought tolerant, but newly established plants and container-grown specimens should be watered in dry spells. Even well-established plants will perform better if watered during prolonged periods of drought.
Grow in loam based potting compost such as John Innes No 2 potting compost. Multipurpose compost can also be used. Extra perlite or grit may be added to improve drainage.
Pruning and training
Campsis are self clinging climbers using aerial roots to attach their long stems, although Campsis grandiflora is best tied in to supporting wires. It takes two or three years to establish a strong woody framework of branches before plants begin to flower well.
Training a young plant
The aim is to produce a framework of stems from which flowering shoots emerge each year.
After planting, cut back all the stems to 15cm (6in) from the ground to stimulate new growth. Train the strongest new shoots to fill the space, according to our advice on training and pruning climbers on planting. Always remove weaker shoots.
Pruning an established plant
Once a framework is established, usually in two to three years, spur-prune sideshoots annually in late winter. This involves cutting back sideshoots to within two or three buds of the main stems. Remove any weak growth and cut back damaged stems close to the base.
Renovating an old plant
Hard pruning will reduce flowering, but can be used to renovate an overgrown plant. Cut back all shoots to within 30cm (12in) of the base in late winter and train in the strongest of the new shoots as for a new plant.
Campsis can be propagated from seed, layering, semi-ripe, hardwood and root cuttings.
Rooted suckers can be severed from the parent plant and potted up on their own to grow into plants that are big enough to plant out in the garden.
Sow seed in autumn in containers of John Innes or other seed compost placed in a cold frame.
C. grandiflora: The hardiest species, with deep orange to red flowers with a yellow throat up to 8cm (3in) across and leaves to 30cm (1ft) long; it may need tying in to supports.
C. radicans: Slender orange to red flowers, and leaves to 10cm (4in) long; completely self-clinging once established.
C. radicans f. flava AGM: As for C. radicans but with yellow flowers.
C. × tagliabuana ‘Madame Galen’ AGM: Orange-red trumpet-shaped flowers and leaves to 30cm (1ft) long.
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Bud drop may occur due to low temperatures or dryness at the roots, but other than that Campsis are relatively trouble free but can be affected by a few pests and diseases listed such as powdery mildew, aphids, mealybug
and scale insect.