Campsis is the botanical name of the trumpet vines, twining or self-clinging climbers with clusters of trumpet-shapedin late summer or early autumn. In warm, sunny, sheltered places they can be spectacular, but they are unsuitable for cold gardens, partly because much growth may be killed by frost, but even more because flower buds may form so late in the season that they have no chance to open. The best place for them is against a wall facing south or west. Each spring most of the old should be cut out or shortened as the best flowers are borne on young growth.
The hardiest and most self-clinging kind is Campsis radicans, with orange-scarlet flowers. C. grandiflora has larger orange and red flowers but is only partially self-clinging and this is also true of Madame Galen, the fine salmon-red hybrid between these two species.
The campsis, or trumpet vine, is a deciduous shrub producing orange and red trumpet flowers in August and September. It grows up to 12 m (40 ft) under ideal conditions and will climb a wall by means of its tiny aerial.
C. radicans is the most common species, and the hardiest.
C. grandiflora, also known as C. chinensis, is more difficult. It needs a warmer site, is not always self-clinging, and is less vigorous, but its flowers are better, with a more definite trumpet shape.
General care: To give of its best, campsis needs a sunny, warm, sheltered site and a humus-rich, well-drained soil. Plant out in the winter, and cut back to a few centimetres from the soil to encourage plenty of growth from the base. Protect from frost. The plant will have to be tied to the wall until it produces its own aerial shoots. Once it is established on the wall, campsis has to be pruned every winter to encourage the flowers: cut back the previous season’s growth to within a few buds of the old wood. The flowers appear at the end of the current season’s shoots.
Propagation: Campsis propagates readily in a number of ways:
1. Fromsown in mid-March in the .
2. Bylong shoots in the autumn and separating them from the parent a year later.
3. From semi-hardwoodtaken in August and grown in a cold frame.
Pests and diseases:attack tender young shoots, causing flower loss. Spray with dimethoate (systemic), formothion (which can be watered in and taken up by the ), malathion and menazon (systemic).
Flower bud drop is caused by low temperatures and dry roots. Guard against the latter by a generous mulch.