Clematis trichotoma

Clematis trichotoma, called trichotomous clematis or fragrant Korean clematis, is a botanical species still uncommon in gardens. It charms with its clusters of white, single, light flowers, whose fragrance recalls mock orange. This summer clematis is suitable for climbing on large supports: wire fence, large trellis, pergola or small tree. It has a less wild and less exuberant appearance than the hedgerow clematis, while showing interesting vigour.

This species belongs to the family Ranunculaceae. It is simply called trichotomous clematis or fragrant Korean clematis. The name Clematis vitalba ‘Trichotoma’, sometimes encountered in the trade, is not botanically correct: it is not a cultivar of Clematis vitalba, but a distinct species, Clematis trichotoma, described by Nakai in 1912. It is native to Korea, where it grows in open woods, shrubby areas and rocky slopes, in a temperate climate. It is a deciduous woody vine: its stems persist from year to year, but its leaves fall in autumn. It climbs without the aid of climbing roots or suckers; the leaf petioles twine around a support. In cultivation, in our climates, it reaches 3.50 m to 5 m in height for 1.50 to 2 m in spread. Older specimens can exceed these dimensions if allowed to run into a hedge or tree. The leaves, a fresh green, are composed of five ovate to broadly ovate leaflets, sometimes weakly lobed. Flowering appears between June and September and may continue into early autumn depending on the climate. The flowers, grouped in cymes, measure 2.5 to 4 cm in diameter. They bear four to six white, well-opened tepals around a cluster of long, pale stamens. Their scent is one of the most pleasant and strongest to be found among small-flowered clematis. After flowering, fruits called achenes are formed, extended by long, feathery, silvery styles. This species is not listed as susceptible to diseases. Like other clematis, it can suffer from stem dieback in waterlogged soil, in too hot a situation or after water stress.

In the garden, give this clematis a large support. It can accompany a vigorous climbing rose, provided they are not planted too close together. The climbing rose ‘Sympathie’ is interesting for its vigour and red summer flowering, as well as the Clematis viticella ‘Étoile Violette’, robust and floriferous. To shade its base, choose sturdy plants that cover the ground without competing with its roots, for example Epimedium perralchicum ‘Frohnleiten’, Geranium nodosum or Bergenia cordifolia.

Advice: avoid excess fertiliser which stimulates foliage to the detriment of flowers. Do not mulch, to avoid excess moisture which favours clematis wilt.