Disanthus cercidifolius Seeds | Disanthus
LATIN NAME: Disanthus cercidifolius
COMMON NAME: Disanthus
Plant Profile
The shrubs grow as broad, rounded mounds two to four metres high, with grey-brown bark that stays smooth on young wood and splits lightly with age. Flowering starts before the leaves have fallen, which is where this species parts company with its winter-flowering relatives: the witch hazels hold their ribbon petals until the foliage is gone, while Disanthus opens against a still-full canopy.
The leaf is the easiest way to place the species. It is nearly circular to kidney-shaped, six to ten centimetres across, with five to seven principal veins radiating from the base rather than running down the blade, and a long leaf stalk. Most of the witch-hazel family carries toothed edges; this genus is one of the few with an unbroken margin, so a torn leaf is the exception rather than the rule. The underside shows fine veins and scattered hairs under a lens, but no dense felt.
Two flowers share a single stalk from the previous season’s wood, which is why the blooms appear in the axils instead of at the tips. Each has five narrow, recurved petals in a dark oxblood red, five stamens, and a small cup of nectar at the base that keeps late hoverflies visiting after most garden flowers have finished. The fruit is a woody capsule with two short horns, holding two glossy black seeds, and it browns and splits along its length when ripe.
Garden use is almost entirely ornamental, and almost entirely a question of siting. Plant it where the autumn display is seen straight on, at a path corner or below a window, because the colour reads best in dappled light and goes dull in deep shade. Give it the soil the family prefers: a cool, humus-rich, lime-free loam under deciduous trees, with a mulch of leaf mould that never quite dries.
Science & Biotechnology
The family is chemically remembered for witch hazel distillate, and the tannin chemistry behind it runs through the whole of Hamamelidaceae. Leaf tissue of this genus is astringent in the hand, carrying hydrolysable gallotannins and ellagitannins of the same class as hamamelitannin, along with gallic and ellagic acids released as the tissue breaks down. The crimson of autumn is a separate matter: anthocyanin pigments are laid down in the cell sap as chlorophyll is withdrawn, and here they build up while the flowers are still open.
Clonal propagation follows the standard woody-shrub route. Axillary buds taken from semi-mature wood are started on a basal salt medium carrying 6-benzyladenine as the cytokinin, with an auxin such as indole-3-butyric acid or naphthaleneacetic acid supplied at the rooting stage. Softwood cuttings and simple layering work as well, which matters here because the capsules hold only two kernels and seed lots are always small.
Uses & Benefits
Molecular work places the genus in its own tribe, set well apart from the witch hazels and the winter hazels. That isolation is why the flowers have no close lookalike: nothing else in the family combines an entire leaf with paired blooms. Modern classification puts Hamamelidaceae in Saxifragales rather than among the rosid trees it was once grouped with, which is why the ornamental companions that suit it — witch hazels, winter hazels, sweet gums — sit in several different families in the older literature.
Growing from Seed
Collect the capsules just as they brown, and take the seed out before they split. Sow while it is fresh, because the coat hardens in storage, placing each kernel on edge about its own thickness deep in a mix of two parts leaf mould, one part loam and one part grit, then top with fine grit so seedlings lift cleanly. Keep the pan shaded, moist and cold through winter. The first shoot raises two seed leaves; true leaves follow as a rounded, entire pair that looks like a small copy of the adult blade.
Lift the seedlings when each carries two true leaves, holding the leaf rather than the stem, and pot them singly into lime-free compost cut with a third grit. A young plant is ready for open ground at about thirty centimetres high, and spring planting gives the roots a whole season before winter. Slugs are the main enemy in the seed bed, and there is no serious disease problem.
Our Take
This is a plant for one moment of the year, done properly. Put it where you will see it when the leaves turn, keep it out of limy soil and midday sun, and it will out-colour nearly everything else in the bed. If you want the family together, Chinese witch hazel covers winter and winter hazel covers early spring, while Chinese sweet gum and Cercidiphyllum japonicum work the same autumn trick with far larger leaves.
Related Reading
More species in the same orbit as Disanthus: