Bothrocaryum controversum Seeds | (syn. Cornus Controversa)

Giant Dogwood (Cornus controversa) with distinctive horizontal tiered branches and flat white flower clusters — Giant Dogwood (*Cornus controversa*): Cornaceae, the wedding-cake tree whose branches stack in perfect layers.

LATIN NAME: Bothrocaryum controversum (syn. Cornus controversa)

COMMON NAME: Giant Dogwood, Wedding Cake Tree

Plant Profile

The Giant Dogwood is a large deciduous tree of the dogwood family from China, Korea, Japan and the Himalaya, and its architecture is the show: the branches carry in flat, horizontal tiers, one storey above another, so that a mature tree looks like a layered cake or a pagoda drawn in green. In early summer the tiers hold flat clusters of small white flowers, and in late summer these become blue-black fruits that birds clear quickly. The leaves turn red and purple in a good autumn, and in winter the bare tiered silhouette keeps the tree’s structure on display.

It reaches fifteen to twenty-five metres in the wild and makes a broad, dignified specimen in gardens, where its layered form is best seen against open space. It is one of the largest of the dogwoods, and one of the most architectural trees of any family.

Science & Biotechnology

Its name carries a running argument: older treatments set it and a few relatives apart in the genus Bothrocaryum, while modern classifications fold it back into a broad Cornus, and the molecular work that reshaped the dogwood family has tested the question repeatedly, making it a small but genuine case study in how DNA data reshuffles familiar genera. The tiered branching that gardeners prize has been noted in plant-architecture studies, which classify such patterns formally and compare them across unrelated families. Its fruits are bird-dispersed, and ecological studies of its East Asian forests record it as an understorey-to-canopy tree of moist mountain woods.

Its variegated sport, the ‘Variegata’ form with white-margined leaves, is one of the most expensive garden trees in the trade, and every plant of it is a propagated clone of a single original find.

Uses & Benefits

In the garden it is a specimen for open space: a lawn tree, a park tree or the quiet star of a winter garden, where the tiered silhouette and the smooth bark carry the display that leaves and flowers provide in season. It needs room to show the layers, and it rewards the long view, since the architecture improves for decades.

The white flower clusters feed bees and hoverflies in early summer, the blue-black fruits feed birds in late summer, and the structure shelters nesting birds through the season. It is a tree whose garden value is shape first, colour second.

Growing from Seed

Give the seed a double winter: sow into a free-draining compost and leave the pots outdoors for two full winters, since dogwood seed germinates irregularly and often waits out a season, or warm-stratify for three months and then cold-stratify for the same before a spring sowing. Keep the trays just moist and shaded.

Grow the seedlings in bright, airy conditions, potting on as the root deepens, and line out for two or three years. Plant out in autumn into deep, moist, well-drained soil in sun or light shade, spacing it for the eventual twenty-metre crown. Water through the first two summers and then let the layers build at their own pace.

Our Take

The wedding-cake tree: horizontal tiers, flat white flowers, blue-black fruit and a winter silhouette no other hardy tree matches. Give it space and a decade, and it repays both.

Tree Seeds