Erythrophleum fordii Seeds | Iron Wood

Iron Wood (Erythrophleum fordii) with fine twice-divided leaves and dark woody pods on a tall evergreen tree — Iron Wood (*Erythrophleum fordii*): Fabaceae, the endangered timber giant whose bark carries a poison’s history.

LATIN NAME: Erythrophleum fordii

COMMON NAME: Iron Wood

Plant Profile

The Iron Wood is a tall, slow, evergreen tree of the pea family from the lowland forests of southern China and northern Vietnam, growing twenty to thirty metres with a straight, heavy trunk and a crown of fine, twice-divided leaves. Its timber is the point: dense, dark, and so heavy it barely floats, it has been the prized structural wood of the region for centuries, cut for bridges, wharves, temples and the frames of buildings meant to outlast their builders.

The species is now endangered in the wild, its old-growth stands reduced to fragments, and every established tree carries both the timber value that nearly finished it and the conservation weight that now protects it. The small flowers open in spikes, and the flat, woody pods carry hard, disc-like seeds.

Science & Biotechnology

The genus carries a darker fame than its timber: several of its African relatives are the ordeal-poison and arrow-poison trees, whose bark is charged with erythrophleine and related cardiac glycosides potent enough to stop a heart, and the chemistry has been studied clinically as well as ethnographically, with derivatives of the compounds investigated for cardiac medicine. This species shares the family trait, and its bark and seeds carry the same glycoside load, which places it firmly outside any herbal or food use and inside the pharmacology literature. Its conservation status is the other scientific file: field surveys across its fragmented range have documented the decline that earned it an endangered listing, and restoration plantings in Vietnam and China now work from seed orchards.

Botanically it sits in the Detarieae group of the legumes, and its nodulation, like that of many of its relatives, is limited, which shapes the forestry practice around it.

Uses & Benefits

Its timber record is the region’s own: heavy construction, marine pilings, temple columns and fine furniture, woods whose density resists rot and borers in ground contact and water. In cultivation it is a stately, slow shade tree for large warm gardens and for the restoration plantings that are its species’ best hope, and its place in any garden plan is ornamental and conservation-minded only.

Every part of the tree outside the timber is chemically armed, and no folk use of bark, leaf or seed is safe or recommended. Its story is timber, toxicology and conservation, in that order.

Growing from Seed

Nick the hard seed coat with a file or pour boiling water over the seed and soak overnight, then sow into a deep, free-draining mix at 25 to 30 °C; germination follows within one to two weeks and the seedlings push a strong stem. Grow them in full sun with steady water, potting on as the root deepens.

Plant out into deep, well-drained soil in full sun in a frost-free climate, spacing for a thirty-metre future, and water through the first two dry seasons. Growth is slow and steady; the tree is a century-scale project, and in restoration plantings that is precisely the point.

Our Take

A slow, iron-dense timber tree, endangered in the wild and chemically armed against casual use. For warm gardens it is a stately conservation planting; for forestry, a legacy.

Tree Seeds