Angelica pubescens Seeds | Du Huo
LATIN NAME: Angelica pubescens
COMMON NAME: Du Huo
Plant Profile
The leaves are large and two or three times pinnate, with broad-toothed leaflets that are smooth above and softly hairy beneath, mounted on long sheathing stalks. Flowering shoots carry compound umbels of many rays, each ray topped by a small umbellet of white flowers, so that the whole head forms the flat platform typical of the family. The fruits are dry schizocarps with winged ribs, and they ripen through late summer into autumn in loose brown pairs.
The finely double-toothed form was long treated as a variety of this species and is now usually separated as Angelica biserrata, which matters to a grower because the two are not identical in root shape or in coumarin content. Seed should be bought under a clear name, and it is worth asking which form a supplier holds before planning a field.
Furanocoumarins intercalate into skin cells and react to ultraviolet light, so anyone handling or processing this root should work with gloves, keep dust away from eyes and sun, and wash thoroughly afterwards. This is ordinary good practice with a chemically active member of the carrot family, not a reason to avoid the plant, but it deserves to be said plainly.
The root is lifted when the stems have yellowed and the crown has stopped pushing new growth, which is also the point at which the coumarin content is highest in most reports. Dig well clear of the plant with a fork and lever rather than pull, because the taproot is long and brittle. Cut the stem an inch or so above the crown, shake off the soil and remove the worst of the fibres.
Wash the root quickly in cold water, never soaking it, then slice it lengthwise into fingers or across into thick discs depending on the market. Dry on racks in a shaded, airy loft until a slice snaps cleanly, and store in a sealed container away from light, since the coumarins degrade with prolonged exposure.
Science & Biotechnology
The root’s value lies in its coumarins, chiefly osthole, a prenylated coumarin that is the usual marker compound, with columbianadin, angelol and a set of furanocoumarins including bergapten and imperatorin close behind. These are the constituents that give the dried root its characteristic aromatic, faintly resinous smell when it is broken, and they are what a buyer’s assay is testing for. Osthole and columbianadin are extracted from milled root with alcohol, and the crude coumarin fraction is what most formulations are built on.
Uses & Benefits
Steam distillation of the milled root gives a heavy, aromatic oil dominated by the coumarins rather than by monoterpenes, and its yield and composition shift noticeably with the age of the root and the time of harvesting. Distillers usually work with material dried slowly in the shade, since high heat drives off the more volatile fraction and darkens the residue. The spent root still carries coumarins and is sometimes used for further solvent extraction rather than being discarded.
Growing from Seed
Pubescent angelica is a robust herbaceous perennial of open, well-drained ground, growing a metre or so tall on hollow, ribbed stems that are covered in short hairs. In the wild it occupies sunny banks, roadside verges and the edges of thin woodland, often on shallow stony soils where its deep taproot can find moisture far below the surface. Unlike the marsh angelicas, it rots in ground that stays wet through winter.
Sow in late summer or autumn, while the seed is fresh, into a gritty mix of two parts coarse sand, one part sieved compost and one part garden loam, set in a frame. Surface-sow thinly, press the seed into contact with the soil and cover it with no more than a dusting of sand, because cool, moist conditions above a well-drained base assist emergence. Leave the frame outdoors through winter and keep the surface damp but never sodden; a cold, wet frame is how most seedings of this family are lost. Prick out seedlings as soon as the first true leaf is fully open, and plant out in autumn when the rosette is a hand across, spacing them half a metre apart in full sun on ground that drains freely.
Aphids gather in the folded young umbels and should be washed off early rather than ignored, and in damp seasons the same crowded heads can carry leaf spot. Thin seedlings and leave air between plants, remove spent stems after seed fall, and avoid planting this one where the soil holds winter water.
Our Take
This is a plant for a hot, stony bank where nothing else is happy, and it asks for nothing more than drainage and sun. Do not confuse it with the damp-ground angelicas: Chinese angelica wants rich, moist soil and a shorter life, while Ashitaba is grown for its leaf rather than its root. The tall, sweet-scented garden angelica is the third member of the genus worth a bed of its own.
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