Alder Buckthorn
Frangula alnus
The finest charcoal for the finest powder. A quiet tree with explosive associations.
Overview
Alder buckthorn is not a buckthorn at all — it lacks the thorns that gave the related purging buckthorn its name — and it is not especially related to alder beyond sharing a preference for wet, acid ground. What it is, specifically, is the preferred source of charcoal for black gunpowder manufacture. The slow-burning, low-ash charcoal produced from its young stems was prized by European powder makers for centuries; the wood that grows quietly at the edge of marshes and wet heathland had a consistent relationship, through the industries of war, with the sudden destruction of things.
Botanical Notes
A deciduous shrub or small tree to 5 metres, with smooth, dark bark marked with orange lenticels and lacking the terminal spines of the true buckthorns. Leaves alternate, oval, with prominent parallel veins. Flowers small, greenish-white, from May to June. Berries 6–10mm, ripening from green through red to deep purple-black in August–September. Found on wet, acid, peaty soils — carr woodland, fens, bogs, and damp heathland — throughout Europe. Closely related to purging buckthorn (*Rhamnus cathartica*), which shares the purgative character of the berries but grows on dry calcareous soils rather than wet acid ones. The bark and berries contain anthraquinone glycosides (frangulin and related compounds) responsible for the purgative action.
Lore & History
The charcoal association was specific and long-standing: gunpowder manuals from the sixteenth century onward specify alder buckthorn as producing the most even-grained, best-burning charcoal for serpentine powder. The wood was coppiced for this purpose in the forests of southern England and exported to powder mills across Europe. That a plant of unassuming marshland should have been, for several centuries, a critical industrial material for the manufacture of explosives has the quality of a dark joke the plant never bothered to explain. The berries, meanwhile, were used as a dye — green from unripe, blue-grey from ripe — and the powdered bark was among the standard purgatives of pre-industrial European medicine, described without enthusiasm by every herbalist who encountered it.
Warnings
The fresh bark and berries are strongly purgative and can cause severe gastrointestinal pain, vomiting, and bloody stools. The bark must be dried and aged for at least one year before medicinal use — fresh bark is far more violent in action. Ripe berries are particularly purgative; even a small number cause significant distress. Children should be kept from the plant during berry season. Do not use in pregnancy. The charcoal itself is inert and safe.