Laburnum (commonly called golden chain) is a genus of two species of small trees in the subfamily Faboideae of the pea family Fabaceae, Laburnum anagyroides (common laburnum) and L. alpinum (alpine laburnum). They are native to the mountains of southern Europe from France to the Balkan Peninsula.
The trees are deciduous. They have yellow pea-flowers in pendulous racemes 10–30 cm long in spring, which makes them very popular garden trees.
Most garden specimens are of the hybrid between the two species, Laburnum × watereri (Voss’s laburnum), which combines the longer racemes of L. alpinum with the denser flowers of L. anagyroides; it also has the benefit of low seed production.
All parts of the plant are poisonous, and can be lethal if consumed in excess. Symptoms of laburnum poisoning may include intense sleepiness, vomiting, convulsive movements, coma, slight frothing at the mouth and unequally dilated pupils. In some cases, diarrhoea is very severe, and at times the convulsions are markedly tetanic. The main toxin in the plant is cytisine, a nicotinic receptor agonist. It is used as a food plant by the larvae of some Lepidoptera species, including the buff-tip.
The heart-wood of a laburnum may be used as a substitute for ebony or rosewood, very hard and a dark chocolate brown, with butter-yellow sapwood.
Laburnum has historically been used for cabinetmaking and inlay, as well as for musical instruments. In addition to such wind instruments as recorders and flutes, it was a popular wood for Great Highland bagpipes before taste turned to imported dense tropical hardwoods such as cocuswood, ebony, and African blackwood.
Thorp Perrow is very proud to hold the national collection of Laburnum and many of our Laburnum are also Champion Trees.