Botanical Name: Laburnum
Common Names: Golden chain or Golden rain,(In Bengal it is called Sonajhuri)
Habitat: Laburnum is native to the warm regions of Australia and Africa. Many of the Australian and North American species previously called Cassia have been reclassified to the genus Senna. However, these plants are still widely sold in our local plant nurseries under the scientific name of Cassia.
The Laburnum trees are deciduous. The leaves are trifoliate, somewhat like a clover; the leaflets are typically 2–3 cm (0.8–1.2 in) long in L. anagyroides and 4–5 cm (1.5–2 in) long in L. alpinum.
They have yellow pea-flowers in pendulous leafless racemes 10–40 cm (4–15.5 in) long in spring, which makes them very popular garden trees. In L. anagyroides, the racemes are 10–20 cm (4–8 in) long, with densely packed flowers; in L. alpinum the racemes are 20–30 cm (8–12 in) long, but with the flowers sparsely along the raceme. The fruit develops as a pod and is extremely poisonous.
The yellow flowers are responsible for the old poetic name ‘golden chain tree’ (also spelled golden chaintree or goldenchain tree).
Laburnum species and hybrids are cultivated as ornamental trees for gardens and parks. They are also trained as espaliers on pergolas, for ceilings of pendant flowers in season. In its natural form, Laburnum is a shrubby, multi-branched tree, but it is often pruned to maintain a single trunk which displays the smooth green bark.
Gardeners are advised to remove the spent seedpods after flowering because they sap the strength of the tree and are the most poisonous part. Generally Laburnum does not perform well in hot climates, and has a reduced life-span if grown in climates with warm winters. Afternoon shade and the occasional deep watering are advisable in areas with hot, dry summers. They do best in climates with moderate winter and summer temperatures, ideally Oceanic climates like those of the Pacific Northwest and Northern Europe. Laburnum trees are ubiquitous in England, Wales, Scotland and Ireland, where they are commonly planted as lawn specimens or in shrub borders.
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 Brya ebenus (cocus wood), ebony, and Dalbergia melanoxylon (African monkeywood). The heart-wood of a laburnum may be used as a substitute for ebony or rosewood. It is very hard and a dark chocolate brown, with a butter-yellow sapwood.
Known Hazards: All parts of the plant are poisonous, although mortality is very rare. Symptoms of laburnum poisoning may include intense sleepiness, vomiting, convulsive movements, coma, slight frothing at the mouth and unequally dilated pupils. In some cases, diarrhea is very severe, and at times the convulsions are markedly tetanic. The main toxin in the plant is cytisine, a nicotinic receptor agonist.
Disclaimer : The information presented herein is intended for educational purposes only