Laburnum Tree – General Information
Despite being extremely poisonous the Laburnum tree is very popular for its beautiful display of golden yellow flowers that hang down in racemes in the spring, leading to it often being referred to as a Golden Rain tree and it is used as an ornamental tree in gardens or trained over arches and pagodas.
The Laburnum tree is not native to the United Kingdom, originating from the mountainous regions of southern and central Europe and arrived in Britain sometime in the latter part of the 16th century.
There are three species of Laburnum tree in the United Kingdom, Common Laburnum (Laburnum anagyroides), Scotch Laburnum (Laburnum alpinum) and the most popular variety today, Voss’s Laburnum (Laburnum x watereri). Voss’s Laburnum is a hybrid between the common Laburnum and the Scotch Laburnum, produces the thickest and longest display of flowers but does not produce as many of the poisonous seeds as the other two varieties, making it slightly less attractive to children.
Description of a Laburnum Tree
The Laburnum is a small, deciduous tree growing to about 30 feet tall and with a narrow trunk, making it very popular for the small garden. They have a smooth, olive green coloured bark and leaves made up of three leaflets which are a pale green in colour.
The flowers, which appear in about May are a beautiful yellow colour, are pea shaped (the Laburnum is a member of the pea family) and grow on long, pendulous racemes. The flowers contain both male and female reproductive organs but are still pollinated by insects.
As with any plant from the pea family their fruits are borne in pods which are a light green in colour, turning brown when they start to ripen during July to August. These pods twist and split when they have ripened pushing out their seeds. The seeds are brown on the Scotch Laburnum and black on the common Laburnum and remain on the tree through the winter.
All parts of the Laburnum tree are deadly poisonous including the flowers, leaves, roots, bark and of course the seeds which are sometimes eaten by young children. Some of the symptoms of poisoning are severe diarrhoea, convulsions, vomiting and sleepiness, usually caused by the main toxin cytisine, which can prove fatal if large amounts have been consumed.
Cultivation of the Laburnum Tree
Laburnums grow well in a sunny position and on a well drained soil of chalk, sand, clay or loam but they do not tolerate being waterlogged as this will usually kill them. The Laburnum has adapted extremely well to the British climate and flourishes very well in most conditions.
To propagate the Laburnum tree, the method used is grafting although they can also be grown from seed.
Pests of the Laburnum Tree
Young Laburnum trees can be damaged by snails and they can also be affected by leaf mining flies, leaf mining months and aphids.
Pruning of a Laburnum Tree
Laburnum trees should be pruned in late summer but they can be pruned up until Christmas. They should not be pruned in the spring or early summer as they may bleed.
If you are growing your Laburnum as a specimen tree, remove any damaged stems and prune only to maintain the shape of the canopy.
If you are training your Laburnum tree over an arch for example, then regular pruning will be necessary in order to maintain it shape.
On grafted trees, any shoots which grow just below the graft should be carefully removed.
Other Uses of the Laburnum Tree
The wood was once greatly prized for cabinet making and for use as an inlay due to its hardiness and colour contrast. The heartwood is a chocolate brown, whilst the sapwood is a buttery yellow in colour, known as oyster work in the furniture trade.
At one time the Laburnum wood was also popular for making the chanters on Scottish bagpipes and it is also a very good wood for turning work.
Interesting Facts about the Laburnum Tree
The leaves of the tree were once used medicinally for the treatment of liver disorders, migraine and irritability. The leaves were also used at one time as an antidote to arsenic poisoning.
Article Source: http://www.graftingardeners.co.uk/laburnum-tree/