Small deciduous spring flowering trees, noted for their cascading trails of yellow flowers. A robust and hardy plant that stands up well to strong winds and bad weather.
Family: Fabaceae (legume, pea, or bean family)
Botanical Name: Laburnum
Common Names: Bean tree, golden chain tree, golden rain, golden showers.
Foliage: Deciduous, dark green, oval-shaped trifoliate leaves (small leaflets in groups of three).
Blossom: Pendulous racemes of bright yellow pea-like blooms. Usually followed by bean-like pods.
Flowering Period: May to June.
Soil: Well-drained soil (chalk, clay, sand or loam). Acid, alkaline or neutral pH.
Conditions: Full sun, any aspect, exposed or sheltered.
Habit: Branching/spreading habit that provides light dappled shade in spring and summer.
Type: Small tree.
Toxicity: All parts of this plant are highly toxic if eaten.
Hardiness: Fully hardy in the UK.
All parts of this plant are poisonous, including the seeds, so keep out of reach of children and pets. Wear protective gloves and clothing when handling.
The golden chains of yellow flowers look particularly good when silhouetted against a blue sky or against a green background. Once the flowers have finished the open foliage creates a nice dappled affect.
Laburnum trees usually achieve a good shape, reaching a mature height of around 26ft (8m) or more.
Plant bare-root specimens from autumn to spring. Plant container-grown plants at any reasonable time of the year. Thrives best in full sun but it will take a little light shade.
Plant in any good well-drained garden soil in full sun. Incorporate plenty of well-rotted manure or garden compost into the planting hole.
Young saplings can either be staked to form an upright tree or trained to grow over an arch, where the flowers will appear to pour down through it like rain.
Stake young trees. Water in dry weather until well established.
Pruning is not normally necessary, except for the removal of any dead, damaged or crossing branches, once flowering has finished. Pruning should only be carried out between late summer and mid-winter as the sap may 'bleed' heavily at other times.
Susceptible to attack by aphids and leaf-mining moths and leaf-cutter bees. The leaves can be affected by powdery mildews and silver leaf. The roots are susceptible to honey fungus.
Sow seed in the autumn in pots or trays of seed compost. Protect in a cold frame or cool greenhouse overwinter.
Note: cultivars don't usually come true from seed, so named forms should be increased by grafting.
Popular varieties of Laburnum trees available in the UK, include:
Laburnum anagyroides (common Laburnum) is a fast-growing, robust tree that flowers in late spring. The sweetly scented flowers are followed by silvery pods. Height to 26ft (8m). For sale at Thompson & Morgan. Cultivar 'Aureum' has young yellow leaves that turn green. The variety 'Yellow Rocket' provides profusion of yellow flowers on a tall, thin tree. For sale at Crocus.
Laburnum alpinum (Scotch Laburnum) similar to the common laburnum but has larger darker leaves and longer flower racemes. Flowers in early summer. Good cultivars include 'Pendulum' which is a compact form with pendulous, branches as well as the flowers, making a fine weeping tree. Available at Crocus.
Laburnum x watereri is a free-flowering tree with long racemes of yellow flowers in early summer. Good cultivars include: 'Sunspire' and 'Vossii', which both make fine specimen trees. For sale at Crocus. For sale at Gardening Express.