Native to central and southern Europe, these are among the garden's prettiest flowering trees. They grow upright and are typically pruned to a single trunk but can be shrubby if allowed to keep basal suckers and low branches. Olive-green bark is a trademark; bright green leaves are divided into three leaflets (like clover leaves). Beautiful in bloom in mid- to late spring, when hanging clusters of bright yellow, fragrant flowers appear. Flexible branches make them easy to espalier; they can be trained on narrow arches to form spectacular flowering tunnels. They're also good as single specimens, in foundation plantings, and in groupings.
Plants need good drainage; will tolerate alkaline soil. Suscep- tibility to insects and disease can make them rather short lived. They don't do well in extended summer heat, so protect them from hot afternoon sun. Prune after bloom. Removing seedpods promptly may increase the next year's bloom.
L. alpina. SCOTCH LABURNUM. To 3035 ft. tall, 2025 ft. wide. Flower clusters are 1015 in. long. 'Pendulum' has weeping branches.
L. anagyroides. COMMON GOLDENCHAIN. Bushy, spreading plant grows to 2030 ft. tall and 1520 ft. wide. Flower clusters 610 in. long. 'Pendulum' is a weeping form.
L. xwatereri. Hybrid between species above. To 15 30 ft. tall, 1020 ft. wide, with flower clusters 1020 in. long. 'Sunspire' ('Columnaris') grows to 20 ft. tall and 10 ft. wide. 'Vossii', with 20-in. blossom clusters, is the showiest, most widely grown selection.