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.
- To 3035 feet tall, 2025 feet wide.
- Flower clusters are 1015 inches long.
- Pendulum has weeping branches.
- Bushy, spreading plant grows to 2030 feet tall and 1520 feet wide.
- Flower clusters 610 inches long.
- Pendulum is a weeping form.
- Hybrid between species above.
- To 15 30 feet tall, 1020 feet wide, with flower clusters 1020 inches long.
- Sunspire ('Columnaris') grows to 20 feet tall and 10 feet wide.
- Vossii, with 20 inches blossom clusters, is the showiest, most widely grown selection.