Robinia pseudoacacia--Black Locust
Hardiness Zones: 4 to 8
Height: 40 ft
Spread: 25 ft
Type: deciduous tree
Annual Growth Rate: more than 18 inches
Comments: Black Locust is hard wooded, grows best in a sunny location and tolerates any soil that isn't swampy. This hardy tree is a legume and has a suckering root system that forms thickets if not controlled. The fragrant, white flowers appear after the leaves and are borne in drooping clusters. The aroma can be
sensed from quite a distance. The fruit is a brown pod and the bark is coarse and fissured.
The medium-green, lacy leaves sometimes hide the spines, which are in
pairs along the branches. The cultivars can be difficult to locate.
'Aurea' - The new leaves are yellow but become increasingly green with age.
'Bessoniana' - A thornless cultivar with a compact oval form that will be 30 feet tall and 20 feet wide.
'Frisia' - The tree has bright yellow summer foliage color.
'Inermis' - A rounded tree with thornless branches.
'Lacy Lady' (Twisty Baby(R))(PAF) - This 8-foot tall plant has crooked stems and curled foliage.
'Purple Robe' - The new growth is purplish and the flowers are dark purple.
'Pyramidalis' - This cultivar is tall, narrow, and spineless. The plant will be 40 feet tall but only 15 feet wide.
'Tortuosa' - The branches are twisted, usually grated on a standard.
'Umbraculifera' (Globe Locust) - A dense, globe shaped head on a tree only 12 feet tall and wide, rarely flowers.
Check out more trees from the
Tree of the Week Archive.