Culture
Easily grown in average, dry to medium, well-drained soils in full sun to part shade. Tolerates poor, dry soils and adapts to a wide range of soils and growing conditions.
Noteworthy Characteristics
Robinia pseudoacacia, commonly called black locust, is medium sized, suckering, deciduous tree that typically grows to 30-50’ (less frequently to 80’) tall. Although originally native to the Allegheny Mountains, it has escaped gardens and naturalized over time to cover much of the United States and southern Canada plus parts of Europe, Asia and South America. At its best, it will grow as a broadly columnar single trunk tree with a narrow oblong crown. It also will grow in suckering thickets. It is noted for its attractive compound leaves and pendant racemes of pea-like flowers. Branches are usually armed with short paired spines (to 1.25” long). Pinnate dark blue-green leaves, with each leaf having up to 23 lance-shaped to ovate leaflets. Leaves turn uneventful yellow in fall. Fragrant wisteria-like white flowers in pendant racemes (to 8” long) bloom in late spring. Bees are attracted to the flowers. Flowers are followed by smooth, flat, purple-brown seed pods (to 4-5” long). This species is also commonly called common locust, yellow locust, white locust, green locust, pea flower locust and false acacia.
Genus name honors Jean Robin (1550-1629), of Paris, gardener to Henri IV and Louis XIII of France, who received new plants from Canada.
Specific epithet means false acacia.
TWISTY BABY is a deciduous, multi-stemmed shrub or small tree which is perhaps most noted for its shrubby growth habit, zigzag branching (more pronounced on new growth) and curling of some of the mature leaflets. It can be expected to grow to 8-10' tall with a spread of 12-15' over 30 years. It is sold by nurseries in several different forms: (1) a multi-stemmed shrub, (2) a single trunk tree or (3) a top-grafted tree to a 6' standard. Trees feature a loose crown and fail to develop a strong central leader. Features pinnately compound, dark green leaves (leaflets to 7/8" long) which turn yellow in fall. This cultivar rarely produces the racemes of fragrant white flowers in May or resulting seed pods that are typical of the species. Miniature spines occur on some branches, but are smaller and fewer than on the species. This plant was patented in 1996 under the cultivar name of 'Lace Lady' (PP9,771), but is currently being sold by nurseries under the trademarked name of TWISTY BABY.
Problems
Borers can be a significant problem in some areas. Also susceptible to scale, leaf miner, leaf spot, powdery mildew and canker. Branches are susceptible to winter injury from heavy snows or ice.
Uses
Both tree and shrub forms make excellent specimens and conversation pieces for small, prominent areas in the landscape. Shrub form is effective in shrub borders, foundations, woodland gardens or as a screen. Also may be grown as a container plant.