Family: Fabaceae
Species: Robinia pseudoacacia L.
Common name: Robinia, Acacia, Acacia falsa - English: Black locust- Deutsch: Robinie, Scheinakazie, Silberregen
Etymology
Linnaeus dedicated the genus to the French botanist Jean Robin (1550–1629), a gardener at the French royal court who introduced R. pseudoacacia to Europe. The generic name derives from the Greek pseudo, meaning “deceitful” or “false,” and from the genus Acacia (false acacia) because the species had been confused with the mimosa plant.
Description
This deciduous, thorny North American tree rapidly colonises available soil through numerous spreading root shoots. It has erect trunks, often forked, with smooth branches and a branched crown. The wood is yellowish, while the bark is grey-brown and wrinkled, developing longitudinal fissures with age.
The compound leaves are alternate and imparipinnate, with 6–7 pairs of leaflets on short petioles. The leaflets are oval with an entire margin, pale green, glabrous, and bear small mucrones at the apex.
The intensely scented flowers are gathered in dense, pendulous racemes. Each flower, typical of legumes, has a papilionaceous corolla that is usually white or, more rarely, pink.
The fruits are smooth, leathery legumes that are red-brown when ripe and remain on the plant throughout winter. They contain 3–10 kidney-shaped seeds that are very hard and brown.
Habitat
Native to North America.
Properties and Uses
Robinia pseudoacacia significantly improves poor and degraded soils by fixing atmospheric nitrogen through a symbiotic relationship with bacteria of the genus Rhizobium. Its solid root system also helps consolidate landslide-prone soils.
The many uses of its hard, elastic, and moisture-resistant wood aid its rapid spread. It is also regarded as an excellent melliferous plant, as its abundant nectar produces a clear, delicate honey with a vanilla flavour and a fruity aroma reminiscent of its flowers.
When not fully bloomed, the flowers are used to prepare excellent omelettes or sweet fritters in batter. When added to salad, they impart a very pleasant taste. Once dried, the flowers are used to make herbal teas with calming properties.
Notes and Curiosities
In 1601, Jean Robin, the botanist and curator of the King of France’s Botanical Garden, imported Robinia pseudoacacia to Europe as an ornamental. That same year, Jean Robin planted an acacia in Paris, which still survives today, blooming each spring for over 400 years. The species has been cultivated in the Botanical Garden of Padua since 1662 and subsequently spread to the sub-Mediterranean area, becoming increasingly important for forestry. It is now naturalised throughout Italy.
It is highly heliophilous, as it does not regenerate quickly under the cover of other trees. In the Heller Botanical Garden, it is seen rising towards the sun with an open, expansive crown supported by twisted, scenic branches.