False Acacia or Black Locust Robinia pseudoacacia L.


The false acacia is a native of North America, where it grows in mixed broad-leaved woods from Pennsylvania to Georgia and Oklahoma. It was named after the French botanist Jean Robin, who introduced it into Europe in 1601. Today, it is widespread throughout western, central, eastern and southern Europe and in some areas is so familiar as to be mistakenly considered a native species. It reaches a height of 20 to 30 metres, the bark is deeply furrowed and the twigs thorny. The ornamental, odd-pinnate leaves appear at the end of May, and, soon after, the white, fragrant flowers, borne in pendent racemes. The false acacia has a wide-spreading root system extend-ing far from the trunk, and nitrogen-fixing bacteria in nodules on the roots; thus it improves the soil, though at the same time it poisons it with its root excretions. The false acacia is marked by the vigorous production of stump suckers, and regeneration by root suckers. It is a fast-growing tree and requires abundant light, but otherwise will grow on poorer and drier soils. For this reason, and because of its wide-spreading root system, it is often used for erosion control on slopes, embankments and sand dunes. In warm, wine-growing regions, it is also grown in forest stands. The flowers yield a rich harvest for bees, and the wood is of good quality.

Leaves: Odd-pinnate, 10—25 cm long, composed of 3—9 pairs of elliptic leaflets with rounded tips and entire margins. Flowers: Pea-shaped, white, borne in pendent racemes. Fruit: Flat, brownish pod or legume, 5—11 cm long, with blackish seeds.