Robinia pseudoacacia - Black Locust

Robinia pseudoacacia or Black Locust is an interesting tree. From May to July, it produces pretty pendulous clusters of orange-scented flowers. Its delicate and light foliage, as well as its wide and airy habit, make it an ideal ornamental tree to create light shade that allows shrubs and perennials to grow at its base. The white flowers are typical of papilionaceous plants and measure 2 cm (0.8 in), while the clusters measure from 10 cm to 20 cm (3.9 in to 7.9 in) in length. The flowers are edible and can be enjoyed in fritters. They are also highly sought after by bees, resulting in delicious honey. This black locust owes its success to its fast growth and ease of cultivation in any soil and in almost all climates, except in windy regions because its wood is brittle.

Robinia pseudoacacia is a very hardy tree, native to the Eastern United States, from the Fabaceae family. These plants are capable of assimilating atmospheric nitrogen at their roots and therefore do not need to draw it from the soil, which allows them to grow in poor environments. Thanks to this characteristic, as well as its resistance to cold and drought, it has been mainly used to stabilise and enrich degraded soils. It is a long-lived tree with a columnar habit in its early years, and its sparse canopy becomes rounded over time. With rapid growth, it will reach an average height of 15 m (49 ft) with a spread of 8 m (26 ft). The bark, initially smooth, takes on an interesting fissured texture with age. The branches are strong but brittle, with a few thorns especially in their youth. Its deciduous leaves, measuring from 15 cm to 20 cm (5.9 in to 7.9 in), are divided into about twenty leaflets. They are highly decorative, starting with a bright acidic green when budding, then turning to a medium green before colouring golden yellow in autumn. Flowering takes place in May, on individuals about ten years old. The abundant pendulous inflorescences, 10 cm to 20 cm (3.9 in to 7.9 in) long, consist of white papilionaceous flowers that blend perfectly with the yellow foliage. This highly fragrant orange-scented flowering attracts pollinating insects and can be used for cooking fritters. It is followed by the formation of flat, reddish pods measuring 5 cm to 10 cm (2 in to 3.9 in) in length, containing 4-5 brown bean-shaped seeds. Being a sucker-forming plant, the black locust produces numerous suckers at its base, which should be removed in autumn to prevent it from invading local ecosystems.

Please note, only the flowers are edible; the rest of the plant is highly toxic. 

Robinia pseudoacacia is suitable for both small and large gardens, but it is not recommended in excessively windy situations. When planted individually in a small garden, it also thrives on slopes or in free hedges in a large garden. It is commonly used as an ornamental tree along avenues. You can place it against a background of evergreen shrubs or conifers (cypresses, thuja, yew, junipers). It can also be combined, in a flowering grove with poor soil, with other undemanding and highly ornamental trees or shrubs such as Sophora davidii, brooms, Indigofera gerardiana, a red oak (Quercus robur 'Purpurascens') or a purple hazel. Regularly pruned, it can form dense defensive hedgerows, which attract pollinators to the garden.

Its wood is of excellent quality, being very hard, virtually rot-resistant, and very durable.