Robinia pseudoacacia is a deciduous tree, native to North America, which reaches 25-30 m in height. These trees are widespread in European and Australian forests, as in the past centuries they were used to consolidate landslides or uncultivated land. It has an erect stem, with dark brown bark, deeply fissured; the foliage is densely branched, roundish, tends to become disordered as the years go by; the young branches often have dark spines. The leaves are composed, light green, consisting of 7-21 small oval leaves, which become golden before falling, in autumn. In May-June it produces numerous pendulous inflorescences, made up of white or slightly golden, fragrant flowers that attract bees. In September on the plant you can see the pods that contain the large dark seeds. In many forests of our peninsula the locust trees have developed at the expense of native species.
To get the best development of the Robinia plant pseudoacacia it is advisable to place in a bright area, preferably sunny. In general these acacia trees are very vigorous, they can develop without problems even in unfavorable places, shaded or swept by strong winds. The black locust plants bear salt and pollution very well, so they are sometimes used as street trees. The robinias do not fear the cold and generally do not need watering, being satisfied with the water resulting from the rains. The trees of this type of acacia can show signs of suffering in the presence of strong winds, especially due to the fact that their wood is rather soft and not very resistant and undergoes the action of strong wind or heavy snowfall.
The trees of Robinia pseudoacacia they need loose, well-drained and very deep soils, but they develop without problems in any soil, provided they have enough space to develop a strong and deep root system. Trees of this type of acacia prefer fresh and deep soils, where they grow with great ease.
They are trees that are well suited to different situations and exposures, being rustic and resistant.
To maintain the plant in the shape of a bush, it is advisable to proceed with a pruning that cuts at the base to which to resort every 2 or 3 years.
For the multiplication of this type of tree, in spring, it is possible to sow the seeds of the previous year, after having left them in the refrigerator for at least 10 days; the plant produces numerous suckers, which can be rooted in a soil made up of peat and sand in equal parts. It is good to leave the new acacia shoots rooted for a while so that they take on the necessary strength for repotting.
When planting a black locust it is good to be careful not to ruin the earthen bread that covers the roots, so as not to compromise the rooting.
Robinia, Acacia - Robinia pseudoacacia: Pests and diseases
Generally these acacia plants are rustic and resistant and do not suffer from the attack of pests and diseases, although sometimes the larvae can spoil many leaves. They can also be attacked by scale insects. In the presence of parasites, intervene with broad-spectrum insecticide products to permanently eliminate the problem.