Robinia pseudoacacia

The leaf stipules of black locust turn into strong spines that persist for several years.

Info Flora gives the flowering period of black locust in Switzerland as May to June.

According to the Bavarian forestry institute LWF, black locust flowers produce large amounts of nectar, on average 1.7 to 2.9 mg in 24 hours (the text does not state the unit of measurement, such as per flower).

A Berlin study cited by LWF used net catches to record 20 wild bee species collecting at black locust, including several bumblebees.

Honey from black locust may also be sold under the name acacia honey (Akazienhonig), according to LWF.

Pure black locust honey is clear and liquid and crystallises very late because of its low glucose content.

In Germany black locust was assessed as invasive and placed on the BfN management list of widespread species with clearly documented harm to biodiversity.

It fixes atmospheric nitrogen, enriches nutrient poor soils and displaces threatened species of dry and lean grasslands.

Info Flora lists black locust as an invasive alien species in Switzerland, with a duty to inform under the Release Ordinance.

The Austrian Environment Agency (Umweltbundesamt) lists black locust among the 17 alien plant species considered invasive in Austria because they threaten conservation.

It spreads by thorny root suckers that emerge at a distance from the trunk.

Black locust, native to North America, reached Europe in the first third of the 17th century.