Black Locust Incredibly tough tree, tolerant of drought. Spiny shoots and pinnate leaves with small round leaflets turn a light yellow in Autumn. Rugged, deeply fissured bark. Often suckers, so best give it plenty of space. Fragrant, creamy-white pea-like flowers are produced in drooping clusters from late spring. Popular in cityscapes thanks to its resistance to pollution and poor air quality. An incredibly beautiful example can be met in person at Birr Castle, Co. Offaly, which may be Irelands oldest. Well drained soil vital. Site: Prefers shelterSoil: Must be well drained soilPosition: Full sunSeason of Interest: Spring flowers, Autumn fruitHardiness: Fully hardyHeight: 40ft (12m) Spread: 30ft (9m) after 40+ years