Rhamnus cathartica gets the “thorn” in its common name of Purging Buckthorn from its spiny stems which make it a useful addition to farm hedging for providing protected nesting sites. Compared with Alder Buckthorn (Rhamnus frangula), Purging Buckthorn prefers drier soil. The leaves of Purging Buckthorn are opposite rather than alternate.
Alder buckthorn has the word “thorn” in its name but actually is not thorny at all. It prefers wetter soils, even riverbanks and bogs so tends to be used by landscapers more than farmers.
We grow both of these species from seed on our farm in Herefordshire. If you would like help to choose which is best for your requirements, please do call us on 01989 552028.