Purging Buckthorn
Rhamnus cathartica
Alder Buckthorn
Frangula alnus
An uncommon shrub, which grows at lakesides often on limestone soil around Upper Lough Erne and the Shannon, Lough Neagh and Lough Beg. It is not tolerant of heavy shade under trees or very dry sites. There is some resemblance to dogwood (it is sometimes called ‘black dogwood’), but the oval leaves have an unusual pattern of almost parallel veins.
The inconspicuous white-green flowers (not unlike spindle flowers) are borne close to the dark branches and are followed by clusters of black berries on the female bushes only. This buckthorn is single sex, with about seven female bushes to each male.
Collection/Sowing
Pick the berries as soon as they are ripe in October, extract the seed, and stratify immediately. Some bushes crop in much more heavily than others. In order to ensure your own crop of berries, you need both sexes present: because of the odd ratio, you need to plant a dozen or so bushes.