Purging B. - An uncommon shrub, which grows at lakesides often on limestone soil around the shores of 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.
Alder B. - Alder buckthorn was once common, coppiced and the wood used for charcoal. It is a bush of wet, though not waterlogged sites and is found around the shores of Lough Ree. It has a very long flowering season and long fruiting season from July to November.