Description
Rhamnus – Frangula – Buckthorn –
There are about 125 species of prickly, deciduous or evergreen shrubs or small tress, in the Buckthorn family, in this genus. They are widely distributed in Northern temperate regions, with a few in the Southern Hemisphere. They occur in woodland, heath land, scrub, bogs, or rocky places, often on alkaline soils. They are grown primarily for their leaves, which has good autumn color in some of the deciduous species, and their decorative fruits. The leaves are simple often with serrated edges and are held opposite or alternate. Tiny hermaphrodite or unisexual, cup shaped flowers, up to 1/8″ across, with 4 or 5 petals, are borne in axillary racemes or umbel like clusters, they are often fragrant and usually yellowish white, greenish white, or white. Some flowers, particularly those of R. frangula, are very attractive to bees. The fruits are fleshy, pea sized berries popular with birds. Grow in a shrub border, R. cathartica and R. frangula may be used as hedging. All parts may cause severe discomfort if ingested.
Grow in moderately fertile soil in full sun or partial shade. R. cathartica, R. frangula, and R. imeretina prefer moist soils. R. alaternus needs well drained soil in full sun. They tolerate salt laden air and alkaline soil.
Prone to scale insects, caterpillars, rust, Cercospora leaf spots, and Septoria leaf spots.
R. alaternus ‘Argenteovariegata’ – R. alaternus ‘Variegata’ – Italian Buckthorn – Alaternus – This rapid growers forms an erect to spreading, multi stemmed, evergreen shrub, grows 15′ feet tall and 12′ feet wide. From thorny branches it carries ovate to oblong, leathery, glossy, gray-green marbled leaves with prominent white edges, to 3″ long. In late spring and early summer it bears tiny, unsexual and hermaphrodite, greenish-yellow flowers, held in axillary clusters. Flowers are followed by spherical green fruit, 1/4″ across, ripening red then to black in late summer. Tolerates dry conditions, and polluted environments. Can become invasive.
Zones 8-9
