Aeonium arboreum 'Zwartkop' (Large Purple Aeonium) - A striking succulent which forms clumps of 3-4-foot-tall gray-brown stems that often branch near their base but seldom above. The long, bare stems hold large terminal rosettes of very dark purple (seemingly black) leaves. Yellow star-shaped flowers that contrast well against the dark foliage form in long conical clusters from the center of the rosettes of mature older plants in summer, after which the stems bearing the flower die to the ground.
Plant in a well-drained soil in full sun near the coast to partial shade inland. Water deeply but infrequently - this is a winter growing species that is semi-dormant in summer and early fall when foliage is at its darkest. Protect from frost as stems will freeze at around 28° F. This plant is great along the ocean and tolerates drought and is reportedly resistant to deer predation.
Aeonium arborescens is native to Gran Carnaria Island in the Canary Islands. We have long grown this Aeonium arborescens cultivar as 'Zwartkop' as this was the name we received it by. It is also the name used in the Abbey Gardens catalogs in the early 1980's. In 1993 it was also under the name 'Zwartkop' that it received the Royal Horticultural Society's Award of Garden Merit in 1993. For more information about the species and a listing of other selections and hybrids of it, see our listing of Aeonium arboreum.
There has long been some disagreement on the cultivar name for this plant, mostly due to whether to use the Dutch name 'Zwartkop', meaning "black head" or the German name 'Schwartzkopf' (or alternatively 'Schwarzkopf') with the same meaning. Most conclude that this plant originated in Holland and was originally named there, making 'Zwartkop' correct and this is the story that is portrayed in "Dry Climate Gardening with Succulents" edited by Huntington Botanic Garden Director James Folsom. In an article on the Ruth Bancroft Garden website describing this plant, Dr. Dean Kelch, past Garden Director at the Ruth Bancroft Garden (and noted Aeonium expert) uses the name 'Schwartzkopf' and relates that this plant was a seedling raised in Europe (not indicating Germany or Holland) and that the University of California Berkeley Botanic Garden was the first institution to obtain plants in the US. Dr. Kelch also notes that many dark forms of Aeonium arboreum in the nursery trade are mislabeled as 'Schwartzkopf' (or 'Zwartkop'). We continue to list this plant with the more widely accepted spelling for its cultivar name.
Further confusion surrounds the parentage of this plant; this plant is sometimes described as a cultivar of Aeonium manriqueorum, but this name has been included in with Aeonium arboreum in Dr. Reto Nyffeler's treatment of the genus as published in "Illustrated Handbook of Succulent Plants: Crassulaceae" edited by Urs Eggli, Springer, 2003.
The information about Aeonium arboreum 'Zwartkop' displayed on this page is based on research conducted in our nursery library and from online sources we consider reliable. We will also relate those observations made of this plant as it grows in our nursery gardens and in other gardens that we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments we receive from others and welcome hearing from anyone who has additional information, particularly when they share cultural information that would aid others in growing it.