Tree houseleek
Plant 362 in the 400 week countdown
There are 43 accepted species in the genus Aeonium. They are distributed from Macaronesia through North Africa to the Arabian Peninsula. Most species are found only on the Canary Islands, where they may be restricted to one or two islands, and are usually found growing on cliffs or rocky areas, in well-drained soil in full sun or partial shade. The minimum temperature to cultivate most Aeonium species is -3 degrees Celsius, if they are kept on the dry side. Consequently, most species are unsuitable for growing outside in the United Kingdom, except in mild areas where there is perfect drainage. As a result, tree houseleeks make good pot plants for a cool conservatory, where they require little watering given their succulent nature. However, taller varieties will need additional support, as they can become top heavy. Tree houseleeks are grown in the Arid House at Oxford Botanic Garden, alongside other succulents and cacti.
There are many striking tree houseleeks, some of which have varietal names. Aeonium arboreum‘Schwarzkop’ has deep purple, nearly black, leaves, against which the yellow flowers look very striking. Aeonium arboreum ‘Atropurpureum’ is similar, but with red-flushed leaves. Other species have been selected for their leaf variegation, such as Aeonium haworthii ‘Variegatum’, which has tri-coloured rosettes that start out lemon-yellow and become green with a red edge as they age. It is important to remember that good light is needed to maintain these colours. During winter, colours are often less striking but, as the days lengthen, colour intensity is restored.
Tree houseleeks are easy to propagate by tip cuttings. Other methods of propagation include leaf cuttings and seed. Pests are not usually too much of an issue, although mealy bug aphids and vine weevils can sometimes be a problem.
Lucinda Lachelin
Botanical horticulturist
Oxford Botanic Garden and Arboretum
Oxford Plants 400
Twitter: @Plants400
Further reading
Huxley, A (1999) The New Royal Horticultural Society dictionary of gardening. Groves Dictionaries Inc.
Phillips, R and Rix, M 1997. Conservatory and indoor plants. Pan Books.
