The approximately 35 species of Aeonium are members of the Crassulaceae family which includes many other popular and commonly grown succulents. These subtropical plants are native mainly to the Canary Islands off the coast of Spain, with a few species occurring in Madeira, Morocco, and parts of East Africa, like the Semien Mountains of Ethiopia; and Yemen. The plants were spread around the world by sailing ships which stopped for provisions in the Canary Islands, and the houseleek was known in Europe since at least 1711. Houseleeks have been grown in gardens for hundreds of years; and the name “Aeonium” comes from the ancient Greek “aionos” meaning immortal.
Aeoniums were originally lumped with Sempervivums but were separated to their own genus in 1836. Although they share similar growth and floral characteristics, and both plants are monocarpic, meaning they will die after flowering; unlike the sempervivums, aeoniums are not winter hardy and don’t tolerate frost and low temperatures. The death of the flowering rosettes is not fatal to your collection, however, because non-flowering offsets on the plant will not die off and new plants can easily be propagated from a rosette.
Houseleeks vary in size from small specimens which grow almost flat against the ground to woody shrubs with stout basal stems which can reach 1.5m tall or more, supporting multiple waxy rosettes on a basal stem. Their gorgeous spoon shaped leaves can be glossy or matte and come in shades of burgundy and green, sometimes variegated with splashes of palest gold. The spring or summer flowers are star-shaped and typically yellow, but can sometimes be creamy-white or pink. These are borne on mature plants in pyramid shaped clusters at the end of the stems. Some have breath-taking inflorescences and others are not very impressive. Extensive hybridization has expanded their range considerably and today aeoniums are without a doubt, some of the most beautiful and sought after additions to succulent collections.
Here are a few of our favourites – just too wet your appetite!
Aeonium arboreum (Tree Houseleek, Irish Rose) is an upright plant with bright, glossy green leaves in rosettes 20cm wide. It grows quite quickly and can eventually reach 1 to .5m tall with an equal spread, producing impressive panicles of small yellow flowers. The tree houseleek is valued for its architectural shape and is used as a contrast for other companion plants in the garden or in containers.
Aeonium arboreum ‘Atropurpureum’(Purple Tree Houseleek) is a truly beautiful species with tall arching stems and large heads of glossy, dark, reddish purple foliage. It can grow 1 to 1.5m tall with an equal spread, and produces impressive panicles of small yellow flowers. It can be planted in full sun to bright shade. The tree houseleek is valued for its architectural shape and is used as a contrast for other companion plants in the garden or in containers.
Aeonium arboreum 'Zwartkop’ (Black Tree Houseleek, Black Rose) is one of the oldest cultivars and still immensely popular because of its large heads of deep purple-black foliage. It grows about 1 to 1.5m tall with an equal spread, and prefers very bright light to full sun. In more shady situations the leaf colour is not as brilliant. Mature plants will produce impressive panicles of small yellow flowers, which, set against the almost black foliage, are most impressive. Use its height and wonderful foliage as backdrop plant to show off other companion plants to maximum advantage.
Aeonium arboreum albovariegatum is a bushy succulent, up to 60 cm tall with beautiful rosettes up to 30 cm in diameter, with white margined leaves, often tinged with pink. Use this beautiful houseleek to full advantage in containers, planted singly or in combination with other succulents or water-wise perennials and annuals. It needs protection from harsh sunlight.
Aeonium haworthia (Pinwheel Aeonium) produces attractive rosettes of bluish-green leaves with rosy-red margins. This compact houseleek grows about 30 to 40cm tall, with an equal spread, and is one of the more attractive bush-forming species. The flowers are very pale yellow to nearly white and sometimes tinged pink. This plant received the Royal Horticultural Society's Award of Garden Merit in 1993 and has many attractive hybrids. It is also worthwhile growing in colder climates because it is hardier, tolerating temperatures as low as -3°C, but is still tender to frost. In these regions it can be planted in dish gardens and other containers which can be brought indoors, or placed under a covered patio in winter. In coastal regions it can be planted in sun to light shade, but in hot inland locations it requires semi-shade to bright, full shade. It likes a well-drained soil and tolerates little to no summer irrigation. The pinwheel aeonium grows well in beachside gardens, is excellent planted on steep or rocky slopes. It is also a good understory plant for large trees with extensive roots, like Eucalyptus.
Aeonium haworthia ‘Kiwi' is a hybrid with the same growth requirements as A. haworthia, but is more tender to low temperatures than A. haworthia. It produces rosettes in soft shades of pale banana, strawberry and lime, making it a mouth-watering tropical treat. To keep its brilliant colours, plant it where it receives bright light and some sun, but shade it during the hottest time of the day, or the leaves will become sunburnt. Because it only grows about 25 to 50cm tall with an equal spread, this plant makes a very attractive and showy pot plant, both indoors or outdoors.
Aeonium decorum (Green Pinwheel) is a beautiful branching plant, forming a mound about 30 to 60cm tall with an almost equal spread. It prefers bright shade to sun and produces rosettes of pale green leaves with orange-red tones and red leaf margins. The flowers are a soft pink.
Aeonium decorum 'Sunburst' produces large rosettes of variegated green and creamy-white leaves, held on long bare stems; and pale yellow flowers. It will grow in semi-shade to sun to about 50 or 60cm tall with an equal spread, and requires only occasional watering once established. This houseleek makes a great contrast plant in the garden or in pots.
Aeonium tabuliforme (Dinner Plate Aeonium) is an unusual houseleek which grows in vertical cracks in the lava flows on the rather steep slopes of the coastal cliffs on Tenerife in the Canary Islands as well as several other places in the archipelago. Individual plants form a stemless, flat disc of overlapping lime green leaves with a velvety texture and can grow to 45 cm in diameter. Sometimes, the form will be crested in the centre, making it look like a big green turtle! The yellow flowers are produced on tall panicles. The dinner plate aeonium prefers semi-shade and does not tolerate frost. Because this Aeonium produces few pups and propagation is most often through seed, it can be difficult to find.
Aeonium canariense (Giant Velvet Rose) has bright green rosettes up to 20cm in diameter and the leaves can be seasonally tinged with red. This houseleek is one of the few with hairs all over its thick leaves. It grows about 30cm tall when not in bloom, but the blooming stems can reach up to 60cm tall.
Aeonium sedifolium (Dwarf Aeonium) is not easily recognisable as an aeonium with its branching stems of small green rosettes with red stripes, and growing only 20 to 30cm tall with an equal spread. It grows in sun or semi-shade and is a pretty filler plant for containers.
In the Garden:
Houseleeks are without a doubt, some of the most beautiful and sought after additions to succulent collections. And, because they come in various sizes, heights and colours, they are extremely versatile, and can be used in so many garden styles and settings. They are are often used in architectural city and courtyard gardens in coastal Mediterranean and sub-tropical climates. Houseleeks grow beautifully in pots, combining wonderfully with other succulents, and in cold regions the pots can be brought indoors to overwinter.Planted in mass, they have the most impact, and can even be used as a groundcover. The taller varieties can act as contrast or accent plants in the flower garden when combined with other water-wise perennials or annuals. Being drought tolerant plants they are used as part of xeriscaping – a landscaping method that reduces or eliminates the need for supplemental water from irrigation. Combined with other succulents they are also used to fire-scape gardens prone to wild fires.
Most houseleeks originate The Canary Islands, a Spanish archipelago located off the west coast of Africa, and known as “the islands of eternal spring” because of the mild temperatures year-round. The mild climate occurs largely because of their location in the path of the Canary current, a cool ocean current which flows toward the southwest. The islands lie blocking this current so they are directly affected by these cooler waters. Therefore, temperatures on the islands are usually a couple of degrees cooler than expected at their latitude. The archipelago generally experiences mild winters and warm summers. Year round the Islands receive warm, sunny weather with an average temperature that ranges from 17°C in the winter to 24°C in the summer. There are rarely major temperature extremes, though it is not uncommon for the mercury to rise above 30°C in the peak of summer, especially in the eastern areas.
The rainfall pattern in the Canary Islands is typically Mediterranean, with a maximum rainfall in winter and virtually no rain in the warmest months, so these plants are perfectly adapted to many similar climates around the globe. They are mostly winter growers and require moderate watering during their growing season and only an occasional light watering during summer. In their native climate, as the dry summer months begin, many will curl their leaves in and go into a form of dormancy. In cultivation, however, if given some shade and water, most will continue to grow, though perhaps less vigorously. Generally, most are moderately drought tolerant, with some being more tolerant of dry conditions than others, but bear in mind that the roots are shallow and hair-like, with all the water-storing parts of the plants being in the stem and leaves. These wimpy roots are prone to drying out and many of these plants will decline during prolonged dry spells if they are not watered. Plants in containers will require more frequent watering than those growing in the ground.
Some also tolerate cold better than others, but generally houseleeks are frost tender and will not withstand heavy frost or extreme temperatures, and if temperatures drop lower than -1° C the plants will need extra protection. Houseleeks need sun but most also like some shade; generally the green varieties prefer some shade while the purple ones prefer more sun. They are not fussy about soil and long as it is fertile and free draining, and this is especially important if you are growing them in pots. If your soil does not drain well, add river sand to the beds or potting soil. River sand is available from your local garden centre. In-ground plants rarely need feeding, but will benefit from a light spring mulch of compost, applied around the base of the plants. Specimens growing in pots will also benefit from some compost and an occasional feeding with a liquid fertiliser like seaweed or fish emulsion. Pruning is not required, but if you need to cut away some branches, this will not adversely affect your plant.
Almost all aeoniums are very easy to propagate from stem cuttings; leaf cuttings are less successful but the only way to propagate stemless rosettes such as A. tabuliforme. Allow the cut ends to dry out for a day or two before pushing them into fresh potting soil and watering. Keep the soil barely moist thereafter. Rooting powder may be used but is not essential. Terminal bud removal technique is used for producing variegated offsets. Seeds can also be sown in spring when the soil temperatures are warm and between 19 and 24°C, but germination can be slow.
Pests & Diseases:
Most pests won't bother your succulent plants; they can't get through the tough skin and waxy coating on some species, and other types just don't taste right. As a group, succulent plants don't seem susceptible to many bugs or diseases, but watch out for snails they love this plant!
The most common problems when caring for aeonium plants is root rot, caused by soils which do not drain well. To prevent root rot in containers, unglazed clay pots are best. Keep the roots moist but never soggy.
Mites, aphids, mealybugs and scale may become a problem, especially if the plants are grown in a protected area under a roof. Combat these with horticultural soaps or neem oil. Be careful when using soap spays, however, as spraying too frequently can cause discoloration and lesions on the skin of the plant. Often, a good spraying down with a strong jet of water will do the trick.