About the genus
Once considered to be giant houseleeks (Sempervivum), we now realise that these plants evolved from Sedum-like plants which still grow in north Africa. Aeonium, Monanthes and Aichryson are very closely related.
Aeonium are very popular as house plants and this has resulted in a lot of pretty cultivars and hybrids. Most species grow wild in the Canary Islands with each island having its own combination of species. Two species grow on Madeira and another on some of the Cape Verde Islands. There are also pockets of Aeonium native to east Africa and the Arabian Peninsula. This is called a disjunct distribution.
Some species produce rosettes (which can vary in size from a couple of centimetres to 30+cm across) at the tip of long stems. Others, like Aeonium cuneatum, remain stemless.
Generally, yellow flowers are produced on the ends of long inflorescences but pink flowers (e.g. A. goochiae), red (A. nobile) and white (A. haworthii) make a pleasant change.
How to grow them
Unlike many succulent plants in cultivation, Aeonium are winter-growers. It is normal for them to have very little water from May to August. Watering succulents in winter can be tricky and you should never allow plants to stand in water. During dull, cold periods, withholding irrigation for a couple of weeks will do no harm.
Plants are not particular about a compost preference but the growing medium needs to be well-drained.
I add a lot of gravel to the mix to make the pots heavier for the taller-growing species, so they do not topple so easily.
Only one species is frost-hardy (A. spathulatum) so it is prudent not to let temperatures fall much below 5°C. If you have some very cold nights, boost the daytime temperature the next day and plants will recover.
In the wild very few species grow in full sun apart from A. sedifolium and A. nobile. The rest grow mostly on north-facing cliffs in shade. Generally, they are not good greenhouse plants unless they have shade and plenty of air movement. Plants will come to no harm being put outdoors for the summer but a little protection from rain is preferable.
It is not necessary to feed Aeonium, as generally this causes them to bolt or to produce weak stems, and they gain all the nutrients necessary from a gritty compost. Some species retain dead leaves under each rosette and this is an ideal place to harbour pests, especially mealy bugs. These are best removed when the plants start to grow in autumn. Take care if using a proprietary spray as it often removes the bloom from leaves. A small paintbrush dipped in methylated spirits is a safer and easier way to target the bugs and their eggs.
Text and photos: Ray Stephenson except Aeonium ‘Zwartkop’ Photo: Elizabeth Maddock
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