The most common plants in cultivation tend to branch freely and make excellent beginner propagation subjects. Each rosette will flower after a few years with an elaborate burst of yellow, white, pink, or rarely red flowers, and then die, leaving any other branches to live on. Only one Aeonium (simsii) makes a lateral inflorescence which does not result in the death of the rosette. Aeonium flowers usually make a dramatic statement in the garden and often attract bees.
Most Aeonium species are actually rare in cultivation. Mass-produced cultivars include the purple-leafed “Zwartkop” and several of its named hybrids, plus a few delightful variegates, including “Kiwi” and “Sunburst”.
The fine marginal hairs which decorate most Aeonium leaves are a useful feature to distinguish them from other similar-looking rosette succulents from the New World, like Echeverias. Aeoniums typically have thinner leaves, with two exceptions: sedifolium and nobile, which also lack marginal hairs but may have tiny bumps instead. Most Aeonium species (except tabuliforme) grow a stem, which may reach up to 1m tall, and when they flower the distinctive cone or mound-like inflorescences give away the genus. Plants which are kept constrained and pot-bound will be smaller, branch less and take longer to flower.
Other features which can be used to identify Aeonium species include the surface texture of the stem (which may be flaky, smooth, fissured, or hairy) and the texture of the leaves (which may be smooth, sticky, or fuzzy). Some leaves may have water-storing idioblasts on the underside, others may have tannic stripes on top.
Consider your climate when deciding where to put your plant and what care to give it. Aeoniums for the most part come from mild locations and they are best suited to mild Mediterranean climates. They do not like freezing cold or extreme heat. Provide a warm, sunny location when overwintering them and consider sun protection during the hottest days of summer in marginal climates. The greatest danger in summer comes when it does not cool down at night. In areas with heavy summer rainfall, overhead protection may be necessary to prevent rot.
Aeoniums also suffer from the same insect pests that affect other succulents, including mealy bugs (which hide out at the base of leaves, close to the stem near the growth points) and aphids (found in a similar location or at the center of the rosette). The latter are particularly problematic during flowering. Look for ant traffic as a sign of infestation. Aeonium flowers tend to be bug magnets in the patio or container garden; this behavior is greatly reduced by natural predation in the landscape.
Aeoniums are delectable to most herbivores, including mammals (squirrels, rabbits, livestock), especially when newly planted and during times of drought, since the succulent leaves store water.
This is best done during a season of active growth, ideally in fall. The solitary plants which do not branch can be forced by cutting out the growth center, and all Aeoniums can be grown from seed. They are self-seeding under permissive conditions. The seed is quite fine and young seedlings require overhead protection until there is a recognizable rosette. Hybrid seed may be common. Most Aeoniums can also be grown from an intact leaf left to root in bright shade, though the difficulty varies with the plant and the young rosettes are sensitive early on.
They do most of their growing from fall through spring, slowing down or going dormant in summer depending on conditions. Aeonium rosettes have fewer leaves in summer, often much smaller than normal and closed up on themselves to conserve moisture. Some plants also develop red or purple highlights when they experience sun or drought stress. This is normal.
It is important to understand and respect this annual cycle, which may be exaggerated by summer heat and exposure, especially in marginal (hot) climates. Despite their appearance in summer, Aeoniums do not need extra water at this time. On the flip side, during the period of active growth, which coincides with the darkest days of the year, it is important to provide strong light. Indoor Aeoniums usually require hours of daily sun during this period.
They are also found in Cape Verde (gorgoneum), Madeira (glandulosum, glutinosum), coastal Morocco (korneliuslemsii), and East Africa (leucoblepharum, stuessyi). Within the Canary Islands, distribution varies by island (which have from 0 to 13 native species each) and by elevation/vegetation zone (simsii, smithii, and spathulatum grow up to 2000m or more and are the most frost-tolerant). Rainfall on any given island with altitude may vary over 10-fold depending on the location, and this is reflected in the plants’ behavior in cultivation. In areas with more rainfall, they occur on steeper and rockier slopes, where they can outcompete other plants. The tropical species are quite rare in cultivation and the East African plants are particularly variable. Aeoniums have naturalized throughout permissive climates around the world, including Oceania, as ocean trade spread these plants from a popular refueling station.
Rudolf Schulz, Aeonium in Habitat and Cultivation, 2007
