Credit: David Foley
Aeonium arboreum
Background and story
The Tree Aeonium (Aeonium arboreum) is a branching succulent subshrub native to the Canary Islands, where it grows on rocky slopes and volcanic soils in subtropical climates.
Known for its distinctive woody stems topped with rosettes of fleshy, glossy leaves, it forms a small, tree-like structure, often reaching up to about 2 metres in height.
The rosettes can vary in colour from green to deep purple depending on cultivar and exposure, and mature plants produce large conical clusters of bright yellow flowers, typically in late winter or spring. Its architectural form and ease of propagation have made it one of the most widely cultivated aeoniums worldwide.
Did you know?
It is native to a small group of Atlantic islands but now grows worldwide. The species originates in the Canary Islands and parts of Morocco, yet has become widely naturalised and cultivated across the Mediterranean and beyond.
Hardiness and conservation
The recorded RHS hardiness rating is H1C, which means this plant may be grown outside in summer, but still needs frost-free winter protection. Local hardiness always depends on local shelter, drainage, winter wet, salt-laden wind and the plant’s age and establishment.
Additional notes for Ireland and Britain
In Ireland and Britain, Aeonium arboreum is marginally hardy and best suited to mild, sheltered conditions, particularly in coastal or urban gardens. It prefers free-draining soil, full sun or light shade, and protection from winter wet, which can be more damaging than cold alone. It is often grown in containers or gravel planting, where drainage can be controlled, and may be moved under cover during winter in colder areas. The RHS classifies it as H1C, meaning it can be grown outside in summer but cannot tolerate frost and survives outdoors mainly in mild regions. In favourable Irish microclimates, it can form an attractive multi-stemmed shrub, though it is often treated as a seasonal or protected plant.
From a conservation and hardiness perspective, Aeonium arboreum is not considered threatened, being endemic but widespread within the Canary Islands and widely naturalised and cultivated elsewhere. Its success globally has reduced any pressure on wild populations. In terms of hardiness, it tolerates only light frost (generally around −2°C to −5°C) and is particularly vulnerable to prolonged cold combined with wet conditions, which can lead to rot. In an Irish context, it is best regarded as a versatile but climate-sensitive succulent, capable of thriving outdoors in favourable coastal conditions but requiring protection in harsher settings.
Notable features
- It behaves differently from most succulents. Rather than growing in summer, it is a winter‑growing plant, becoming active in cool, moist conditions and going partially dormant in heat.
- Each rosette has a built‑in lifespan. Like most aeoniums, individual rosettes are monocarpic, meaning they flower once, produce seed, and then die back, although the plant continues through branching.
- It naturally forms a “succulent tree”. Unlike many rosette succulents, it develops woody stems up to about 2 metres tall, giving it a true tree‑like structure.
- Its leaf colour can change dramatically. Depending on light and cultivar, leaves can range from bright green to deep purple or almost black, with stronger colour developing in full sun.
Earlscliffe notes
At Earlscliffe, they have been successfully growing outdoors all year round. They are checked by a little frost and prefer south-facing sunny slopes.