Aeonium

Aeonium is a genus of evergreen succulents whose species range from compact rosettes to branching, shrub-like plants. Fleshy leaves form rosettes at the ends of stems, and mature plants may produce clusters of small, star-shaped flowers; size, color, bloom timing, and cold tolerance vary widely by species and cultivar. [RHS describes the genus](https://www.rhs.org.uk/plants/497/aeonium/details) as evergreen and often shrubby. ## Garden Use and Appearance Tree houseleeks bring bold leaf shapes and sculptural outlines to sunny, dry-climate gardens, rockeries, and containers. Some species stay low and form broad rosettes, while others develop tall branching stems. Choose a named species or cultivar when a planting needs a predictable mature size or color. ## Growing Conditions Most aeoniums perform best in bright light and sharply drained soil. The [RHS trial guidance](https://www.rhs.org.uk/plants/trials-awards/plant-trial-results/aeonium) notes that many become semi-dormant in very hot summers, when overwatering is a risk; some retain foliage better in light shade during heat. Tenderness also varies: protect plants from frost, and bring outdoor pots under cover before freezing weather where needed. Because species differ substantially, confirm the mature size and cold tolerance of the selected species or cultivar. ## Maintenance Water according to the species and season, allowing the growing medium to drain and dry between waterings where appropriate. Reduce watering during hot-weather dormancy and remove dead lower leaves as they dry; avoid applying one care schedule to the entire genus. ## San Luis Obispo County — January 2014 The [County-Approved Plant List](https://www.slocounty.ca.gov/departments/planning-building/forms-documents/environmental-forms-and-documents/plants-information/county-approved-plant-list) rates Aeonium varieties at F2: its most fire-retardant planting category, for 30–70 feet from a structure. This is the source’s group-level listing, not independent testing of every species or named cultivar. Follow the county’s conditions for plant health, watering and fire-buffer design: avoid overcrowding, remove dead material, maintain separate planting groups and prevent ground-to-canopy fuel connections. Keep other regional source ratings and their placement instructions separate; the county categories are not a universal flammability scale.