Identity & taxonomy
- Scientific name
- Aeonium arboreum (L.) Webb & Berthel.
- Family
- Crassulaceae
- Genus
- Aeonium
- Order
- Saxifragales
- IUCN status
- Least Concern (LC)
- Wikidata
- Q303620
- Sempervivum arboreum L.
- Aeonium manriqueorum Bolle
- Tree aeoniumen
- Tree houseleeken
- Irish roseen
- Black rose treeen
- Trädaeoniumsv
- Treaeoniumno
- Træaeoniumda
- Puuaeoniumfi
- Baum-Aeoniumde
Canary Islands (especially Tenerife, La Palma, Gran Canaria, La Gomera)
How to identify it
Growth habit. Evergreen subshrub with woody branching stems topped by flat rosettes of fleshy leaves. Each rosette sits at the tip of a single stem 5–30 cm tall; older plants branch and produce multi-stemmed bushy specimens. Stems are covered with fine ringed leaf scars from previous seasons. Mature plants flower from the rosette centre with a tall yellow flower spike — but flowering kills the rosette (monocarpic), so flowering specimens always look dramatic and slightly tragic.
Leaves. Spoon-shaped (spathulate) fleshy leaves 5–10 cm long arranged in a flat rosette 10–20 cm across. Surface is smooth and waxy; margins have very fine cilia (tiny hairs) visible only with a hand lens. Colour ranges from glossy mid-green in the species to deep purple-black in 'Schwarzkopf' to yellow-cream variegated in 'Sunburst'. Leaves curl tightly inward during summer dormancy — the rosette closes from a flat plate to a tight ball.
Flowers. Tall pyramidal flower spike 30–60 cm rising from the centre of a mature rosette in spring or early summer, carrying hundreds of small yellow star-shaped flowers. Flowering is monocarpic — the flowering rosette dies after the spike finishes, though side branches survive. Indoor flowering is uncommon; outdoor specimens in mild climates flower more reliably.
- Tree-like branching woody stem topped by flat rosettes — unique among popular succulents.
- Spoon-shaped fleshy waxy leaves in flat rosettes 10–20 cm across.
- Old leaf scars create fine ringed pattern on bare stem.
- Summer-dormant — leaves curl inward, opposite of typical succulent rhythm.
- 'Schwarzkopf' cultivar is among the darkest-coloured plants in cultivation.
Commonly confused with
Mexican snowball
Similar rosette form but Echeveria stays at ground level on a very short stem and never develops a tree-like branching habit. Echeveria leaves are thicker and more cupped; Aeonium leaves are flatter, more spoon-shaped. Echeveria is summer-active and winter-dormant — the OPPOSITE of Aeonium.
Common houseleek / hens-and-chicks
Closely related ground-hugging rosette without any tree-like stem. Sempervivum is hardy outdoors in cold climates; Aeonium dies at −2 °C. Sempervivum produces stoloniferous offsets ('chicks'); Aeonium branches at the stem instead.
Jade plant
Tree-like branching habit but with paired thick oval leaves arranged along the stem, not in terminal rosettes. Different growth pattern entirely once you compare the silhouettes.
Saucer plant
Sister Aeonium species with much larger flatter rosettes (30–60 cm wide vs 10–20 cm in arboreum) and typically a single unbranched stem. Often labelled as A. arboreum in trade.
Care
Light
Brightest possible — 4+ hours direct sun for darkest colour.
Aeonium arboreum is a sun-worshipper from open coastal cliffs and rocky scrub on the Canary Islands. Indoors, an unobstructed south or southwest window is needed for the dark cultivars to develop their full colour — anything dimmer and 'Schwarzkopf' fades from black to bronze to plain green. A summer outdoors on a sunny balcony dramatically improves colour saturation. Below 10,000 lux the plant survives but rosettes loosen, leaves elongate, and dark cultivars green up.
Seasonal: Nordic latitudes above 55°N: the dim October–March stretch fades dark cultivars to bronze-green; full colour returns by April–May with returning sun. Many growers move plants to balconies or sunny window-trays from May onwards specifically for colour development.
Water
Top half of pot dries — every 10–14 days; less in summer dormancy.
Aeonium arboreum has the OPPOSITE seasonal rhythm of most succulents — it grows in autumn, winter, and spring (October–April in the northern hemisphere) and goes dormant in summer. Water normally in the active growing season when the top half of the pot dries. In summer dormancy (June–September) reduce watering dramatically: a small amount once every 3–4 weeks just to prevent fully shrivelled roots, but no more. Watering an aeonium in summer the same as in winter rots the roots — the species' single most common kill mechanism.
Seasonal: Summer (June–September): cut watering to roughly a quarter of normal; plant is dormant. Autumn–spring (October–May): water more frequently than typical succulents — every 10–14 days when top half dries.
Soil
Free-draining cactus/succulent mix with extra grit.
Two parts commercial cactus mix or two parts peat-free houseplant mix with one part horticultural grit/coarse sand and one part perlite. The mix should drain water within seconds, not minutes. Aeonium grows wild on rocky cliff faces and resents heavy water-retentive compost. A slightly larger ratio of grit than typical for jade plant or echeveria.
Humidity
30–60 %; tolerates dry indoor air.
Tolerates ordinary indoor air without intervention. Native habitat on Canarian cliffs has highly variable humidity from sea-fog moist mornings to bone-dry afternoons. No misting, pebble tray, or humidifier needed.
Temperature
10–24 °C; prefers cool — frost-tender.
Cooler-tolerant than most popular succulents and actively grows BETTER in cool conditions. A 13–15 °C bedroom or unheated conservatory is ideal during the autumn-spring growing season. Sustained heat above 28 °C combined with bright sun triggers protective summer dormancy. The species is killed outright by hard frost (−2 °C and below) so cannot be left outdoors year-round in continental or Nordic climates.
Fertilizer
Quarter-strength balanced feed monthly during active growth.
Quarter-strength balanced NPK monthly during active growing season (October–April). Skip feeding entirely during summer dormancy (May–September). Aeonium is a light feeder; over-fertilising shows as overly soft leggy growth and reduced colour.
Pruning
Cut leggy stems back hard; cut tops re-root as new plants.
Cut leggy stems back to 10–15 cm above the soil at any time during active growth. The original cut stem re-shoots from below the cut within 4–6 weeks, often producing 2–3 new branches. The cut-off rosette can be re-rooted as a fresh new plant — see propagation. Aeonium tolerates very heavy pruning and rebounds reliably.
Repotting
Every 2–3 years in autumn (start of growing season).
Move up by one pot size in autumn as the growing season starts. Use shallow wide pots — Aeonium is shallow-rooting and a deep pot stays wet at the bottom and rots roots. Refresh top 2 cm of soil annually in non-repot years.
Stem-tip rosette cuttings
easy~3–6 weeksCut a stem with rosette intact, leaving 5–10 cm of stem below the rosette. Let the cut surface callus for 3–7 days in shade. Place the callused cut on the surface of dry succulent mix; do not bury. Mist soil lightly every 2–3 days. Roots emerge within 3–6 weeks. The most reliable propagation route — works every time.
Stem cuttings without rosette
easy~6–10 weeksCut a section of bare woody stem 10–15 cm long, callus for 1 week, and plant in dry succulent mix. New rosettes emerge from dormant buds along the stem within 6–10 weeks. Useful for rejuvenating very leggy specimens.
Leaf cuttings
difficult~Erratic; many leaves failUnlike echeveria and jade plant, Aeonium leaves do NOT propagate reliably from individual leaf cuttings. Some leaves form roots but few produce a new rosette. Stem-tip cuttings are dramatically more efficient — included here only because the question is asked.
Cultivars
'Schwarzkopf' / 'Zwartkop'
The famous near-black cultivar: leaves so dark purple they appear glossy black in full sun. The most-photographed and most-traded Aeonium worldwide. Selected in Dutch nurseries in the 1950s; the names mean 'black head' in German and Dutch respectively.
'Atropurpureum'
Dark purple-bronze rosettes — less intensely black than 'Schwarzkopf' but more saturated than the species. Greens up significantly in shade.
'Variegatum'
Cream-yellow variegated leaves with green centres; slower-growing than the species.
'Sunburst'
Technically a hybrid (A. davidbramwellii × A. arboreum) but often labelled as A. arboreum 'Sunburst'. Striking yellow-and-cream variegation with pink-flushed margins in sun.
Common problems
Rosette closing tightly into a ball
Symptom
From late spring through summer, leaves curl inward and the rosette closes from a flat plate to a tight green or bronze ball.
Cause
Normal summer dormancy. Aeonium is a winter-grower and goes dormant in summer — the curling protects inner leaves from heat and drought.
Fix
No action needed. Reduce watering dramatically; water perhaps once every 3–4 weeks just to prevent root death. The rosette opens again from October–November as cooler weather returns. Owners frequently mistake this for the plant dying and over-water in panic, which kills the roots.
Dark cultivar fading to green
Symptom
'Schwarzkopf' or 'Atropurpureum' loses its near-black colour and becomes bronze or plain green.
Cause
Light too low. Dark cultivar colour depends on bright direct sun to suppress chlorophyll and preserve anthocyanin pigment.
Fix
Move to the brightest available window with several hours of direct sun. Colour returns over 3–6 weeks of bright exposure. A summer outdoors on a sunny balcony is the most effective way to develop and maintain dark colour.
Stem becoming leggy with rosette only at the very tip
Symptom
Long bare stem with a single rosette at the top and ringed scars below where leaves used to be.
Cause
Normal Aeonium growth pattern combined with old leaf shedding — the plant naturally forms a tree-like silhouette.
Fix
Cosmetic only. If the bare-stem look is unappealing, cut the rosette off with 5–10 cm of stem and re-root as a fresh plant. The original cut stem usually re-shoots with 2–3 new rosettes from below the cut, producing a denser branching specimen.
Whole plant collapsing soft and watery
Symptom
Lower leaves and stem turn translucent, soft, and watery; whole plant flops over.
Cause
Root rot from summer overwatering — by far the most common Aeonium killer.
Fix
Often unsalvageable if rot reaches the rosette. If caught early at the basal stem, cut off all healthy upper rosette tissue with 5–10 cm of stem, callus for 1 week, and re-root as a fresh plant. The parent base typically does not recover.
Single rosette flowers and dies
Symptom
A mature rosette produces a tall yellow flower spike, then the rosette browns and dies after the spike finishes.
Cause
Aeonium is monocarpic — flowering rosettes die after blooming. This is normal biology, not a problem.
Fix
Cut the dead rosette at the stem; surrounding side-branch rosettes survive and the plant continues. To prevent flowering on a particularly precious rosette, cut the emerging spike out as soon as it is detected. In branched mature plants, occasional flowering and rosette loss is part of the natural cycle.
- Aphids on flower spikes
- Mealybugs at rosette centres
- Scale on woody stems
- Root rot from summer overwatering
- Black sooty mould following aphid infestations
Toxicity & safety
No reported toxicity in humans. Sap is mildly bitter but not irritant.
Aeonium arboreum — North Carolina Extension Gardener Plant ToolboxAeonium is not listed in ASPCA's toxic plant database. Generally considered safe for cats with no documented poisoning cases.
ASPCA Toxic and Non-Toxic Plants — Aeonium not listed in toxic databaseAeonium is not listed in ASPCA's toxic plant database. Generally considered safe for dogs.
ASPCA Toxic and Non-Toxic Plants — Aeonium not listed in toxic databaseWhy Aeonium grows in winter and sleeps in summer
Almost every popular succulent — Echeveria, Sedum, Crassula, Haworthia, Aloe, Sempervivum, Kalanchoe — follows the standard seasonal rhythm: actively growing in spring through summer, semi-dormant in winter, requiring less water in the cold months. Aeonium is one of the few outliers in cultivated succulents, and its inverted rhythm catches new owners out badly.
The reason is the plant's native habitat. The Canary Islands have a Mediterranean climate with mild wet winters and hot dry summers. Aeonium evolved to grow during the cool wet season (October–April) and weather the hot dry summer in protective dormancy (May–September). Leaves curl tightly inward in summer to reduce surface area; the plant essentially shuts down and waits.
Practically, this means three things. First, water more in autumn-winter than you would for echeveria or jade plant — Aeonium is actively growing and thirsty. Second, water dramatically LESS in summer than for any other succulent — perhaps once every 3–4 weeks just to keep roots alive. Third, expect the plant to look 'wrong' in summer: tightly closed rosettes, dropped lower leaves, no growth. This is not a problem to fix; it's the plant doing what it evolved to do.
Owners who treat Aeonium like Echeveria — water freely in summer, water sparingly in winter — kill it within a year through summer root rot and winter drought stress. Owners who learn the inverted rhythm find Aeonium one of the easier succulents because the active season aligns perfectly with the time of year when most people are home and attentive.
How 'Schwarzkopf' becomes the blackest plant in your apartment
Aeonium arboreum 'Schwarzkopf' (also sold as 'Zwartkop' in Dutch markets and 'Black Rose' in English-speaking markets) is famous for being one of the few plants in cultivation that genuinely looks black. In strong direct sun, mature rosettes are so dark they appear nearly black with a faint glossy sheen — almost more like a lacquered ornament than a living plant. The colour is created by a high concentration of anthocyanin pigment in the leaf surface, suppressing the underlying green chlorophyll.
Anthocyanin production depends on bright UV-rich direct sun. Without enough light, the plant doesn't bother producing the pigment — anthocyanins are metabolically expensive and only pay off as UV protection in genuinely sunny conditions. The practical consequence: 'Schwarzkopf' grown in a typical north-facing apartment window at 5,000 lux fades to bronze-green within a few months, and may green up almost completely over a winter. The same plant moved to a south-facing balcony for summer goes back to glossy black within 3–6 weeks.
The species is, unusually, sensitive to BOTH light intensity and the specific wavelength mix. Plants grown under standard LED grow lights (which are usually red-and-blue-heavy) often colour up less dramatically than plants grown under genuine sun, even at similar intensity. This is one of the few popular plants where 'natural sun is better than supplemental lighting' is genuinely true.
If you want the iconic near-black aesthetic at high latitudes, plan to summer the plant outdoors May–September on a sunny balcony or in a sun-baked window. Winter colour fade is acceptable as a seasonal feature; full black returns by June. If permanent black colour is non-negotiable, this is not the species for an indoor-only Nordic apartment — even with a humidifier and grow lights, you will not match the colour saturation of an outdoor specimen.
Aeonium arboreum belongs to a remarkable evolutionary radiation: roughly 35 Aeonium species evolved on the Canary Islands from a single common ancestor that arrived from North Africa around 5–10 million years ago. The islands' isolation, varied microclimates, and lack of competing species allowed Aeonium to diversify into ecological niches normally occupied by completely different plant families — there are mat-forming Aeonium, climbing Aeonium, tree-Aeonium, and tiny rock-crevice Aeonium. The genus is a textbook 'island radiation' alongside Darwin's finches and Hawaiian silverswords. The famous 'Schwarzkopf' cultivar was selected from horticulture material in Dutch nurseries in the 1950s and rapidly became one of the most widely grown succulents in the world.
Frequently asked · 5
Is tree aeonium (Aeonium arboreum) safe for cats and dogs?+
Yes — generally. Aeonium is not listed in the ASPCA's toxic plant database, and no poisoning cases are documented. The genus is widely considered pet-safe and is one of the better choices among ornamental succulents for households with cats or dogs that occasionally graze on plants.
Why is my aeonium closing into a tight ball in summer?+
Normal summer dormancy. Aeonium is one of the few popular succulents that grows in autumn-winter-spring and goes dormant in summer — the opposite of echeveria, sedum, or jade plant. Curled rosettes are protective: the plant reduces surface area to wait out heat and drought. No action needed; reduce watering dramatically (once every 3–4 weeks at most) and the rosette opens again in October–November.
Why is my 'Schwarzkopf' aeonium turning green?+
Light too low. The dark near-black colour depends on anthocyanin pigment that the plant only produces in bright UV-rich direct sun. Move to the brightest possible window with several hours of direct sun, or summer the plant outdoors on a sunny balcony from May–September. Colour returns over 3–6 weeks of bright exposure; existing fully-greened leaves regain colour as light improves.
How often should I water my aeonium?+
Depends on season — Aeonium has the inverted rhythm. Active season (October–April): water when the top half of the pot dries, roughly every 10–14 days. Summer dormancy (May–September): cut to roughly a quarter of normal — water once every 3–4 weeks just to keep roots alive. Watering an aeonium in summer the same as in winter is the single most common kill mechanism for this species.
Why did my aeonium flower and then die?+
Aeonium is monocarpic — flowering rosettes die after their tall yellow flower spike finishes. This is normal biology. In branched mature plants, only the flowering rosette dies; surrounding side branches survive and the plant carries on. To prevent flowering on a precious rosette, cut the emerging flower spike out as soon as you spot it. Single-rosette specimens that flower do not survive — propagate replacement rosettes from cuttings before flowering finishes.