Aeonium

Aeonium is a genus of succulent, subtropical plants belonging to the family Crassulaceae. They are often called “tree houseleeks” due to their resemblance to a small tree or shrub. Native primarily to the Canary Islands, they are popular in horticulture for their striking, rosette-shaped leaves and architectural form.

Key Characteristics

• Appearance: Aeoniums are known for their fleshy, waxy leaves arranged in dense, symmetrical rosettes. These rosettes sit at the end of a stem, which can be bare or branched, giving the plant a tree-like appearance. The leaves come in a wide range of colors, from solid green to shades of yellow, red, bronze, and a dramatic deep burgundy or black.
• Growth Habit: Unlike many other succulents, aeoniums have a distinct growing season. They are winter growers and often go dormant in the hot, dry summer months. During dormancy, the rosettes may close up tightly to conserve water.
• Flowers: When a rosette reaches maturity, it will produce a central flower stalk with a cluster of small, star-shaped flowers, typically in shades of yellow, white, or pink. An important thing to note is that most aeonium species are monocarpic, meaning the rosette that flowers will die after blooming. However, most species branch or produce offsets, so the plant as a whole will continue to live.

Care and Growing Conditions

• Light: Aeoniums thrive in bright, indirect light or a spot with morning sun and afternoon shade. While they can tolerate full sun in cooler climates, intense, direct sun can cause their leaves to scorch, especially in the summer.
• Soil: As with other succulents, excellent drainage is crucial. Use a well-draining soil mix specifically formulated for cacti and succulents, often a mix of organic matter and grit, perlite, or sand.
• Watering: Aeoniums have different watering needs depending on the season. Water thoroughly during their active growing season (fall to spring), allowing the soil to dry out completely between waterings. Reduce watering significantly during their summer dormancy to prevent root rot.
• Temperature: Aeoniums are not frost-tolerant and are best suited for USDA hardiness zones 9-11. In colder climates, they are excellent container plants that can be brought indoors for the winter. They prefer cooler temperatures during their growing season, ideally between 65-75°F (18-24°C).
• Pruning and Propagation: Aeoniums can become “leggy” over time. To maintain a more compact shape and encourage branching, you can “behead” the rosettes by cutting the stem. These cuttings can be planted to create new plants. Allow the cut end to dry and callus for a few days before planting to prevent rot.

Popular Varieties

• Aeonium arboreum: A common species that forms a shrubby, branching plant with bright green rosettes.
• ‘Zwartkop’ (or ‘Black Rose’): A popular cultivar of Aeonium arboreum known for its striking, almost black rosettes.
• ‘Sunburst’: A beautiful variegated cultivar with large rosettes of pale yellow, white, and green stripes, often with pink tips.
• Aeonium tabuliforme: Known as the “Dinner Plate Aeonium” because its rosettes are perfectly flat and wide, lying almost on the ground. It is a monocarpic species that does not branch.