Aeoniums are distinctive succulents with rosette-shaped leaves. Originating from the Canary Islands and other Mediterranean climates, they prefer mild conditions. Understanding their temperature tolerances is important for successful growth and health.
Ideal Growing Temperatures
Aeoniums thrive within a specific temperature range. During the daytime, they prefer 65°F to 75°F (18°C to 24°C). Nighttime temperatures can be slightly cooler, ideally around 50°F (10°C). They flourish in environments that avoid extreme temperature fluctuations. These mild conditions encourage active growth and maintain their vibrant appearance.
Coping with Cold Temperatures
Aeoniums are not frost-hardy. Some varieties might tolerate brief dips to 25-30°F (-4 to -1°C), but prolonged freezing causes damage. Below 41°F (5°C), most varieties struggle. Freezing temperatures (below 32°F/0°C) cause cellular damage, leading to mushy, discolored, or black leaves. This occurs because water in the plant’s cells expands when frozen, rupturing cell walls.
To protect aeoniums from cold, move potted plants indoors before the first frost. If outdoors, choose sheltered locations or provide covers like horticultural fleece for insulation. Reducing watering during cooler months also helps; wet soil combined with low temperatures increases root rot risk. In many climates, aeoniums enter winter dormancy, where growth slows significantly.
Managing High Temperatures
Aeoniums often enter summer dormancy, a natural mechanism to conserve energy and moisture. Temperatures consistently above 85°F (29°C) can trigger this dormancy or stress. During dormancy, rosettes may close, and growth slows or ceases, sometimes with leaf drop. Prolonged heat and direct sun can cause scorching, wilting, or brown patches on leaves.
To manage heat, provide afternoon shade, especially during peak summer hours. Move potted plants to a shadier spot or use shade cloth to mitigate intense sunlight. Good air circulation also helps prevent heat stress. During summer dormancy, reduce watering; plants are not actively absorbing moisture, and overwatering can lead to root rot.
Identifying and Responding to Temperature Stress
Aeoniums communicate discomfort through various visual cues, regardless of whether the stress comes from cold or heat. Signs of temperature stress include droopy, limp, discolored (brown or black) leaves, or unusual leaf drop. Rosettes may also close or shrivel, indicating the plant is conserving moisture or protecting itself. Sunburn, appearing as white or brown patches, indicates too much direct sun.
If temperature stress is observed, adjust the plant’s environment by moving it to a location with more appropriate temperatures and light. Gradually reintroduce cold-stressed plants to warmth, and for heat-stressed plants, ensure adequate shade and air circulation. Hold off on watering until the plant recovers, as stressed plants are more susceptible to root rot. Allow the plant time to recover in a stable environment before resuming normal care.