African daisies (Osteospermum spp.) are native to South Africa, where they thrive in warm, sunny climates with well-draining soil. Their natural habitat is characterized by mild winters and hot summers, making them perennial in USDA hardiness zones 9-11. In colder regions, they are often grown as annuals or require special care to survive winter.
African daisies are not frost-tolerant and can suffer damage or die when temperatures drop below freezing (32°F or 0°C). Their succulent-like leaves and stems are vulnerable to cold, which can cause cell rupture and lead to wilting or rot. In zones 8 and below, overwintering strategies are essential to keep them alive.
In marginally cold regions (e.g., zone 8), African daisies may survive outdoors with protection. Apply a thick layer of mulch (3-4 inches) around the base to insulate roots. Cover plants with frost cloth or burlap during freezing nights. Ensure soil is well-draining to prevent waterlogging, which can exacerbate cold damage.
For zones 7 and below, moving African daisies indoors is the safest option. Before the first frost, dig up the plants and pot them in containers with fresh, well-draining soil. Place them in a bright, cool (50-60°F or 10-15°C) location, such as a sunroom or near a south-facing window. Reduce watering to prevent root rot.
Trim back African daisies by one-third in late fall to remove dead or leggy growth. This reduces stress on the plant and encourages compact, healthy regrowth in spring. Avoid heavy pruning, as it may weaken the plant before winter. Remove any diseased or pest-infested foliage to prevent indoor spread.
Indoor overwintering can invite pests like aphids or spider mites. Inspect plants regularly and treat infestations with insecticidal soap or neem oil. Ensure good air circulation to prevent fungal diseases. Avoid overwatering, as damp conditions can lead to root rot or mold.
After the last frost, gradually acclimate African daisies to outdoor conditions. Start by placing them in a shaded, sheltered spot for a few hours daily, increasing exposure over 7-10 days. Once hardened off, replant them in the garden or leave them in containers with fresh soil and balanced fertilizer.
For gardeners without indoor space, consider propagating African daisies from cuttings before winter. Root 4-6 inch stem cuttings in water or potting mix, then grow them indoors under grow lights. This ensures new plants are ready for spring while avoiding the hassle of overwintering mature plants.
Watch for yellowing leaves, wilting, or stunted growth, which indicate cold damage or improper care. If outdoor plants show signs of stress, provide additional mulch or cover. Indoor plants may need more light or less water. Healthy plants will resume vigorous growth once warm weather returns.
