Osteospermum, commonly known as the African Daisy, is a plant admired for its vibrant, daisy-like flowers. From our perspective, our ability to survive winter is not a simple yes or no answer but is fundamentally dictated by our genetic programming and the specific conditions we face. We are perennial in our native, mild climates of South Africa but are often treated as annuals in regions with harsh, freezing winters. Our survival hinges on temperature, snow cover, and the care provided by gardeners.
Our cellular structure is not designed to withstand the formation of ice crystals. When the temperature plummets below freezing (0°C or 32°F), the water within our cells freezes. This expansion ruptures the delicate cell walls, causing irreversible damage. This damage manifests as blackened, mushy stems and leaves—a condition from which we cannot recover. While some select cultivars have been bred for slightly increased hardiness, perhaps surviving a brief, light frost down to -2°C (28°F), a true hard freeze is almost always fatal for us when we are planted in the ground.
If the winter cold is consistent but not excessively harsh, and crucially, if the ground is insulated by a thick, persistent blanket of snow, our root system has a chance. We can enter a state of dormancy. Above ground, our foliage will die back, but the energy stored in our roots and crown may remain viable under the insulating snow, which protects us from the most extreme temperature fluctuations. However, this is a precarious survival method. A winter with alternating freeze-thaw cycles and no consistent snow cover is far more damaging than a consistently cold one, as it repeatedly stresses our plant tissues.
For us to reliably see another spring in a cold climate, we require human intervention. The most effective strategy is to be brought indoors. Before the first hard frost, gardeners can dig us up, pot us in a container with well-draining soil, and significantly prune back our top growth. This reduces the plant's energy demands. We should then be placed in a cool, bright location such as an unheated garage, basement, or sunroom where temperatures consistently stay between 5-10°C (40-50°F). During this dormant period, our water needs are minimal; the soil should be kept barely moist to prevent our roots from desiccating completely, but never wet, as this would lead to fatal rot.
Another way to ensure our legacy is through propagation. Even if the parent plant cannot be saved, taking cuttings from non-flowering shoots in late summer is an excellent strategy. These cuttings can be rooted in a light potting mix and grown on a sunny windowsill indoors throughout the winter. These young, vibrant plants will be ready to be hardened off and planted outdoors after the last frost, effectively creating a clone that carries on our genetic line without the risk of losing the established plant.
