Glossy medlars are commercially available as winter-hardy. But the cold season can endanger the evergreen shrubs. In order not to disturb the biological processes, the right winter protection is necessary.
The photinia is hardy, but gets along badly without water
Frost tolerance of evergreen shrubs
As an evergreen plant, the photinia keep their leaves throughout the winter. In the spring, the old leaves are replaced. The bushes will sprout again. The photinia originally came from the warmer regions of Asia. Their range extends from the Himalayas through China to Thailand and India. Here, many Photinia species grow in regions with temperatures below freezing. Although the commercially available varieties are often considered hardy, particularly long periods of cold can damage the plants.
water cycle in winter
The plants are endangered by ground frosts that reach deep into the earth. As long as there is a thick layer of snow on the ground, temperatures down to -20 degrees Celsius pose no danger to most varieties. The snow acts as an insulating layer and prevents the ground from freezing. The roots of the medlar can absorb water from the ground, which its evergreen leaves need in winter.
Unlike deciduous shrubs, the water cycle in evergreen plants does not stop in winter. Water evaporates from the leaves. So that there is no deficit, the roots have to provide replenishment. This only works in an ice-free ground. As soon as the roots lie in a frozen substrate, water absorption is stopped. Drought stress develops, which manifests itself in the drying and dying of the leaves. In the case of long-lasting ground frosts, the buds also dry out, so that the new leaf sprouting and the flowers are endangered.
Protection from the cold
Winter protection can help. Older plants that have developed a dense root system cope better with the icy winter months than young plants. If the minus temperatures last for several weeks, you should protect the plant.
Winter protection for outdoor shrubs:
- Garden fleece as evaporation protection for the leaves
- Brushwood or fir branches insulate the ground
- Watering before winter fills up the reserves
Young plants should initially be cultivated in tubs so that they can overwinter in a mild place without frost. Protect the leaves from excessive evaporation with a transparent fleece. Bubble wrap is ideal for wrapping the pot.