Whenever we get some snow, gardeners start to panic that it will damage their plants. But snow isn’t the problem that people think - in fact, snow acts as a bit of an insulation and helps to protect plants. The only damage it does is to evergreens and other plants, where its weight can weigh down branches causing damage and even snapping them. So, when it snows, go outside and gently knock the snow off the leaves and branches.
No, it’s not the snow that should concern you - it’s frost and cold temperatures. Plants left out in the garden at this time of year are generally hardy or more-or-less so, and nearly all should survive temperatures down to -5°C (23°F), and many to much lower temperatures. But, if the temperature drops a lot below this, then you should consider protecting borderline hardy plants. t’s not only how low the temperature drops, it’s also for how long. A day or so at -5°C rarely does damage to hardier plants, but a longer period or several weeks of it can be more damaging, especially if it’s combined with very cold, strong winds. New plants that are not fully established are more vulnerable, and can be damaged or killed in a cold spell.
Vulnerable plants can be given an enclosure made from windbreak netting lined with garden fleece, while not-so-hardy wall shrubs are insulated from the cold by spreading a sheet of fine-mesh netting over the plants and stuffing it with insulating material, such as straw or dry leaves. Alternatively, you could cover the plants with a layer or even double layer of well secured garden fleece.
For many plants, it’s the damage to the roots that causes more problems than that to the top growth. Many borderline shrubs and climbers benefit from having their roots protected during prolonged cold spells by covering the surface of the soil with a thick insulating mulch. This is particularly important while the plant is becoming established, during the first few seasons after planting. It’s plants in containers that are particularly susceptible, because their roots are above ground level and not insulated by the soil, and even otherwise hardy plants can be damaged if their roots freeze solid for prolonged periods. Move the containers into a greenhouse, shed or garage or move them close to the protection of a south-facing house wall. Alternatively make ‘duvets’ of bin liners filled with insulating material such as torn-up newspaper, polystyrene chips or roof insulation. Also make sure the pots are kept off the ground by standing them on pot feet to aid drainage, prevent waterlogging and damage to the roots and pot through excess freezing. It’s all a matter of keeping an eye on the weather - and dealing with it promptly before problems start. Sometimes easier said than done!