After an “exceptionally warm” October and the beginning of November, many garden plants have yet to develop their winter hardiness. This has left them very vulnerable to frost, which is expected to arrive in the UK this weekend.
David Denyer, Eflorist’s flower and garden expert with over 35 years of experience, has shared why the first frost is often the most dangerous and how to protect your plants. The expert said: “The first frost often catches gardeners off guard because it arrives while your garden still looks full of life.
“Many plants have been putting out new growth after a warm summer and wet September, but that growth is full of water and has soft cell walls.
“When frosty temperatures arrive, the water inside your plants freezes and expands, rupturing those cells and leaving them blackened and unable to recover.
“Later in winter, most plants naturally harden off and become more resilient, but the first frost usually arrives before they’ve had the chance to do that, which is why it can cause so much damage.”
According to the expert, plants most susceptible to the frost include half-hardy bedding plants such as begonias and dahlias.
Plants in pots are also much more at risk than those in the ground because the soil in containers cools and freezes much quickly.
The expert added: “Garden soil acts like a layer of natural insulation, while roots in pots are left exposed to sudden temperature changes, especially if they’re in terracotta or thin plastic containers. Even hardy perennials can struggle if their roots are exposed to freezing conditions.”
To “protect” your plants from frost overnight, David said gardeners need to slow down how quickly they lose the warmth they’ve absorbed during the day.
“Covering your more vulnerable plants with fleece, cloches, or even an old sheet will trap a thin layer of warmer air around them and stop it escaping overnight.
“Just remember to remove the covers again in the morning so that air can circulate and the plants can breathe. If covers are left on during the day, moisture can build up underneath, leading to rot and mould.
“For potted plants and hanging baskets, move them up against a wall where possible. This is because brick and stone walls hold onto warmth during the day and release it slowly at night, which can help raise the temperature around your plants by a few degrees, which is often enough to stop frost forming.”
Adding mulch, bark, or fallen leaves around the base of your plants can also help insulate the soil, keeping moisture and temperature levels steady.
