How to Protect Plants from Frost This Winter

A sharp frost can undo a whole season of growing in a single night. But with a little planning, most plants come through a British winter without any trouble.

The key is knowing which plants are tough enough to look after themselves, which need a sheltered spot, and which have to come inside. It also helps to know that for many plants, cold, wet soil is a bigger danger than frost itself.

Here's how to protect plants from frost this winter, and which plants can safely stay outdoors.

Plants That Can Stay Outdoors All Winter

These fully hardy plants come through a normal British winter outside without protection, as long as they're in soil or compost that drains well:

• Hellebores, which even flower in the depths of winter
• Winter pansies and bellis
• Evergreen shrubs such as Euonymus, Aucuba, Viburnum tinus and Elaeagnus
• Bush and patio roses
• Heuchera and ivy
• Dogwood (Cornus), grown for its bright winter stems

Browse more tough plants in our winter plants and evergreen shrubs.

Plants That Need a Sheltered Spot

These plants are hardy in many gardens but can be damaged in a hard winter, especially in colder inland areas or in pots:

• Olive trees: fine outdoors in most southern and coastal gardens, but cold, wet compost kills more olives than frost. In colder or wetter areas, keep them in a pot you can move under cover.
• Cordyline: fine in mild, coastal and southern gardens, but a hard frost inland can cut it back or kill it.
• Bay trees in pots: usually fine outside, but the leaves scorch in cold, drying wind. Move potted bay somewhere sheltered in a hard winter.
• Camellias: the plants are hardy, but frost spoils the buds and flowers, so give them shelter from cold wind and early morning sun.
• Bedding cyclamen: they cope with a light frost in a sheltered pot, but a hard or long frost will kill them.
• Lophomyrtus and Diosma: only reliable outside in mild western and coastal gardens. Elsewhere, give them shelter or move them under cover.

Plants That Need to Come Inside

These plants won't survive a frost outdoors and need a bright, frost-free place such as a porch, conservatory, cool greenhouse or spare room:

• Citrus trees: lemons, limes and calamondins need to come in from about October until May.
• Bananas and Ensete: they need to be kept above about 7 to 10°C over winter.
• Geraniums (Pelargoniums): frost kills them outright.
• Bedding Fuchsias and Osteospermums: most are not frost hardy.
• Senecio 'Angel Wings': needs frost protection in all but the mildest areas.
• Dahlias, Begonias and Cannas: lift the tubers or rhizomes once the first frost has blackened the leaves, and store them somewhere dry and frost-free.

How to Protect Plants from Frost

1. Move pots to shelter

Plants in pots are much more exposed than plants in the ground, because the roots are only protected by a thin wall of compost. Group pots together against a house wall, where they're sheltered from wind and benefit from a little warmth.

2. Raise pots off the ground

Stand pots on pot feet or bricks so water can drain away. Waterlogged compost freezes solid and rots roots, and it's one of the main causes of winter losses.

3. Cover tender plants on frosty nights

If a hard frost is forecast, drape horticultural fleece over tender plants that can't be moved, and remove it during the day so they get light and air.

4. Mulch around the roots

A thick layer of mulch around the base of borderline plants helps protect the roots and crown from the worst of the cold.

5. Get the drainage right

Many plants that are hardy to cold are killed by sitting wet. Lavender, rosemary, Penstemon and Convolvulus all cope with cold much better than with soggy soil, so make sure they're in free-draining soil or a gritty pot.

6. Leave old stems on

Don't be too quick to tidy. On plants such as Penstemon, leaving the old stems on until spring helps protect the crown over winter.

What to Do After a Frost

If plants get caught by frost, don't panic. Let frozen plants thaw slowly, and don't cut off damaged growth straight away, as it helps shield the healthy growth underneath from the next frost. Wait until spring, when new shoots appear, then trim back to healthy growth. Many plants, such as Fatsia, shoot away again even after the leaves have been damaged.

Frost Protection: Your Questions Answered

What temperature is too cold for plants?

It depends on the plant. Fully hardy plants cope with a normal British winter outside, but tender plants such as geraniums are killed by frost, and tropical plants such as bananas need to stay above about 7 to 10°C.

Should I cover my plants on frosty nights?

Cover tender plants that can't be moved with horticultural fleece when a hard frost is forecast. Hardy plants don't need covering.

Can olive trees stay outside in winter in the UK?

In most southern and coastal gardens, yes, in a sheltered, sunny spot with very free-draining compost. In colder or wetter areas, it's safer to keep them in a pot you can move under cover.

Can winter pansies survive frost?

Yes. Winter pansies are fully hardy and keep flowering whenever the weather lifts.

Ready for Whatever Winter Brings

A little preparation now means your plants will come through winter safely and be ready to grow away in spring. For more seasonal jobs, see our November gardening checklist, and for colour that can cope with the cold, see how to plant winter pots that last until spring.

Every plant we sell is grown in Britain by growers we know, including the Yorkshire nursery that grows most of our garden plants. We choose them for the quality of what they grow, check every plant by hand before it's packed, and send it out ready for your garden.