How to Protect Plants From Frost

Frost can damage or kill tender plants, ruin spring blossom, and set back growth. A few simple precautions can save your plants from cold damage.

Which plants need protection?

• Tender perennials: Dahlias, cannas, pelargoniums, fuchsias.
• Mediterranean plants: Olive trees, citrus, agapanthus, some salvias.
• Exotic plants: Tree ferns, bananas, palms.
• Early spring flowers: Camellias, magnolias, fruit blossom.
• New plantings: Recently planted shrubs and perennials are more vulnerable.

Horticultural fleece

Fleece is the most versatile frost protection. It lets light and water through while providing several degrees of frost protection.

• Drape over plants and secure at the base with stones or pegs.
• Use multiple layers for extra protection.
• Remove during the day in mild weather to prevent overheating.
• Can be left on for extended cold periods.

Mulching

A thick mulch protects roots and the crown of plants from freezing:

• Apply 10-15cm of bark, straw, or leaf mould around the base of plants.
• Particularly important for borderline hardy plants like agapanthus and some fuchsias.
• Pull mulch back slightly in spring as growth begins.

Moving containers

Potted plants are more vulnerable than those in the ground because the roots are exposed to cold on all sides.

• Move tender plants into a greenhouse, conservatory, or porch.
• Group pots together against a house wall for mutual protection.
• Wrap pots with bubble wrap or hessian to insulate the roots.
• Stand pots on feet to prevent waterlogging.

Wrapping plants

For plants too large to move, wrap them in place:

• Tree ferns: Stuff the crown with straw and wrap the trunk with fleece.
• Bananas: Cut back leaves, wrap the stem with straw held in place by chicken wire.
• Palms: Tie leaves together and wrap with fleece.

Cold frames and cloches

These provide excellent protection for smaller plants:

• Cold frames protect overwintering plants and early sowings.
• Cloches protect individual plants or rows of vegetables.
• Improvise with upturned plastic bottles with the bottom cut off.

Timing matters

• Check weather forecasts and protect plants before frost arrives.
• Late frosts in spring are often more damaging than winter cold because plants are in active growth.
• Frost pockets – low-lying areas where cold air collects – are more at risk.

After frost damage

• Do not prune frost-damaged growth immediately – it protects the plant from further damage.
• Wait until spring when you can see where new growth is emerging.
• Many plants recover from frost damage that looks severe.