Protecting Your Plants from Frost in Winter: Effective Methods and Protection
Frost is the main cause of plant loss in the garden. But good protection can save the most delicate plants: potted citrus trees, olive trees, roses, hydrangeas or Mediterranean plants. This guide covers the effective methods — winter fleece, mulching, earthing up and pot protection — with the equipment and the calendar to prepare the garden well before the first frosts.
The equipment for protecting plants
- Winter fleece (non-woven) of 17 to 30 g/m² for plants in open ground
- Mulch: straw, dead leaves, shredded branches or bark
- A ridging hoe or simply soil to earth up the base of roses and fruit trees
- Bubble wrap, polystyrene or hessian to insulate the pots
- Garden cloches or cut plastic bottles for young plants
- Chalk line, secateurs and a few ties to hold the fleece in place
Knowing the needs of each plant
Not all plants react to frost the same way. Hardy plants like resistant perennials withstand frosts of -10 °C without protection. Semi-hardy plants (rosemary, lavender, some roses) withstand down to -5 °C in open ground. Frost-sensitive plants (citrus, olive trees, potted oleanders) must be protected as soon as the temperature approaches 0 °C. Classify your plants and protect the most sensitive first.
Protecting plants in open ground
- Mulch the soil over 10 to 15 cm around the plants: the soil stores heat
- Earth up the base of roses and fruit trees with soil over 20 to 30 cm
- Wrap the sensitive plants in winter fleece, without squeezing the foliage
- Fix the fleece to the ground with stones or staples so it does not blow away
- Remove the fleece during the day as soon as the temperature rises above 0 °C
Protecting plants in pots
- Bring the pots of frost-sensitive plants into a bright garage or a conservatory
- Insulate the pots left outside with polystyrene, bubble wrap or hessian
- Raise the pots on packers so that water does not pool under the base
- Group the pots against a south-facing wall to benefit from the heat of the wall
- Wrap the pot, not just the leaves: the roots are the most fragile
Acting during a cold snap
When a frosty night is forecast, a few simple measures limit the damage. Water the soil lightly before the night: damp soil releases heat. Put the protections in place the evening before and remove them in the morning once the thaw is well underway. For fruit trees in flower, a fleece placed at sunset avoids losing the flower buds. Never prune during frost: the cut freezes and weakens the plant.
The winter protection calendar
- Early November: mulch the flower beds and earth up the roses, bring in the frost-sensitive potted plants
- Late November: place the winter fleece over sensitive plants in open ground
- December to February: watch the forecast and put the protections in place on frosty evenings
- Late March: remove the fleece gradually in mild weather, keep it close for late frosts
- After the Ice Saints (mid-May): final removal and planting of annuals
Adapting the protection to the region
The level of protection depends on your climate. In a region with mild winters, a light fleece and a mulch are often enough for semi-hardy plants. In a continental or mountain climate, where frost can reach -15 °C, prefer a thick fleece (over 30 g/m²), generous mulching and systematically bringing the pots in. In damp, cold regions, the protections must also let air through: a plant under an airtight sheet without ventilation rots faster than it freezes. Observe your garden and adjust the protections according to previous winters.
The mistakes to avoid
- Placing a fleece or sheet in direct contact with the foliage: the frost burns it
- Leaving the protections on all day: without air or light, the plants suffer
- Not protecting the pots: their roots freeze far faster than in open ground
- Pruning frost-damaged branches during the frost: wait for the regrowth in spring
By combining mulching, winter fleece and good planting practices, you effectively protect your plants from frost and cold. The protections go on in autumn, come off in spring and your garden comes back in full form. Check your protections regularly during winter, and you will avoid unpleasant surprises at the first frosts.