How Do I Protect My Apricot Blossom from Frost?

Frost damage to apricot blossom is the principal reason apricot growing in the UK is so frustrating. The tree blooms in February or March — some of the coldest weeks of the year — and open flowers are killed at just -1°C. A single night of frost during peak bloom can destroy the entire year's crop in a matter of hours. Understanding how to protect blossom and how to recognise whether it has been damaged makes the difference between a harvest and another fruitless year.

How frost damages apricot flowers

Fully open apricot flowers are killed at around -1°C. The petals may survive and look unharmed, but the pistil — the central female part of the flower — is damaged at the base. When you look inside a frost-damaged flower you will often see the pistil has turned brown or black at its base. This is known as pistil death and is absolute — a flower with a blackened pistil cannot set fruit under any circumstances. On close inspection after a frost event, check ten flowers across the tree. If most show blackened pistils, the crop is lost for that year.

Covering with fleece

Horticultural fleece (30 g/m² grade) draped over a wall-trained tree provides approximately 2–4°C of frost protection. Drape it loosely from top to bottom and peg it to the ground or tuck it behind the tree. Keep the fleece off the wall slightly so a small air pocket traps warmth. Put covers on in late afternoon when a frost is forecast and remove them by mid-morning to allow pollinators access. Do not leave covers on through warm days — flowers need air circulation to prevent fungal problems, and pollinators need access to complete pollination.

Delaying blossom with shade

A wall-trained apricot on a warm south-facing wall blooms earlier — exposing it to more frost risk — than a tree on an east-facing wall. If you are planting a new tree, an east-facing aspect delays blossom by one to two weeks and significantly reduces frost risk. For existing trees on south walls, shading the wall with white shade cloth from late January delays bud break slightly.

After a frost event

If frost occurs during bloom, do not prune off any wood — assess the damage first. Check pistils in ten flowers across the tree. If half or more still show cream-coloured healthy pistils, partial fruit set is still possible. Hand-pollinate remaining healthy flowers on the first warm, sunny morning after the frost. If all pistils are blackened, the crop is lost for the season but the tree itself is unharmed.