In winter, evergreen plants are prone to wind scorch (also known as leaf scorch). This is caused by cold winds and poor soil conditions resulting in scorched, brown, dry leaves.
Plants affected: Evergreen shrubs, trees and tall perennials
Main causes: Cold, drying winds combined with difficult soil conditions
Timing: Usually in winter
What is wind scorch?
Gardens in exposed locations are often subjected to strong winds. In addition, winter soil conditions may be difficult: dried out by strong winds, waterlogged by heavy rain and frozen by cold weather. The combined effect of all these problems is seen as wind or leaf scorch on evergreen trees, shrubs and perennials.
Scorch shows up in a number of ways;
- Scorched leaves have brown, desiccated edges or may be entirely brown and dry
- Wind scorch may be worst in exposed areas or on the windward side of the plant
- Large-leaved evergreens are affected worse than small-leaved plants, and pot plants are at particular risk
When the wind blows, the rapid air movement causes moisture to be lost from foliage and from the soil. And, if the soil is also dry, plants may not be able to replace moisture lost from leaves fast enough. Likewise, plants are also unable to extract moisture from frozen or waterlogged soils. The leaves soon become desiccated and scorched.
Strong winds can cause physical damage to plants and garden structures. Providing wind protection will slow the speed at which wind will pass a plant, reducing the amount of water lost from the leaves.
Windbreaks can be erected using netting, proprietary windbreak materials, or woven hurdles. These filter the wind, reducing its strength. A screen filtering 50 to 60 percent of the wind is ideal. Be aware that solid barriers such as garden walls and fences will deflect the wind over the top and may cause damaging turbulence only a short distance from the barrier.
Hedges and trees can also be used to protect shrubs from wind scorch. Plant shrubs in the lee of a garden hedge. Deciduous hedges filter the wind, but beware of dense evergreen hedges which may deflect the wind, causing some turbulence on the leeward side. Woodland species such as camellias, Acer palmatum and pieris are best planted beneath trees.
Place plants in pots against a sheltered house wall, but be careful to avoid a position where buildings create a wind tunnel.
Protect small plants over winter with well-anchored horticultural fleece. Insulate containers by wrapping them with bubble wrap.
Reduce water loss
Mulch the soil around plants with bulky organic mulches such as bark chips to reduce the drying effect of wind on the soil.
And in the spring…
Cut out the scorched foliage from broadleaved evergreen trees and shrubs in the spring as growth resumes. Conifers will often fail to regrow from badly damaged shoots and should not be pruned.
To encourage recovery, feed plants in spring with general-purpose fertiliser.
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