Back in 2014 we had some very strong winds across the country. The wind was so strong it uprooted a tall Eucalyptus tree in our garden, and after the initial cracking noise of the rootball, the tree seemed to come down in slow motion, right on top of a large herbaceous border. Fortunately, it was late winter/early spring, so the tramping of large size 10s from our tree surgeon did little damage to the perennials underground.
Wind is one of the gardener’s worst enemies and plants have either adapted to cope with strong gusts or soon become battered.
How wind can damage the garden
During winter, evergreen plants get wind scorch, caused by cold winds that also dry out the soil.
Wind can cause plants to sway excessively, pulling and tugging on their roots. This continual movement interferes with the roots’ ability to remain grounded within the soil, “root rock”, which reduces the plant’s ability to absorb water, leading to severe water stress and even death. Wind affects the growth and development of plants in many ways.
Strong winds can also damage plants by breaking them and distorting their growth. It lowers the air temperature around plants, which reduces their rate of growth.
While good air circulation is essential in the garden for preventing a build-up of fungal spores that lead to plant diseases, a strong wind can be devastating to plants, as it causes leaves to become desiccated and die, and weak branches to break.
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“Thigmomorphogenesis” is a slow developmental change in the shape of a plant subjected to continuous mechanical stress (i.e. wind).
When trees bend in the wind, for example, growth is usually stunted, and the trunk thickens.
Windblown rain can spread spores from infected plants to healthy ones, quickly inhibiting their ability to sustain healthy growth and plant size.
Wind can also weaken the roots’ grip on the soil, caused by the movement of the stem so that the plant is partly lifted out of the ground – this is known as “wind rock”.
Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapour and is released into the atmosphere.
Transpiration is essentially the evaporation of water from plant leaves. Transpiration also includes a process called guttation, which is the loss of water in liquid form from the uninjured leaf or stem of the plant, principally through water stomata.
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Wind is a great contributor to transpiration. A 5mph wind will increase still-air transpiration by 20 percent; a 15mph wind will increase still-air transpiration by 50 percent.
Some plants have adapted for wind pollination. They have small, light pollen, which is carried by the wind, and have feathery stigmas to catch the pollen, such as Betula and Ambrosia artemisiifolia.
Wind also increases the turbulence in the atmosphere, thus increasing the supply of carbon dioxide to the plants resulting in greater photosynthesis rates.
How to use plants to protect the garden from wind
In the long-term, wind can be re-directed or slowed down by creating a windbreak or shelterbelt.
A hedge, tall trees, a woven willow hurdle or a semi-permeable barrier across the direction of the prevailing wind will help reduce the physiological and wind damage to other plants. Windbreaks reduce the velocity of the wind and therefore create a favourable micro-climate and provide shelter to beneficial pollinators.
The more branches there are on a tree, the better the wind is diffused throughout it to keep it upright.
Shelterbelts are for larger gardens, where tall trees are planted in 3 or 4 staggered rows. Acer campestre, Carpinus betulus, Rosa rugosa, Pinus nigra, or Phyllostachys felxuosa make excellent windbreaks. In addition, mulching will stop water loss from the roots and soil.
In the short-term, cut back plants that are prone to wind rock, such as shrub roses, Lavatera and Buddleia, by between a third and half of their height in the autumn and bring vulnerable plants like Olea europaea indoors.
Always avoid the temptation of building walls and solid structures to slow down wind.
With a solid structure, the wind is forced over the top with increased turbulence, which can cause severe damage to neighbouring plants and properties.
It is, therefore, better to plant trees and shrubs, such as rowan, birch, aspen, dogwood, juniper and pine.
Best plants for a windy garden
Shrubs can easily be incorporated into planting schemes. Try growing Berberis, Blackthorn, Broom and Elaeagnus.
When it comes to ornamental grasses and herbaceous perennials there are many to choose from, but some are more wind tolerant than others.
The sea thrift, Armeria, grows on slopes and banks close to the sea and is battered by coastal winds and is therefore perfect at the front of a border.
Plants that naturally sway with the slightest breeze make good specimens, such as Stipa, Calamagrostis, Panicum, Carex and Sesleria grasses. Crambe maritima and Crambe cordifolia send up sprays of white flowers, while the fiery blends of Crocosmia sway on their arched stems.
Thistles and eryngiums of all kinds work well in windy gardens.
Try growing Eryngium agavifolium or Eryngium alpinum. For late summer colour and flowers that dance on the wind you cannot beat the windflower or the Japanese anemone.