Coping with our coastal winds

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Cape Town – Wind can be very damaging to plants, drying out foliage and stunting the growth of shrubs and trees.

Wind can also damage plants by breaking their stems or branches or whipping away flowers and fruit. Strong salt and sand-laden wind scorches leaves.

“A windbreak creates what is essentially a micro-environment in your garden to allow the more tender plants to establish,” said Tessa de Wet of Plants on 6th Nursery in Melkbosstrand. “It also protects the garden from salt damage, if you live near the ocean, and can act as a privacy screen if correctly placed.”

 

Types of windbreaks

Windbreaks can be constructed or natural. Constructed windbreaks may be permanent, like perimeter fencing, a gate or trellis, or the windbreak may provide temporary protection for young plants. Constructed windbreaks can be used in conjunction with natural barriers like trees and shrubs.

Before you can create a windbreak, you need to know the direction of the prevailing winds.

“The south-easter blows in summer from around August through to February and the north-westerly blows in winter.”

 

Correct placement

“It is advisable to do a thorough site analysis,” said De Wet. “Factors such as existing buildings, walls and trees will influence your decision. Look at your neighbour’s property. You should also consider the shade aspect of a windbreak as you may find it creates more shade than you want. Remember the winter sun is lower than in summer.

“The narrow areas between boundary walls and houses can become a ‘wind tunnel’, where the wind is trapped and accelerates, so this would be an obvious position for a windbreak.”

In terms of placement, also consider your view. If trees and shrubs grow too high, they will obstruct it.

 

Constructed windbreaks

Allan Haschick, specialist horticulturist and author of Coastal Gardening in South Africa says: “The best constructed windbreaks are semi-permeable, such as trellis, picket fencing, breeze blocks and palisade, as these break the force of the wind. High solid walls create turbulence and often a vortex, which causes damage to plants growing in the ‘shadow’ of the wall.”

Young trees and shrubs need support to give them a chance to develop a strong root system. Shade cloth can be used to provide a temporary windbreak for them.

Build a temporary windbreak for an individual plant using shade cloth (20-30 percent weave) and gum poles. Place the windbreak in a V-shape around the plant; the middle pole should face the direction of the strongest wind.

The shade cloth must be pulled tight across them and properly secured.

 

Natural windbreaks

Using plants to create a windbreak is both practical, affordable and looks good in the garden.

“As you want shelter from wind as fast as possible, speed of growth is a major factor to consider,” said Haschick. “Many of our local dune or coastal shrubs make excellent hardy windbreak subjects. Windbreak plants ideally have pliable or flexible branches that move with the wind.

Plants with fine needle-like foliage, like fynbos, also work well.”

Pioneer plants are tough, fast-growing and provide shelter from various conditions, including wind or extreme heat.

“In harsh, windy conditions, pioneer plants can provide protection from wind, salt spray and prevent soil erosion,” said Haschick. “Many pioneer species are often weedy or not desirable garden plants but they can be used successfully as temporary wind shelter plants, which can then be removed once the more desirable ‘sheltered’ plants have become established.”

 

Establishing a natural windbreak

When selecting plants for your windbreak, consider their size. Nick Stodel, managing director at Stodel’s Nurseries, says bigger, more established plants will provide a immediate effect in blocking the wind.

“Planting the trees in a row and allowing them to grow close, forming a hedge, would be the best solution to the wind problem,” said Stodel.

The minimum spacing for trees or shrubs that grow to a height that can block the wind is 1m apart.”

Remember to stake all new plants. Strong winds can loosen the root ball, preventing the plant from becoming properly established.

 

Plants that withstand the wind:

Trees:

Wild olive (Olea europaea subsp. africana), coastal silver oak (Brachylaena discolour), salt and pepper tree (Myoporum laetum), white milkwood (Sideroxylon inerme) and Henkel’s yellowwood (Podocarpus henkelii).

Shrubs: Hedging provides an effective defence against wind: dune-crow berry (Searsia crenata), blombos (Metalasia muricata), Eugenia/ Australian brush cherry (Syzygium paniculatum), dune salvia (Salvia africana-lutea), spekboom (Portulacaria afra) and hibiscus.

Groundcover:

Groundcover helps to stabilise sandy soil and prevent it blowing away. Consider pig’s ears (Cotyledon orbiculata), sour fig (Carpobrotus edulis), vaalbietou bush (Chrysanthemoides incana), arctotis, osteospermum, and gazanias.

Indigenous plants:

Camphor bush (Tarchonanthus camphoratus), hiccup nut (Combretum bracteosum), crane flower (Strelitzia reginae), false olive (Buddleja saligna), waterberry (Syzygium cordatum) and the wild plum (Harpephyllum caffrum).

Plants that tolerate salty air: statice (Limonium perezii), karo (Pittosporum crassifolium), dune aloe (Aloe thraskii), confetti bush (Coleonema spp.), ostepermum, lavender, rosemary and pelargoniums.

Independent HOME, Kay Montgomery

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