Keeping gardens green when the sun doesn't stop shining

Global warming, we are told, will make weather extremes more commonplace in future. The summer heatwave has been a challenge to all of us, with brown lawns and withered plants spoiling the beauty of our treasured outdoor spaces. We all need to take a hard look at our gardens and decide how best to adapt and minimise the impact of drought and extreme heat.

Some factors are outside our control, such as soil type or garden aspect. But whatever soil we have, from light and sandy to heavy clay, or whether the garden is exposed or sheltered – we need to improve our garden’s capacity to withstand long periods of drought. It is all a matter of degree and how far we want to go, but a combination of measures can make a big difference.

Watering is not the answer. Although new plants must be watered in and given extra water until established, it is all about improving the moisture holding capacity and fertility of the soil and choosing plants more suited to dry, sunny and windy conditions. I would recommend Beth Chatto’s inspiring book The Dry Garde to anyone seriously interested in the subject, as it also contains a valuable list of drought tolerant plants.

If you are starting a bed from scratch, then you must dig in a good supply of humus, regardless of soil type. It could be garden compost, well-rotted manure, rotted leaves, in fact anything which will add moisture retentive humus. When planting, put whatever’s left into each hole, and mix well with the soil. When trying to establish drought-loving plants, use fertiliser sparingly – it will encourage too much top growth and they will survive much better on a thin diet.

Mulching is extremely important, but don’t put it on a dry soil! Having created the sponge to hold water in the soil, we don’t want the sun and wind to dry it out too quickly. This is where mulching comes in. It serves two important functions: (1) to prevent water evaporating from the soil, and (2) to prevent weed seedlings emerging.

Beth Chatto recommends using straw around her shrub areas and pulverised bark, a much finer material, around her herbaceous plants. Straw put down in Autumn, after some good rainfall, will break down and add valuable nitrogen to the soil. Pulverised or composted bark is expensive, but there are cheaper alternatives such as spent mushroom compost, wood chippings, well-rotted manure and spent hops. As long as the material is bio-degradable, it will add nutrients to the soil. And be as generous as you can afford to be – at least 2in deep, preferably 3in.

Having sorted out the soil, use drought-resistant plants to build up resilience to the threat of climate change. Plants that survive the scorching Mediterranean sun are going to do well, including Cistus, rosemary, juniper, Genista, Spanish broom and so on. Grey leaved plants are ideally adapted to resist drought and include many varieties, such as Artemesia, Brachyglottis, Euphorbia, Helichysum (the curry plant), Lavender, Lychnis coronaria, Perovskia, and Santolina. Loads of herbs come from the Mediterranean so a herb bed would be ideal.

Space prevents me from going any further, but information about drought-tolerant plants is readily available on-line. September is a good time to start dividing established perennials and buying new plants, so why not incorporate some of the principles discussed above to start your drought-resistant garden? And remember to put your garden debris and vegetable waste in the compost bin because you’re going to need as much of this precious material as you can make!

Malcolm Linfield

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