Mediterranean Garden Society



Drought

The photograph at the top of this page shows wild flowers growing in the desert at Wadi Mujib, Jordan (Photo Jorun Tharaldsen)

The word "drought" has two slightly different meanings. On the one hand, it is often used to refer to the hot dry summer period in mediterranean-climate regions when there is no rainfall, which may last for three or more months. This kind of drought is regular and expected. On the other hand, it refers to an unusual state of dryness caused by insufficient rainfall or even a complete lack of rain during what is normally the wet season.

It is hard to predict how climate change will affect mediterranean areas, but we may very well have to face hotter, drier or longer summers. We shall thus need to be increasingly careful about our use of water in the garden.

This has been the subject of many articles in the journal, by authors from different parts of the world. We are reproducing a selection of them here.

Olivier Filippi gives an introduction to the topic taken from his book The Dry Gardening Handbook.

In her own garden on a Balearic island, Heidi Gildemeister, the doyenne of waterwise gardening, demonstrates in practice that it is possible to have a beautiful and green garden which requires very little water. Read article.

For additional reports and articles on this subject please check out the (non-responsive) MGS Archive.

Drought: An Introduction 

by Olivier Filippi
Extract taken from The Dry Gardening Handbook published by Thames & Hudson.

Drought has always been considered as a limitation for gardens. We have all been influenced by the temperate climate garden model, in which thriving shrubs and lush perennials surround a perfect lawn. Every month, gardening magazines make us dream of superb gardens, generally in northern Europe. Beautiful photographs in gardening books promote an image of rustic scenes, where roses and clematis grow intertwined. Yet in areas with a mediterranean climate these ideal conditions are a dream that can never be fulfilled. Instead of gentle light we have brutal sunshine; instead of rich soil we have the stony garrigue. The drier the climate, the harder it seems to make a garden. It is as if we are engaged in a ceaseless battle against a hostile environment.

Stony Mediterranean growing conditions

Nevertheless, dry climates offer extraordinary gardening possibilities. Paradoxically, thanks to a long tradition of a passion for gardening and botanical research, it is in England that the largest collections of drought-resistant plants have been amassed. These plants are jealously cared for as if they were precious rarities, grown in raised rock gardens to ensure perfect drainage and sometimes cultivated under glass to protect them from an excess of winter wet. Garden-lovers flock to the Royal Horticultural Society's famous garden at Wisley, south of London, to admire a sophisticated rock garden re-created under glass. Its treasures include plants that often no one bothers even to glance at on our Mediterranean roadsides – Rhodanthemum from Morocco, Erodium from Greece or Sideritis from Turkey. While English plantsmen pride themselves on their collections of plants for dry conditions, gardeners further south are desperately watering their lawns, but achieve nothing more than a mediocre imitation of an English garden.

Rather than drought, it is often the misguided use of irrigation that limits the range of plants in mediterranean gardens. Many dry-climate plants are in fact easy to grow if we respect the conditions of their native habitat, but become extremely capricious as soon as we try to water them in summer. The cistuses of the garrigue, the ceanothuses that cover the hillsides of California or the capers that billow down Sicilian cliffs quite simply cannot tolerate the combination of heat and moisture. Irrigation during our blazing summers generally proves fatal to them.

Santolina in the wild

If you water your garden during the hot weather you will never be able to grow the full range of plants adapted to the mediterranean climate. The beautiful Salvia candelabrum will be nothing more than a fantasy, the magnificent Fremontodendron covered in golden flowers won't stand a chance. Don't bother even to dream of the vibrant blue of Lithodora fruticosa or of the soft, silky pink flowers of Ebenuscretica: irrigation will kill them just as surely as a powerful dose of herbicide. Automatic watering systems are one of the worst inventions of the modern mediterranean gardener. You may think you are making life easier while in fact all you're doing is limiting the range of plants that can survive in your garden. Without realizing it, you are helping to reduce the plant palette to uniformity. In region after region, gardens end up all looking much the same, having lost the individual identity that is linked to their particular climate and soil conditions.

Olivier Filippi’s garden near Montpellier, southern France

What will happen if you stop watering? Well, yes, the plants that need water will die, one after another. So what will be left? Everyone dreads the idea of a miserable-looking garden, where dusty borders contain only a few spiny plants, and wretched shrubs eke out a meagre existence. We feel instinctively that water brings luxuriance and variety, and that dryness restricts our gardening possibilities. Yet exactly the opposite is true. Most gardeners are unaware that the natural flora of mediterranean-climate regions is a lot richer than that of temperate regions.

Photographs by Olivier Filippi. Olivier Filippi's book (translated from the French by Caroline Harbouri) is available from Amazon.co.uk.


Not All Plants Are Equally Thirsty

by Heidi Gildemeister
From The Mediterranean Garden No 8 Spring 1997

As never before, Mediterranean gardeners are faced with lack of water, not always due to summer drought. This may take newcomers by surprise. For my own garden, water being scarce has become a way of life. In summer, our water tank invariably runs dry with many weeks of drought to go. I remember how concerned I was when first faced with this uncomfortable situation and how I cried over the inevitable losses. Meanwhile, I have become confident since I know that my garden will survive. It has done so year after year, turning lusher as time goes by. An array of recipes lets it come through dry summers. Grouping plants according to their water needs is one of the prominent ones.

You will achieve important savings in water if you divide your garden into areas with high, moderate and low water needs. In each of these three areas you group plants with similar moisture requirements and rearrange those areas where drought-tolerant species have been planted next to thirsty ones. By giving your plants the right amount of water, you use the precious liquid where it is beneficial and avoid all unnecessary waste. You can also try to reduce the area with a high water use, especially if it is not essential to your garden. These simple guidelines, sometimes called hydrozoning, are worth gold to gardeners who have to make do with little water.

Heidi Gildemeister’s garden in Mallorca
(photo courtesy of Phaidon)

Many gardeners group their plants by leaf texture and flower colour; they deliberate on height and the flowering period or enthuse about variegation. The specific quantity of water required by each is not always considered. However – even if water were not scarce – this is a crucial aspect.

When you divide your plantings into areas, remember that certain good-humoured plants tolerate life in high- or low-watering zones alike – as long as they are planted according to their requirements. Abelia and Escallonia, for example, favour dappled shade and that is where they demand the least water. Other plants are less resilient and require specific doses. Providing plants with the water they really require promotes their health and is an important step in avoiding disease.

Remember that those plants which over the years have been given lavish watering (while in fact they needed little) cannot be weaned from one day to the next. Their roots need time to adapt to foraging for water on their own – which may require two or three seasons.

Often it is felt that a rich picture results only from plants which require, or are given, lavish watering. But this is not so. In the garden that I tend, watered and unwatered zones are alike in their colourful exuberance. It all depends on the right choice of plants which will give their best as long as they grow under conditions that suit them well. (This may mean sun or shade, protection from wind, above all generous mulching and well-draining soils.)

Even if one has all the water in the world, grouping the plants according to the water needs benefits the garden. This so-called hydrozoning facilitates, for example, the installation of watering equipment, since it is difficult to water correctly areas where plants with high and low water requirements live next to each other. Where feasible, all watering equipment should be installed before planting. Thus you know how far water reaches and can choose plants accordingly. Less expensive and easier to maintain, such gardens suit those who have little time at hand.

Three different groups are suggested, but your garden does not have to have all three.

The area with a low water use 
This area needs the least water and suits a tight water budget. Here you use all those plants which do not require more than annual rainfall. However, apply additional water until newly planted vegetation has been established. Depending on the size of the specimen at planting time, this may mean a year or so. Remember that drought-tolerant plants require excellent drainage and good ventilation and that most thrive in sun.

Such plantings include a delightful variety of plants whose flowers and fragrance offer pleasure throughout the year. In my garden, I use for this section plants from all Mediterranean climate regions. Winter rain takes care of them and generally carries them through summer without further attention (remember summer dormancy?). Countless unthirsty plants such as BupleurumCoronillaCeanothusCotoneasterCynara or Ruta qualify to make up the non-irrigated section, for example, in a ‘natural garden’. Most herbs thrive in this area. Or take advantage of the native vegetation found locally and reintroduce wild flowers. None of them requires summer water. This area could, but does not have to, be situated furthest from the house. Plants on the borderline of your garden need not be as manicured, since mostly you see them from a distance. Should you desire a formal approach, clipped cypress, myrtle and lavender cotton offer themselves.

The area with a moderate water use
The second group includes those plants that need more water than rainfall supplies, but not much more. Depending on the conditions your garden offers and the plants you have chosen, this may mean (in the hottest months) a once to twice weekly watering. In my own garden, I fare well with a weekly summer watering for this zone and maybe an additional application after drying winds. Your own observation will help you to determine frequency and quantity for your own garden.

Many plants you may want to grow in this second group do not come from a summer-dry Mediterranean climate and require watering in summer (AbutilonFatsiaFuchsiaHebeHostaPhygelius). Their healthy growth and attractive flowers do not lag behind those plants which demand ample supplies. Closely planted and generously mulched (to retain humidity in the soil), they will present a cheerful picture which may provide a link between a natural garden area and a thirsty, water intensive zone.

The area with a high water use
In this water-intensive area you grow plants which require the most water. These may come from tropical lands or from regions with summer rain (BegoniaCamelliaHibiscus rosa-sinensisHydrangea). It may also mean a lawn of moderate size, thirsty annuals, containers with exotics or a vegetable garden. Place your cherished high water plants next to the lawn and water them together with it for an intimate, luxuriant scene.

To take advantage of every drop of water, plant closely, mulch generously, and place where the least evaporation through wind and sun occurs. Diminishing the size of this zone trims down your water bill effectively. But whatever you decide on, use the water at your disposal how and where it will give you most joy.


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