Mediterranean Garden Society’s: Making a Dry Garden

April 20th, 2009  |  Published in Water Conservation

article 002 Mediterranean Garden Societys: Making a Dry Garden

What is a dry garden?

A dry garden is one that receives little or no irrigation, using plants that are adapted to the dry summers characteristic of regions with a mediterranean climate.

Why make a dry garden?

Because water is a precious natural resource which is likely to become scarcer (and more expensive) as changes in the climate bring even hotter and drier summers to some parts of the world.  And of course because dry gardens are in keeping with the mediterranean environment and looks good throughout the year.

What sort of plants can one grow in a dry garden?

Trees, shrubs (including many climbers), sub-shrubs (including many aromatic plants), bulbs, winter or spring-flowering annuals and some herbaceous perennials.  There are many thousands of plants native to the various mediterranean-climate regions of the world which are adapted to dry summer conditions, and other regions with pronounced dry seasons offer many more.

What can’t one grow?

Lawns and plants from temperate climates, which will die without summer watering.  And don’t forget your own winter conditions-some plants ideal for dry summers won’t tolerate much frost, for instance, while others will.

How do mediterranean plants survive without water in the summer?

Apart from bulbs and spring-flowering annuals, which finish flowering and disappear below ground (bulbs) or set and die (annuals) as the summer heat begins, mediterranean plants withstand dry summers because their growing period is in autumn, winter and spring, when they can rely on natural rainfall.  In summer they suspend growth.  Many have leathery, glossy, downy or silvery-grey leaves, which help them to reduce water loss from the leaves.  Their variety of foliage and structure makes many mediterranean plants interesting even when they are not in flower.

What happens if I water them?

Some dry-climate plants will rapidly die if watered in summer.  Others will survive but will be shorter-lived than if they were given no water, and some accept some water without ill effect.

So no water at all?

Once established, many dry-climate plants will indeed need no summer water at all.  Others will benefit from deep watering at appropriately spaced intervals, for example once a month.  However, during their first summer or two, before they have become established (developed a good root system and become accustomed to their new soil and location), newly planted plants will need deep watering once every two or three weeks or so.

What is deep watering?

A lot of water given infrequently is very much better than a little water given often.  The reason is that frequent application of small amounts of water encourages plants to develop their roots near the surface of the soil, whereas widely spaced application of copious water allows the water to penetrate deep into the soil and encourages the plants to put down deep root, thus enabling them to withstand drought better.  One good way to give deep watering is to make a large watering basin, about 20cm (8in) deep, around the plant when you plant it (or around a group of smaller plants).  You then fill this basin to the brim and allow the water to seep gradually deep into the soil.

Summer deciduous:  bare but not dead

Some Mediterranean plants become dormant in summer and lose all their leaves when they are given no water.  (Examples are the medic, Medicago arborea, and the tree germander, Teucrium fruticans.)  These plants may look dead, but they are not – as soon as the first autumn rains arrive they will put out new leaves again.  When planting a dry garden you might want to place such plants in the background rather than in the foreground.

A few tips:

  • Plant in autumn:  Always plant in autumn so that your new plants can get the benefit of the winter rains during their first growing season.
  • Choose small plants:  Choose small and stock plants rather than letting yourself be tempted by large specimens in full flower.  Small plants will become established better and faster and in a couple years will have overtaken any larger ones that you were unable to resist.
  • Drainage:  Dry-climate plants hate sitting around with their feet wet in winter and thus need well-drained soils.  To ensure good drainage, cultivate the soil deeply before planting and, if your soil is heavy, incorporate liberal amounts of horticultural grit(sand) and/or gravel.
  • Prevent surface evaporation:  To prevent the evaporation of moisture from its surface, cover soil with a thick (at least 10cm/4in) layer of mulch.  This may be either inorganic (e.g. shredded garden waste) or inorganic (e.g. gravel or pebbles).  Inorganic mulches have the advantage that they are free-draining and thus suitable for plants which dislike too much winter wet – many plants whose natural habitat is the stony ground of mediterranean hillsides are particularly happy with a gravel mulch.  Leave the watering basin un-mulched during the plant’s first year.
  • Where to find plants:  Unfortunately many nurseries and garden centers, particularly around the Mediterranean Basin do not stock a good range of dry-climate plants.  (However, if their customers go on asking for them, they soon will.)

The Mediterranean Garden Society focuses on the wise use of water to maintain plants native to mediterranean climate regions, accustomed to a cycle of wet winters and dry summers, as the planet adjust to warmer temperatures and less predictable drought cycles.

For more information on the Society and a membership application form, write to the above address or visit the MGS website:  www.mediterraneangardensocity.org

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