Gardens with Dry Soil

Every garden is dry sometimes, but in some climates and with some soil types, moisture is always at a premium. Scant rainfall typical of many places in the West, as well as in areas where late-summer droughts create temporary desert conditions, sets the stage for a garden created with dry soil in mind.

The same gardening techniques that serve desert gardeners apply to areas with sandy soil, which dries out quickly no matter how much rain falls, and they can also be used to good effect on a slope that is difficult to water because of runoff. In these and other types of dry, sunny sites, you can still have a colorful garden by using plants that are adapted to these conditions and by using the special planting techniques described here.

Dodging the Drought

Summer is always the most stressful season in a dry garden, but you may be amazed at how easy it is to succeed at growing "off-season" plants, which are quenched by winter rains. Even in high deserts, spring-flowering bulbs like crocuses, daffodils, and tulips will blissfully bloom in spring with little or no supplemental water during their most active period of growth, which is from late fall to late spring.

Later, when Mother Nature turns up the heat and turns off the water, these plants quietly go dormant before the hot summer season. In dry climates with mild winters, take advantage of cold-tolerant annuals that can be grown from seed sown outdoors in fall, such as larkspur, poppies, and even cosmos. They'll need supplemental watering until they germinate, unless the season is wet, but any soil holds water longer at the end of the year than during summer.

Plants for Parched Gardens

All gardens need supplemental water once in a while, but growing plants that are natural water misers, such as cotoneaster, stonecrop, and yucca, keeps this need within practical limits. Look to nature for clues to help you find promising plants. Prairies and mountainsides as well as arid parts of the world have contributed a wealth of beautiful plants that will thrive in a garden like yours.

And they are not all cacti! Garden-worthy plants with succulent, water-holding leaves like portulaca and stonecrop are specially adapted to dry environments because their thick leaves work like small water reservoirs. Silver-leaved plants, such as artemisia, Russian sage, and sim rose, reflect excess light, and the downy hairs on the leaves and stems of these and other plants shade and insulate them from the evaporative power of the sun. Deeply rooted perennials and grasses are good choices. Choose shrubs with small, waxy leaves, such as cotoneaster. Among annuals, those with papery "petals," which are really modified leaves called bracts, such as globe amaranth and zinnia, keep their fresh appearance through days of baking heat.

Sunken Garden Beds

Raised beds are a valuable asset in poorly drained or infertile soils, but you should take the opposite route for the plants you'd like to pamper in an arid garden. Beds that are slightly sunken are designed to collect rainfall and cast cooling shade over the soil. After lowering the soil level by a few inches, prepare a sunken bed the same way you would any other new planting site. Loosen the soil and amend it with compost. Besides making the soil more hospitable to plant roots, organic matter helps buffer the effects of chemical imbalances, such as excessive salt, which often builds up in dry-climate soils, and it also neutralizes acid or alkaline soil, conditions that can be harmful to many garden plants.

Mulching is the key to care-free gardening in dry soils. Choose a porous mulch that encourages water to quickly filter through and enter the soil. Large bark nuggets, rounded river rock, or other coarse mulch materials are good choices, lake care not to build up a thick layer, however. Plants adapted to dry conditions resent being smothered in mulch. A generous inch (3 cm) of mulch, spread evenly over the bed in spring, will do the trick.

Timely Transplanting

Even drought-tolerant plants need water during the first few weeks after transplanting, because their ability to survive with scant moisture depends in part on the presence of mature, far-reaching roots. There are several ways to reduce the time you must spend insuring that your dry-site garden is care-free from the very beginning.

Before removing a plant from its container, make sure that the soil in the pot is saturated. In addition to reducing transplanting trauma, wet roots slip free from pots more easily than dry ones. As a result, fewer roots are injured during transplanting, and every root is plumped up with water as you set the plant in place.
Whenever possible, set out new plants in the evening, so that they will not be immediately challenged by the drying effects of hot sun. Also look for periods when some cloud cover, or perhaps even rain, is in the weather forecast to undertake major planting projects, such as planting a large bed or setting out shrubs and trees.

If you must set out plants in bright, breezy weather, you can get them off to a strong start by covering them with temporary shade. Anything that filters sunlight will do, such as covering plants with bed sheets or a wooden lattice propped up by stakes. Cardboard boxes, weighed down with a stone, are great for popping over small shrubs or young annuals, and upside-down flower pots make good shade covers for small perennials. Remove the shade covers after 3 days, because as soon as the plants begin to grow, they will crave sunlight.