Strategies to Beat the Heat -- and Drought -- of the Long, Scorching Summer

What started as a cool spring in the Washington region has turned into a hot, dry summer.

Less than four inches of rain fell at Reagan National Airport from June 1 to Aug. 4. The norm for is about seven inches. The Potomac River is flowing at about half its normal volume for August.

Another sign of a drought: The price of local produce is increasing.

We have been repeatedly teased this month with forecasts of "scattered showers" and "the possibility of thunderstorms," but these storms have rarely materialized. We need a steady, all-day rain to penetrate the soil and get the moisture to the roots, where plants can use it. Torrential rain doesn't irrigate plants as well as a light soaking rain. At this point, however, any precipitation will help. Until it arrives, we need to take more care with water in our gardens.

Reduce the impact that hot, dry weather has on your plants by planting flora adapted to the average moisture and soil type of your region. Natives are a good idea but not the only answer for beautiful, lush gardens.

Gardens can be designed and planted to withstand warmer, drier conditions. Even if your landscape is well established, gradual changes can make a difference. For example, a rain garden is probably the best step you can take to keep water where it falls. It's an area that has been prepared so water percolates efficiently into the soil and around the plant roots and the excess can soak into the soil and help recharge aquifers -- the fresh water that flows underground in huge natural reservoirs. Take care, though, because some aquifers have been breached with pesticides and other chemicals in recent years.

When you choose plants, follow the principles of water-efficient landscape design. The generally accepted word for this is "xeriscaping," which means planting for dry conditions, but it has come to mean installing drought-resistant plants and delivering water to them efficiently. When you replace plants in an established garden, install those that will withstand dry conditions in dry areas and wet conditions for moist sites.

Design for shade and coverage, as well. Evaporation from plant leaves has a cooling effect. Ideally, plant material, including trees, shrubs, perennials and annuals, should cover 75 to 80 percent of the soil.

Group plants with similar water requirements. Some perennials and grasses that can tolerate drought include coreopsis, autumn joy sedum, lavender, gaillardia, blue switchgrass, blue oat grass and Elijah blue fescue. Abelia, caryopteris, cotoneaster, viburnum, potentilla and spiraea are more drought-tolerante shrubs.

An established planting of black-eyed Susans, liatris and purple coneflowers is also drought tolerant and might not require watering every week, depending on their exposure. In contrast, moisture-loving cardinal flower, blue star amsonia, blue flag iris, acorus and other plants that prefer cool, protected sites could wilt and dry without irrigation.

Install plants in a growth medium that is at least one part compost to two parts existing soil. Earth that is rich in organic material will give flora its best shot at beating the heat and drought. Appropriate use of mulch can slow evaporation of water from plants' root zones. Use organic mulches, such as compost or bark. Never mulch against woody plant trunks, and spread not more than two inches thick.

But sometimes plants still have to be watered, especially during their first year or two as they get established.