Commonsense Rules for Flowers in Drought

By for CAES News
Last year's drought may have you wondering if it's worth going to the garden center this spring. And forecasters say the drought isn't over.

Before you put your trowel away, though, remember that many of our grandmothers successfully grew flowers in droughts. They never gave up. They just used common sense.

Following simple rules, you can have a colorful garden without violating watering restrictions or spending precious free time holding a garden hose.

Plant Early

For perennials, "early" means autumn. Perennials planted in April don't have time to grow sufficient roots. So you have to water more often. That strategy isn't wise, given the likelihood of watering bans.

Fall-planted perennials have all winter to build roots. They withstand drought better because they absorb water more efficiently. They will bloom and grow with half the care.

For annuals, "early" means as soon as the soil is warm enough for that species and frost chances are past. For most annuals, the best planting time is around April 1 in south Georgia and May 1 in the north Georgia mountains.

Waiting until June delays root development, forcing you to water annuals more often.

Prepare the Soil

Mixed with most Georgia soils, organic matter does many good things. It allows more air spaces to form, letting water penetrate deeper. The roots will follow the water.

It also makes the soil looser and lets roots grow through soil more easily. Deeper roots are cooler. And cooler roots use up fewer sugars. That leaves more for the plant to use to grow, flower and withstand a long drought.

Normally, add at least 2 inches of organic matter to a flower bed each spring. This spring, though, you might try at least 4 inches. Composted bark and homegrown compost are excellent materials.

Mulch Heavily

Unmulched gardens let the sun beat down on the soil, and hot soils evaporate water fast. Wind, too, easily blows away water vapor near the soil surface.

With an extra deep layer of mulch, you can reduce the evaporation driven by heat and almost eliminate moisture loss to wind.

Here's a mulch recipe that worked great in my garden last year. Place 4 inches of composted pine bark around newly planted annuals. This coarse material has a lot of surface area. That's great for capturing rainfall and cooling the soil, but bad for wind- and sun-driven evaporation.

Then place 2 inches of pine straw on top of the bark. This layer intercepts and reflects some of the heat. Most important, it reduces air flow over the bark.

Hand-spread these layers after planting the annuals. They settle down to about 4 inches after a week or so.

Water sparingly

Once your mulch is in place, you won't need to water as often. But a sprinkle of rain or a pass over with the garden hose won't wet the soil underneath all that mulch.

It takes a steady, lengthy watering to thoroughly saturate the soil. If you've prepared the soil and mulched properly, you won't need to water more than once a week. But when you do water, water thoroughly.

If you're on water restrictions, don't water just because it's your day. Overwatering killed more garden plants last summer than the drought.

Water no more often that once a week. Your prepared soils will dry out very slowly. The roots will respond to slight drying by growing deeper.

Applying 2 inches of water per square foot will saturate the soil and keep prepared soils moist for at least seven and usually 10 days.

Finally, use plants that can take the heat. If you do all these things with native and other drought-resistant plants, you'll be well prepared for the worst the Georgia summer can hand you.

Paul Thomas is a horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.