John McWilliams teaches plant biology at Oklahoma Baptist University in Shawnee.

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Dealing With Drought
by John McWilliams       #Weather

Over the past months, most areas of the country have set records for heat and drought. While the experts debate the “whys” and “hows,” the rest of us are stuck with the bottom line — it’s harder to grow things. Extreme temperatures and lack of moisture stresses most garden and landscape plants that would normally be considered tried-and-true standards. In addition, the availability and expense of irrigation has become problematic in many regions. There have always been cycles in the weather; however, successful growers have learned to anticipate them and to deal with them in stride. There are several strategies that home gardeners can employ to take the edge off of extreme summer conditions.

Irrigating more efficiently…

A dependable source of brilliant color, crapemyrtle is able to tolerate summer heat in style.

Often found in wet, flooded areas, bald cypress holds up well during periods of drought.

Lantana is one of the most drought-tolerant perennials available. It provides color and form in even the hottest spots.

Many varieties of sedum are now available, and all of them thrive through drought.

Portulaca, or moss rose, is an easy annual that will punctuate the driest landscapes with color.

Ornamental sweet potato now comes in a variety of leaf colors. Blazing sun only makes the spreading vines more attractive.

Plants need water at their roots — any place else, and water is wasted and often even detrimental. Therefore, any irrigation system that delivers water to plant roots without wasting water in unnecessary areas is most effective. Soaker or drip hoses are always better at this than general overhead watering. Also, keep track of the amount of water delivered. There’s no need to saturate soil far away from the root regions. Some plants can stand a little drying in between waterings, so experiment with skipping a few days, if possible.

Smarter plant placement…

Do you have a favorite plant that has a higher water requirement? Plant it on the eastern or northern side of your house, where the soil is likely cooler and moisture evaporates slower. Utilize the shade of larger trees or other buildings. Plant tougher species on the southern or western side of your house or in highly exposed areas where irrigation is impractical.

Keeping moisture in the soil…

One of the easiest and most effective ways to preserve soil moisture is by mulching. True, there are “best practices” to be aware of with mulches, but usually, any mulch is better than no mulch. Applying bark, straw or other material around plants will keep the soil cooler and significantly decrease surface evaporation. Mulching can greatly expand your selection of plants that can withstand extreme weather. With trees and shrubs, make sure the mulched region covers the entire root area, usually the diameter of the canopy itself.

Using drought-tolerant species…

When most people speak of drought-tolerant plants, they usually aren’t thinking specifically of cacti and succulents (although these can be used very effectively in many landscapes). Ideally, gardeners prefer plants that can thrive in a wide range of conditions, but are not threatened by prolonged periods of dry, hot weather. These are typically species that are adapted to growing in regions where heat and dryness is a natural part of the climate.

Some species that can stand up to drought…

Trees: bald cypress (Taxodium distichum), bur oak (Quercus macrocarpa), Shumard oak (Quercus shumardii), golden raintree (Koelreuteria paniculata), gingko (Gingko biloba), pines (shortleaf, Pinus echinata, and Virginia, Pinus virginiana)

Shrubs: juniper (Juniperus spp.), nandina (Nandina domestica), sumac (Rhus spp.), hedge roses (Rosa spp.), yaupon holly (Ilex vomitoria), crapemyrtle (Lagerstroemia spp.)

Annuals: moss rose (Portulaca grandiflora), common purslane (Portulaca oleracea), globe amaranth (Gomphrena globosa), baby’s breath (Gypsophila paniculata), cosmos (Cosmos bipinnatus), gaillardia (Gaillardia spp.), black-eyed Susan (Rudbeckia hirta), sweet alyssum (Lobularia maritime), ornamental sweet potato vine (Ipomoea batatas), dusty miller (Artemisia stellerana)

Perennials: lantana (Lantana camara), sage (Russian sage, Perovskia atriplicifolia, and other sages in the genus Salvia), agastache (Agastache spp.), lamb’s ears (Stachys byzantina), sedum (Sedum spp.), yarrow (Achillea millefolium)

Vegetables: cowpeas (Vigna unguiculata), okra (Abelmoschus esculentus), sweet potato (Ipomoea batatas)

As water resources and other environmental issues come to the forefront, and the climate pendulum swings to the hotter, dryer side, more and more people are rethinking traditional garden and landscape practices. Some home gardeners are making the switch to native species exclusively or exotic species that require less irrigation and pampering. The term xeriscaping is often used to describe this strategy. It takes a change of mindset for most of us to make this leap. Sometimes it means accepting the idea that Bermudagrass perhaps grows best in Bermuda, not southern Arizona. And maybe wild black-eyed Susan is just as pretty as African daisies. Mother Nature offers many attractive landscapes in a variety of climates, and we can often improve our gardens and make life easier by following her examples.



Posted: 07/16/12   RSS | Print


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