Horticulture Fact Sheet

University of Georgia Cooperative Extension

Coping with Watering Restrictions
in the Landscape

Gary L. Wade, Extension Horticulturist

Residents in many counties throughout Georgia are currently facing restrictions or bans on outdoor water use. When watering restrictions are imposed, there are a number of things homeowners can do to help plants make the best use of water in the landscape.

First, make certain plants have a generous supply of mulch over their roots. Three to five inches of mulch will help hold moisture in the soil and will prevent evaporation from the soil surface. Fine-textured mulches, such as pine straw, mini-nuggets and shredded hardwood mulch do a better job of conserving moisture than coase-textured mulch. Apply mulch to as large an area as possible under the plant, remembering that the roots of established woody ornamentals extend two to three times the canopy spread.

Another practice to conserve moisture in the soil is to use a leaf rake to gently pull back existing mulch (being careful not to disturb the surface roots of plants). Then, place two to three sheets of newspaper on the soil surface, moisten it, and rake the mulch back over the newspaper. Newspaper will serve as an added barrier to moisture loss. However, avoid placing the newspaper more than two to three sheets thick because a thick layer of newspaper will actually inhibit the penetration of rainfall, irrigation water and fertilizer to the roots. Moisten the newspaper soon after placing it on the soil. Otherwise it may draw moisture from the soil.

Avoid cultural practices that encourage new water-demanding growth. Fertilization is not wise during extended dry periods because fertilizers are chemically salts and can actually dehydrate the roots of plants. Routine pruning also stimulates new growth and should be avoided during dry periods. However, some selective pruning may be necessary when a plant wilts and begins showing leaf-scorch and death of branches. In this case, pruning helps the plant reduce its foliar demand on the roots for water.

When you can water, directional watering with the hand-held hose to apply water only to those plants that show signs of wilt will help conserve water. Priority should be given to newly planted trees and shrubs (those installed within the past four months). Water these plants every 7 to 10 days during the absence of rainfall.

Annual and perennial plants generally have a higher demand for water than woody ornamentals. However, wait for them to wilt before watering. Some perennials, like sedum, gaura, daylilies and ornamental grasses are extremely drought tolerant and can survive long periods without rainfall or irrigation (see attached list of drought-tolerant plants). Plants will tell you when they need water when the leaves wilt, droop or turn a grey-green color.

If a total ban on outdoor watering is imposed and you can not water anything, the best advice is to cut back annual and perennial flowers that wilt in an effort to reduce their moisture loss and make certain they are well mulched. This will reduce the demand for water by the top on the root and will help keep the root system alive. A light pruning of shrubs that become severely wilted will also help them conserve moisture and survive the dry period.

Avoid shallow watering. The worst thing you can do for plants is to water them frequently and shallowly. Shallow frequent watering encourages a shallow root system and reduces the drought tolerance of plants.

When you can water, water between 9 pm and 9 am. Less water is lost to evaporation when watering in the evening or at night. Watering during this time will not encourage diseases since the foliage is usually wet anyway from the night-time dew.

Direct water to the roots - not the top. When you water, direct water to the roots and avoid wetting the foliage of ornamental plants if possible. Wetting the foliage not only encourages diseases but also results in evaporative loss of water.

Drip or trickle irrigation or a soaker hose are efficient ways of watering. Drip irrigation uses 50% less water than conventional sprinkler irrigation and applies water slowly and directly to the root system.

A timer installed on outdoor faucets to control the period of irrigation will prevent the unnecessary use of water.

Use drought tolerant plants. Many of our Southern ornamental plants have an inherent tolerance to drought and can survive long periods of limited rainfall. Table 1 is a listing or ornamental plants known to have above average tolerance to drought.

Table 1. Ornamental Plants Known to Have Above-Average Drought Tolerance.
Trees
Common Name Botanical Name
Bald cypress Taxodium distichum
Bur oak Quercus macrocarpa
Cabbage palm Sabal palmetto
Chaste tree Vitex angus-castus
Cherry laurel Prunus caroliniana
Chestnut oak Quercus prunus
Chinese pistache Pistacia chinensis
Crape myrtle Lagerstroemeia indica
Deodarcedar Cedrus deodara
Ginkgo Ginkgo biloba
Goldenrain tree Koelreuteria paniculata
Hollies Ilex spp.
Honeylocust Gleditzia triacanthos
Japanese zelkova Zelkova serrata
Japanese pagoda tree Sophora japonica
Lacebark elm Ulmus parvifolia
Laurel oak Quercus laurifolia
Live oak Quercus virginiana
Loquat Eriobotrya japonica
Magnolia Magnolia grandiflora
Needle palm Rhapidophyllum hystrix
Pin oak Quercus palustris
Pindo palm Butea capitata
Pond cypress Taxodium ascendens
Redbud Cercis canadensis
Shumard oak Quercus shumardii
Smoke tree Cotinus coggygria
Sweetgum Liquidambar styraciflura
Sycamore Platanus occidentalis
Tulip poplar Liriodendron tulipifera
Washington hawthorne Crataegus phaenopyrum
Water oak Quercus nigra
White ash Fraxinus americans
White oak Quercus alba
Windmill palm Trachycarpus fortunei


Table 1. Ornamental Plants Known to Have Above-Average Drought Tolerance. (cont.)
Shrubs
Common Name Botanical Name
Aucuba Aucuba japonica
Barberry Berberis sp.
Beauty bush Kolkwitzia amabilis
Beautyberry Callicarpa americans
Butterfly bush Buddlea davidli
Chaste-tree Vitex agnus-castus
Chinese photinia Photinia serrulata
Chinese holly Ilex cornuta
Cotoneaster Cotoneaster spp.
Crepe myrtle Lagerstroemia indica
Dwarf yaupon holly Ilex vomitoria 'Nana'
Euonymus Euonymus spp.
Firethorn (Pyracantha) Pyracantha coccinea
Flowering quince Chaenomeles speciosa
Forsythia Forsythia intermedia
Fragrant sumac Rhus aromatics
Glossy abelia Abelia grandiflora
Japanese barberry Berberis thunbergii
Jasmine Jasminum spp.
Juniper Juniper spp.
Oleander Norium oleanders
Osage orange Maclura pomifera
Pampas grass Cortaderia selloana
Pittosporum Pittosporum tobira
Quince Chaenomeles japonica
Spirea Spirea spp.
Strawberry bush Euonymus americans
Viburnum Viburnum spp.
Wax myrtle Myrica cerifera
Yaupon holly Ilex vomitoria


Table 1. Ornamental Plants Known to Have Above-Average Drought Tolerance. (cont.)
Vines/Ground Covers
Common Names Botanical Names
Asiatic jasmine Jasminum asiaticu
Bearberry cotoneaster Cotoneaster dammeri
Carolina jasmine Gelsemium sempervirens
Confederate jasmine Trachelospermum jasminoides
Creeping juniper Juniperus horizontalis
Daylily Hemerocallis spp.
Japanese clematis Clematis spp.
Juniper Juniper spp.
St. John's wort Hypericum calycinum
Thrift Phlox subulata
Trumpet vine Campsis radicans
Trumpet honeysuckle Lonicera sempervirens



Table 1. Ornamental Plants Known to Have Above-Average Drought Tolerance. (cont.)
Annuals/Perennials
Common Names Botanical Names
Annual phlox Phlox drummondii
Annual periwinkle Vinca rosea
Baby's Breath Gypsophila spp.
Black eyed susan (coneflower) Rudbeckia bicolor
Calendula Calendula officinalis
Cape marigold Calendula officinalis
Coreopsis Coreopsis spp.
Cornflower Centaurea cyanus
Cosmos Cosmos bipinnatus
Gaura Gaura lindheimeri
Gazania Gazania linean's
Globe amaranth Gomphrena globosa
Moss rose Portulaca grandiflora
Stonecrop Sedum spp.
Strawflower Helichrysum bacteatum




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Updated May, 2007