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Gardening How-to Articles

Drought-Proofing Your Garden: Essential Water-Saving Strategies and Plant List

Severe to extreme drought conditions are affecting large portions of North America, including the Atlantic Coast from Maine to Georgia, the Plains states, and significant parts of the Southwest as well. New York City's experience has been typical of many urban and suburban areas. On April 1, the city declared a Stage 1 Drought Emergency, introducing numerous restrictions on industrial, municipal, and domestic water use. Gotham's gardeners are only allowed to water their lawns every other day for two hours in the morning and the evening, and they can only water the rest of their plants using hand-held watering cans or low-flow irrigation equipment.

Don't be fooled by those days of plentiful rain in April and May, because water reservoirs in much of the East are still well below normal capacity. And there has been no easing of water restrictions. We still need an abnormally high amount of rainfall for water supplies to get back on track by next year.

A drought emergency is a time to take steps to substantially reduce water use in the garden. It's also a good time to take stock of our gardening practices and to consider how out of tune they are with normal fluctuations in yearly rainfall and snowfall. Below are some tips on how to conserve water while coaxing your plants through the current drought. These are followed by longer-term solutions that will help make your garden more compatible with natural precipitation patterns.

Drought-Tolerant Plants

Deciduous Trees

  • Amelanchier arborea, Shadbush, Downy serviceberry
  • Carpinus caroliniana, American hornbeam
  • Carya ovata, Shagbark hickory
  • Cotinus obovatus, American smoketree
  • Crataegus species, Hawthorns
  • Diospyros virginiana, American persimmon
  • Halesia carolina, Carolina silverbells
  • Liquidambar styraciflua, American sweetgum
  • Prunus x cistena, Purpleleaf sand cherry
  • Quercus species, Oaks (many species)
  • Sassafras albidum, Sassafras
  • Tilia species, Lindens

Shrubs

  • Aesculus parviflora, Bottlebrush buckeye
  • Arctostaphylos uva-ursi, Bearberry
  • Aronia arbutifolia, A. melanocarpa, Chokeberries
  • Caryopteris x clandonensis 'Bluemist', Clandon bluebeard
  • Ceanothus americanus, New Jersey tea
  • Chaenomeles x superba, Flowering quince
  • Cornus racemosa, Gray dogwood
  • Corylus americana, American filbert
  • Coylus avellana 'Contorta', Harry Lauder's walking stick
  • Cotinus coggygria, Smokebush
  • Erysimum 'Bowles Mauve', Wallflower
  • Hamamelis virginiana, Witch-hazel
  • Hydrangea paniculata, Panicle hydrangea
  • Itea virginica, Virginia sweetspire
  • Lavandula angustifolia, Lavender
  • Lespedeza thunbergii, Bush clover
  • Myrica pensylvanica, Bayberry
  • Perovskia atriplicifolia, Russian sage
  • Philadelphus coronarius, Mockorange
  • Prunus maritima, Beach plum
  • Rhus copallinum, Shining sumac
  • Rosa rugosa, R. glauca, R. nitida, R. carolina, and other species, Species roses
  • Santolina chamaecyparissus, Lavender cotton
  • Symphoricarpos albus, Common snowberry
  • Symphoricarpos orbiculatus, Coralberry
  • Syringa species, Lilacs
  • Vaccinium angustifolium, Lowbush blueberry
  • Viburnum dentatum, Arrowwood
  • Viburnum lentago, Nannyberry

Needled Evergreens

  • Abies concolor, White fir
  • Cephalotaxus harringtonia, Japanese plum yew
  • Chamaecyparis pisifera, Sawara false cypress
  • Juniperus species, Junipers (most species)
  • Picea species, Spruces (most species)
  • Pinus species, Pines (most species)
  • Taxus species, Yews (most species)
  • Thuja occidentalis, Eastern arborvitae

Broadleaf Evergreens

  • Ilex crenata, Japanese holly
  • Ilex glabra, Inkberry
  • Ilex x meserveae, Meserve holly
  • Ilex opaca, American holly
  • Mahonia aquifolium, Oregon grape

Vines

  • Aristolochia macrophylla, Dutchman's pipe
  • Bougainvillea species, Bougainvilleas
  • Campsis radicans, Trumpet creeper
  • Clematis montana, Anemone clematis
  • Clematis terniflora, Sweet autumn clematis
  • Ipomoea tricolor, Morning glory
  • Lonicera sempervirens, Trumpet honeysuckle
  • Parthenocissus quinquefolia, Virginia creeper
  • Plumbago auriculata, Cape leadwort
  • Wisteria frutescens, American wisteria

Groundcovers

  • Ajuga reptans, Carpet bugleweed
  • Arctostaphylos uva-ursi, Bearberry
  • Armeria maritima, Sea thrift
  • Bergenia cordifolia, Bergenia
  • Cerastium tomentosum, Snow-in-summer
  • Ceratostigma plumbaginoides, Ceratostigma
  • Epimedium species, Barrenworts
  • Juniperus horizontalis, Creeping juniper
  • Liriope spicata, Lilyturf
  • Pachysandra procumbens, Allegheny spurgePaxistima canbyi, Cliff green
  • Sedum species, Sedums
  • Thymus species, Thymes

Perennials

  • Achillea cultivars, Garden yarrow
  • Agastache foeniculum, Anise hyssop
  • Agastache cultivars, Hyssops
  • Amsonia hubrichtii, Bluestar
  • Anemone species, Anemones
  • Arabis procurrens, A. alpina, Rock cresses
  • Armeria maritima, Sea thrift
  • Asclepias tuberosa, Butterfly weed
  • Aster species, Asters (many species)
  • Baptisia australis, False blue indigo
  • Chrysanthemum cultivars, Chrysanthemums
  • Coreopsis species, Coreopsis
  • Dianthus species, Pinks
  • Diascia rigescens, D. barberae cultivars, Diascias
  • Dicentra chrysantha, Golden eardrops
  • Echinacea purpurea, Purple coneflower
  • Echinops bannaticus, Globe thistle
  • Eryngium bourgatii, Sea holly
  • Euphorbia species, Euphorbias
  • Gaillardia species, Blanket flowers
  • Gaura lindheimeri, Gaura
  • Hemerocallis species, Daylilies
  • Iberis sempervirens, Candytuft
  • Kniphofia cultivars, Torch flowers, red-hot pokers
  • Liatris species, Blazing stars, gayfeathers
  • Lychnis coronaria, Rose campion
  • Nepeta species, Catmints
  • Oenothera species, Evening primroses
  • Origanum laevigatum, Ornamental and culinary oregano cultivars
  • Papaver species, Poppies
  • Penstemon species, Penstemons, beard-tongues
  • Phlox subulata, Woodland phlox
  • Physostegia virginiana, Obedient plant
  • Pulsatilla vulgaris, Pasque flower
  • Rudbeckia species, Black-eyed Susans
  • Salvia species, Sages
  • Sedum species, Sedums
  • Sempervivuns tectorum, Hens and chicks
  • Sisyrnchium angustifolium, Blue-eyed grass
  • Stachys byzantina, Lamb's ear
  • Thymus species, Thymes
  • Verbascum bombyciferum and V. chaixii cultivars, Mulleins
  • Yucca species, Yuccas

Bulbs and Tuberous Plants

  • Agapanthus cultivars, Agapanthus
  • Allium caeruleum, A. sphaerocephalum, and other allium cultivars, Ornamental onions
  • Crocosmia cultivars, Montbretias
  • Fritillaria species, Fritillaries
  • Nectaroscordum siculum, Nectaroscordum
  • Tulbaghia violacea, Society garlic

Annuals

  • Calendula officinalis, Pot marigold
  • Capsicum species, Ornamental peppers
  • Celosia cristata, Cockscomb
  • Eschscholzia californica, California poppy
  • Felicia amelloides, Blue marguerite
  • Gazania rigens, Gazania
  • Helianthus annuus, Sunflower
  • Helichrysum bracteatum, Strawflower
  • Nigella damascena, Love-in-a-mist
  • Papaver cultivars, Annual poppies
  • Salvia species, Annual salvias
  • Zinnia angustifolia, Zinnia

Ornamental Grasses

  • Calamagrostis x acutiflora, Feather reed grass
  • Festuca glauca, Blue fescue
  • Helicotrichon sempervirens, Blue oat grass
  • Panicum virgatum, Switch grass
  • Pennisetum species, Fountain grasses
  • Schizachyrium scoparium, Little bluestem
  • Sorgastrum nutans, Indian grass

Drought Facts

First, a couple of basic questions: What's causing the current drought? With icebergs the size of Rhode Island breaking off Antarctica, one might be tempted to link the drought to human-influenced global warming. But experts say it's premature to characterize what is probably a normal fluctuation in the weather (the short-term state of the atmosphere) as a climatological event (a long-term trend).

The earth's climate, of course, continuously changes without any help from us, cycling through periods of warming and cooling. It has to do with everything from fluctuations in solar activity to shifts in the planet's orbital tilt. In other words, even if you left humanity out of the picture, drought would be a regular occurrence.

What exactly is a drought? Climatologists have a list of different definitions, reflecting the complexity of the phenomenon. Generally speaking, it is a period of less-than-average rainfall. Predicting when a drought will end, or when a new one will begin, is close to impossible.

"Basically each day is a new slate," says Mark Svoboda, a climatologist with the National Drought Mitigation Center, an advisory institution based at the University of Nebraska-Lincoln. "The drought could be over soon, or it could draw out for years."

Svoboda points out that "because drought is so unpredictable and hard to read, and because it is a natural part of our climate cycle, we need to be conserving water at all times, even when it seems to be in abundance."

Ten Short-Term Tips

Here are ten easy ways on how you can conserve water in your garden this summer without harming your plants:

  1. Water your plants early in the morning.
    Mornings are cool, and water doesn't evaporate as readily as it does in the heat of the afternoon. Evenings are cool too, but water sitting on leaves overnight can cause fungal diseases.
  2. Water less frequently but deeply.
    Frequent, shallow waterings lead to weak, shallow-rooted plants. Less frequent, thorough waterings encourage roots to grow deep, where the soil stays moist longer.
  3. Water the soil, not the plants.
    Use a watering can, soaker hoses, drip irrigation, or other water-conserving irrigation techniques that saturate the soil while leaving the foliage dry.
  4. Mulch your plantings.
    A two- to three-inch layer of organic mulch such as shredded leaves or bark or compost slows evaporation by shading the soil, slows water runoff, and as a bonus, enriches the soil as it breaks down.
  5. Don't prune, fertilize, or apply pesticides during a drought emergency.
    All of these would put additional stress on your plants.
  6. Put off major planting projects until water is more plentiful.
    All newly established plants require a lot of irrigation. It's best to delay planting trees, shrubs, and large herbaceous borders until the drought is over.
  7. Choose drought-tolerant plants for pots and for filling in existing plantings.
    Certain characteristics indicate that a plant has low water requirements: Plants with silvery, hairy, or fuzzy leaves (such as woolly thyme, Thymus pseudolanuginosus), succulent leaves (such as rose moss, Portulaca species), or leaves with a waxy coating (such as ivy-leaved geranium, Pelargonium peltatum) are good choices. Plants with long taproots, such as butterfly weed (Asclepias tuberosa), are good choices as well. See "Drought-Tolerant Plants," page 13, for more recommendations.
  8. Improve potting mixes.
    For your container plants, consider incorporating hydrogels into the potting soil. These water-retaining polymers hold several hundred times their weight in water and release it gradually to the plants' roots. Be careful not to add more than the recommended amount—too much of a good thing and your plants will be pushed out of their containers by the expanding crystals. Presoaking hydrogels until they are fully expanded makes them easier to incorporate with the potting soil in the proper ratio.
  9. Cut down on mowing, fertilizing, and watering, and let your lawn go dormant.
    Mowing causes water loss. Mow during the coolest part of the day, and leave the clippings, which return small but valuable amounts of moisture to your lawn. Raise the mowing height, because taller grass shades the soil, reducing water loss; the University of Massachusetts Extension recommends settings of two to three inches. Most turfgrasses are adapted to summer drought. They turn a nice buff brown color as they go dormant, sending their water reserves down to the roots for safekeeping. Given a bare minimum of water, your lawn will green up again in fall when temperatures cool.
  10. Consider collecting and recycling water.
    Depending on where you live, you may be able to connect your downspouts to rain barrels to collect roof runoff. When water used for boiling pasta and vegetables cools, use it to water your plants. Use of other types of "gray water," such as that from showers, baths, washing machines, and dishwashers, is regulated by some municipalities, and the detergents and other chemicals in the water can be harmful to some plants.

Long-Term Solutions

The following additional steps will make your garden much less vulnerable to future droughts as they preserve supplies of fresh water. It's best to save these projects until the current drought is over.

Reduce the size of your lawn. The typical lawn requires regular irrigation and care to maintain its aesthetic appeal. Consider widening your borders and planting beds, and replacing thirsty turfgrass with water-thrifty trees and shrubs. Once established, most trees and shrubs require less water than herbaceous plants. Fill in with drought-tolerant perennials, annuals, bulbs, and groundcovers. See the box below for specific recommendations.

Add organic matter to the soil as you plant. Compost and other organic matter increase the soil's ability to retain moisure.

Switch to low-maintenance grasses in remaining lawn areas. One very attractive alternative is buffalograss (Buchloe dactyloides), a fine-leafed, soft-textured species indigenous to the Great Plains. Because it is adapted to the periodic and prolonged droughts characteristic of that region, it needs minimal water once established and no fertilizer.

Supplier Information

Most good local home-improvement stores and garden centers carry a range of products that can help you conserve water.

Gardener's Supply Company
sells soaker hoses, drip-irrigation systems, root-zone watering devices, rain barrels, water-efficient planters, and hydrogel
128 Intervale Road, Burlington, VT 05401
800-427-3363
www.gardeners.com

M.K. Rittenhouse & Sons
offers many of the same products plus a rain-sensitive sprinkler system
1402 Fourth Avenue, St. Catherines, ON L2R6PQ, Canada
877-488-1914
www.rittenhouse.ca

Janet Marinelli is the former director of Publications at Brooklyn Botanic Garden.

Niall Dunne is a former editor at Brooklyn Botanic Garden.

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