PLANTS FOR DRY SITES & DROUGHT CONDITIONS

Barbara J. Bromley, Mercer Co. Horticulturist 04

There are several situations when it would be desirable to plant dry site tolerant plants. These situations include: shallow soil, sandy soil, rocky or gravelly soil, irrigation restrictions, unreliable wells, areas of expected low rainfall, large properties too far from a water source, and the simple desire not to have to water plants.

Some plants are adapted to low water conditions. Cacti and sedums are able to store water in succulent stems. Plants like butterfly weed and some oaks have deep root systems. Small leaves (thyme, juniper), waxy leaves (American holly, yucca), and hairy leaves (lamb’s ear, artemesia) are all adaptations that reduce water loss. Summer dormancy in spring flowering bulbs enable those plants to sit out hot dry summer weather as long as rains return eventually.

Very few plants must have dry conditions. Many plants that tolerate dry conditions prefer a moist well-drained location, but will tolerate drought for a short or moderate period. Very few plants will tolerate extended drought over several months during the growing season without some supplementary watering. The plants listed on adjacent pages for New Jersey gardens will tolerate dry soils once they have become established after transplanting and have developed a healthy root system. Selecting plants based on their soil, sun, and water, and other cultural requirements will help alleviate major headaches later in the season.

Cultural practices can increase the drought tolerance of any plant.

  • Improve soil by the incorporation of compost or other organic matter and by tilling to improve aeration and, therefore, root growth.
  • Have a soil test run to determine pH level and limestone and fertilizer needs. Healthy but slightly stressed plants are often more tolerant of difficult environmental conditions. Do not overfertilize. Plants with lush growth are often floppy or intolerant of stress.
  • Use mulches to maintain even soil moisture, reduce evaporation, reduce competition with weeds, and keep soil temperatures even.
  • Select plants for the landscape and gardens that are more likely to tolerate dry conditions, and group them in similar areas. Plan ahead. Transplant recovery from several weeks for annuals to several years for trees is necessary before the plant is actually drought tolerant.
  • When watering is allowed/necessary, water infrequently, but deeply to encourage the roots to search deeper in the soil to find water. Shallow frequent watering or heavy watering stimulates shallow rooting and diminishes drought tolerance.

It is possible to reduce drought tolerance in an otherwise tolerant plant by overfertilizing or by fertilizing at normal rates in a dry year and creating a lush vegetative plant. Deep root systems develop if a plant has to seek water. Watering too heavily or too often diminishes this drought tolerance.

Almost all of the plants that are dry soil tolerant prefer full sun growing conditions. Some will tolerate light or partial shade. Those that tolerate light shade (the brightest shade category) are designated LS in the attached table. Plants in the shade tolerant listing marked with XX prefer shade and/or are sun intolerant.

The plants in the deer resistant list with a single X are known to be somewhat resistant to browsing in some situations, but not under heavy herd pressure. No X entry indicates deer tolerance is unknown. The # symbol designates plants generally fed on by deer.

Where both a genus and species are listed for a plant, there may be other members of the genus that don’t tolerate dry conditions. If spp. follows the genus, generally most or all members are dry site tolerant. Check a reliable reference to determine the growing requirements of both wild and garden plants.

 

HERBACEOUS (non-woody) PERENNIALS

Botanical Name Common Name

Drought tolerance

Shade tolerant

Shore or sandy soil

Deer resistant*

Achillea filipendulina yarrow

X

X

Achillea tomentosa woolly yarrow

XX

X

Achillea ptarmica ‘The Pearl’ Pearl sneezewort

X

X

Aegopodium podagraria bishop’s weed

X

Alyssum saxatile gold dust

X

X

Amsonia tabernaemontana blue-star

X

X

Antennaria rosea pink pussytoes

X

Anthemis tinctoria golden marguerite

X

XX

X

Armeria caespitosa thrift

X

X

X

Armeria maritima sea pink

X

X

X

Artemesia spp. wormwood, silver mound

X

X

Asclepias tuberosa butterfly weed

X

X

X

Aubretia deltoides purple rock cress

X

LS

X

Aurinia saxatile basket of gold

X

Baptisia australis blue false indigo

X

X

X

Baptisia tinctoria wild yellow indigo

X

X

Belamcanda chinensis blackberry lily

X

X

Bergenia spp. leatherleaf bergenia

X

X

X

Boltonia asteroides boltonia

X

LS

X

Callirhoe involucrata low poppy mallow

X

Cassia marilandica wild senna

X

Catananche cerulea Cupid’s dart

X

Centranthus ruber Jupiter’s beard

X

X

Cerastium tomentosum snow-in-summer

X

Ceratostigma plumbaginoides blue plumbago, leadwort

X

Chrysanthemum x superbum Shasta daisy

X

X

Chrysopsis mariana golden aster

X

Cimicifuga racemosa bugbane

XX

X

X

Convallaria majalis lily-of-the-valley

X

XX

X

Coreopsis spp. tickseed

XX

X

Dianthus spp. pinks

XX

X

X

Echinacea purpurea purple coneflower

XX

X

Echinops ritro globe thistle

XX

X

Epimedium spp. barrenwort, Bishop’s hat

X

XX

X

Eryngium spp. sea holly

X

XX

X

Euphorbia spp. cushion spurge

XX

X

X

Gaillardia x grandiflora blanketflower

XX

XX

X

Gaura lindheimeri white gaura

X

Gillenia trifoliata Bowman’s root

XX

XX

Gypsophila paniculata baby’s breath

X

X

X

Gypsophila repens creeping baby’s breath

X

X

X

Hedera helix English ivy

X

XX

#

Helianthemum nummularium sunrose

XX

Helianthus spp. sunflowers

X

#

Hemerocallis fulva tawny daylily

XX

X

#

Hypericum perforatum common St. John’s wort

X

X

Iberis spp. candytuft

X

#

Iris germanica German bearded iris

X

Kniphofia uvaria red hot poker, torch lily

X

X

Lamium galeobdolon yellow archangel

X

XX

X

Lamium maculatum ‘Beacon Silver” spotted dead nettle

X

XX

X

Lathyrus japonicus beach pea

X

XX

Lavandula angustifolia lavender

XX

XX

XX

Limonium latifolium sea lavender, statice

X

LS

XX

X

Liriope muscari lilyturf

XX

X

Lychnis coronaria rose campion

X

X

X

Nepeta x faassenii catmint

X

LS

X

Oenothera spp. sundrops, evening primrose

XX

X

X

Opuntia humifusa prickly pear

XX

XX

XX

Origanum vulgare wild marjoram

X

XX

Papaver orientale Oriental poppy

X

X

X

Parthenocissus quinquefolia Virginia creeper

XX

X

#

Parthenocissus trifoliata Boston ivy

XX

X

#

Penstemon spp. beard tongue

X

X

Perovskia atriplicifolia Russian sage

X

X

Phlox paniculata garden phlox

X

X

X

Polygonatum spp. Solomon’s seal

X

XX

Potentilla spp. cinquefoil

XX

LS

X

Pulmonaria spp. lungwort

X

XX

X

Rudbeckia spp. black eyed Susan

X

LS

X

Ruta graveolens rue

X

X

Salvia spp. salvia, sage

XX

LS

X

X

Santolina chamaecyparissus lavender cotton

XX

X

X

Sedum spp. stonecrop

X

LS

X

X

Solidago spp. goldenrod

X

LS

XX

XX

Stachys byzantina lamb’s ears

X

LS

X

Tanacetum vulgare tansy

X

XX

Teucrium chamaedrys germander

X

X

XX

Thymus spp. thyme

X

X

Verbascum spp. mullein

XX

X

Verbena spp. verbena

XX

LS

X

X

Veronica spicata spike speedwell

X

X

Vinca spp. periwinkle

X

XX

X

Yucca filamentosa Adam’s needle

XX

LS

X

X

ANNUALS

Botanical Name Common Name

Dry or drought tolerant

Shade tolerant

Shore or sandy soils

Deer resistant

Abronia umbellata sand verbena

XX

XX

Ageratum houstonianum ageratum,

X

X

Amaranthus tricolor amaranth, Joseph’s coat

XX

Arctotis grandis arctotis, African daisy

XX

X

X

Begonia semperflorens begonia, wax

X

X

X

Calandrinia umbellata rock purslane

XX

Calendula officinalis calendula, pot marigold

XX

X

XX

Catharanthus rosea Madagascar periwinkle, annual Vinca

XX

X

Celosia argentea cristata crested cockscomb

X

Celosia argentea plumosa feather cockscomb,

X

Centaurea cyanus cornflower

XX

XX

X

Centaurea moschata sweet sultan

X

Cleome hasslerana spider flower

X

X

Convolvulus tricolor morning glory, dwarf

XX

X

X

Coreopsis tinctoria calliopsis, annual coreopsis

XX

X

Cosmos bipinnatus cosmos

XX

X

Cosmos sulphureus cosmos

X

Cynoglossum amabile Chinese forget-me-not

X

Dimorphotheca sinuata Cape marigold

XX

Eschscholzia californica California poppy

XX

X

X

Euphorbia marginata snow-on-the-mountain

XX

X

Gaillardia hyb. blanketflower

XX

XX

X

Gazania longiscapa gazania

XX

Gomphrena globosa globe amaranth

XX

Gypsophila elegans annual babysbreath

X

X

X

Helianthus annuus sunflower, common

X

XX

X

Heliotropum spp. heliotrope

X

XX

X

Iberis spp. candytuft, annual

X

#

Ipomoea spp. morning glory (vine)

X

X

Kochia scoparia triphylla summer cypress, burning bush

XX

Lobularia maritima sweet alyssum

XX

X

X

XX

Mirabilis jalapa four-o’clocks

XX

X

X

Phlox drummondii annual phlox

X

XX

Portulaca grandiflora portulaca, moss rose

XX

X

X

Salvia spp. sage; salvia

X

X

XX

XX

Sanvitalia procumbens creeping zinnia

XX

Senecio cineraria dusty miller

X

X

X

Tagetes spp. marigold

X

X

X

Tithonia rotundifolia tithonia, Mexican sunflower

XX

X

#

Tropaeolium majus nasturtium

X

X

Zaushneria californica California fuchsia

X

Zinnia elegans zinnia

X

X

#

GRASSES

Botanical Name Common Name

Dry or drought tolerant

Shade tolerant

Shore or

sandy soils

Deer resistant

Ammophila breviligulata American beach grass

X

XX

Andropogon gerardii big blue stem

XX

Bouteloua spp. grama grasses

XX

Buchloe dactyloides buffalo reed grass

XX

Elymus arenaria ‘glaucus’ blue lyme grass

XX

LS

XX

Elymus canadensis Canada wild rye

XX

XX

Eragrostis trichoides ‘Bend’ sand love grass

X

LS

XX

Erianthus ravennae hardy pampas grass

X

Festuca elatior tall fescue

XX

X

X

Festuca glauca blue fescue

X

X

Festuca rubra red fescue

XX

X

Koeleria macrantha crested hair grass

XX

Miscanthus sinensis (some varieties) Eulalia grass

X

X

Poa pratensis (common types only, such as S. Dakota certified, Park, or Kenblue ) common Kentucky bluegrass

X

Schizachyrium scoparius little blue stem

X

XX

Sorghastrum nutans Indian grass

X

LS

XX

KEY:   X = tolerant; XX = very tolerant or thrives; LS = light shade only; * resistance unknown on those left blank; # eaten by deer