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