Drought tolerance of any individual plant can vary from one region to the next so be sure to check your local extension service or local garden centers to see how a specific plant holds up in your region. To be highly drought tolerant a plant needs to be in what it considers to be ideal conditions. If the plant is not well suited to the sun, soil or site, then it may not be as healthy as possible. If the plant is not in good health and growing vigorously, it will not hold up well in dry conditions.
REQUIREMENTS OF A DROUGHT TOLERANT PLANT
Drought tolerant plants are usually quite insistent on well drained soil. Heavy soil that retains water will kill a drought tolerant plant. Loose soil allows the roots to spread and go deep. Some organic matter in the soil helps to retain moisture in loose sandy soils. When establishing a new drought tolerant plant it is very important to water deeply to encourage the roots to go deep to be most effective. Mulch drought tolerant plants with shredded bark to reflect heat and help the soil to retain moisture. And never over fertilize a drought tolerant plant, as a matter of fact most prefer little or no fertilizer at all. Encouraging the plant to develop more blooms and foliage than it is meant to handle on its own will require more water, defeating the whole purpose of planting a drought tolerant perennial.
These are the truly drought tolerant perennials, the ones that are going to make it through the heat of summer in places that you cant reach with a hose. Of course you can’t ignore them completely, these aren’t desert plants. In prolonged periods of drought you need to get out there with a watering can. Most drought tolerant plants would like at least a little drink each week. And in the Midwest you also need to remember that planting areas along the street and even driveway may be high in salt and chemicals from snow plows. Be sure to select salt tolerant plants for these areas. But, these are tough and the most drought tolerant you will find. You may also have noticed that these same plants are on just about every list of low maintenance perennials. Drought tolerance and maintenance often go hand in hand.
THE MOST DROUGHT TOLERANT PERENNIALS:
Gaillardia Blanket Flower is a tough prairie plant that blooms all season until frost. The sunny bloom colors are bright reds and yellows. Full Sun, well drained average soil, very drought tolerant and salt tolerant..
Heliopsis helianthoides False Sunflower are naturals for a dry garden. They are native to dry prairie and spread quite readily. Blooms mid summer into fall. Full Sun.
Achillea Yarrow puts up with heat and drought. Flat clusters of colorful blooms spring into summer. Full sun and well drained soil with low fertility. Salt resistant.
Agastache Hyssop is a southwestern native but it will do well in cold climates, especially drier regions up to zone 5. Tall spikes of tiny blue flowers from midsummer til fall, deadhead to encourage more blooming. Full sun.
Sedum Stonecrop has dense succulent foliage with a wide variety of form. Dense flowerheads bloom from midsummer into fall. Very drought tolerant in well drained soil, does not like fertile soil. Full sun, moderately salt tolerant.
Perovskia Russian Sage tolerates heat and drought, and loves poor soil. The shrubby form with silvery blue flower spikes is a staple in roadside gardens. Full sun to light shade.
Lavendula Lavender is native to the mountains of the Mediterranean where it grows in rocky soils. It is very adaptable and very heat and drought tolerant. Full sun, well drained dry soil.
Echinops Globe Thistle is native to the Mediterranean and reseeds readily in ideal conditions. Globe Thistle produces large steel blue globes of blooms with gray green foliage. Full Sun.
Eryngium Sea Holly is also native to the Mediterranean, producing steel blue spiky looking flower heads.. It grows easily in dry sandy soil in full sun and is very tolerant of poor soil. It will become leggy and sprawl in fertile soil or part shade, and does not like to be over watered. This is an ideal plant for low maintenance gardens on a difficult site.
Echinacea purpurea, the original Purple Coneflower species plant, is the hardiest, toughest, most heat and drought tolerant of the Echinacea. Although it will tolerate some clay and low fertility, it does prefer a good organic soil that is well drained.
Coreopsis verticillatea Threadleaf Coreopsis is a Southern native that is very drought tolerant. They bloom like crazy in summer. The prefer average to sandy soil, full sun to very light shade, and little or no fertilizer.
Rudbeckia hirta Black-eyed Susan is actually a biennial or reseeding annual if you prefer. In any case it is a great drought tolerant plant that blooms profusely in late summer.
Sempervivum tectorum Hen & Chicks are succulents that spread to a groundcover with wonderful color and texture. Full sun to light shade in well drained soil.
Phlox subulata Creeping Phlox brightens any garden in late spring with a blanket of solid bright blooms. It prefers a fertile soil, well drained, in full sun.
Gaura is a delicate looking plant with blooms that float above the foliage. They hold up very well in heat, drought and poor soil, but they will bloom better with regular water.
Pulminarius x allwoodii Dianthus Allwood are drought tolerant as well as salt tolerant. Some of them do prefer regular watering but will put up with long dry spells quite well.
Hemerocallis the species daylily is a very tough and drought tolerant perennial. It is somewhat tolerant of poor soil, is moderately salt tolerant and likes full sun to part shade.
Hemerocallis Daylily ‘Stella de Oro’ produces golden lilies in late summer. It is somewhat tolerant of poor soil and is moderately salt tolerant.
Cerastium tomentosum Snow in Summer is an excellent ground cover perennial for dry sandy soil in full sun. Quite tolerant of poor and even rocky soil. In late spring the gray green foliage is covered with clusters of white blooms. This is a rather short lived perennial but perpetuates by self seeding and spreading runner plants.
Rosmarinus officinalis Rosemary is an annual herb, unless you live in zone 7 or warmer. Rosemary likes full sun and dry conditions and never likes wet soil. The spikey leaves are such a delicious and fragrant herb I have always harvested before it can flower. In mid Atlantic regions or the south the growing season is long enough to see it flower if not consistently harvested.
Thyme should not be limited to the herb garden, it is a lovely drought tolerant ground cover that also blooms. Or for a groundcover, Thymus praecos is also very drought tolerant and blooms like a carpet in spring.
Salvia officinalis Sage is a garden herb that loves sandy soil and average to dry conditions in full sun. Even if you don’t grow sage to use as an herb, there are some very showy cultivars that can add foliage interest to a drought tolerant garden.
Spring blooming bulbs of course are drought tolerant because they go dormant for summer and will start the blooming off in your gardens with a stunning display. And of course there are annuals that are drought tolerant. A few annuals in your garden will ensure blooms from spring to fall. Try zinnia, verbena, annual coreopsis, marigold and cosmos.