But they must be planted in fall, not spring.
Spring-planted perennials will need watering. They don't have enough roots to collect enough water to withstand droughts. The fall-planted perennials on my top-10 list can handle the drought.
Top 10 Drought-busters
To keep this short and sweet, here are the top 10 plants you can buy with complete confidence. You may plant them this spring if and only if you promise to water them the entire summer. Next year they will fend for themselves without much care.
1. Salvia guaranitica. Tough and durable, it blooms from May to November and attracts hummingbirds and butterflies. It grows a thick storage root and persists even with tilling. It prefers full sun. Trimming in midsummer, after the first flowers are spent, yields a glorious fall display. It will wilt in summer heat when dry but returns with a vengeance when it rains.
2. Sedum spectabile 'Autumn Joy.' When most sedums go dormant, this one grows into well-behaved mounds of blue-green foliage and large clusters of pink flowers with zero watering all summer. Few pests and almost no diseases affect it. Plants can be divided every four years or so in early spring.
3. Clematis paniculata. Deer hate it. Drought can't kill it. This aggressive vine spreads 10-12 feet in a season, blooms in late August and is incredibly easy to establish. A pleasant green vine, its late-summer flowers hide the vine. Cut to a foot high, it will spring back each year as if nothing happened.
4. Belamcanda chinensis. The blackberry lily does well at the edges of Georgia woods without watering. It prefers highly organic soils and full sun. It's drought-tolerant, tough and reseeds well. Planted in dense groups, it's beautiful by midsummer. With care, it has few pests. Deer ignore it, but butterflies love the flowers.
5. Kniphofia uvaria (Tritoma). Drought can't kill this late spring-blooming plant once it's established. Deer leave it alone, too. Properly named Red Hot Poker, it's showy and tough as nails, but has to be established in the fall. Buy grown plants in bloom, known divisions or tissue-cultured plants (seedling color and flower shape can vary dramatically).
6. Delosperma cooperii. The hardy ice plant is an asset on poor soils, dry sites and slopes, requiring only a few inches of soil. It blooms early in spring and then sporadically all summer. Fertilize in June and August, and don't worry when frost kills it back. The tiny, gray, stem-end leaves will burst forth in spring.
7. Helianthus angustifolius. The swamp sunflower is huge, with flower stalks 8 feet tall. But it will stay small (4 to 5 feet) when neglected, surviving the worst drought and hottest summer you can imagine in Georgia. The flowers are spectacular in August and September, and the plant has few pests or diseases.
8. Ruellia brittoniana. The Mexican petunia is a tall, late-blooming, long-lived and spreading perennial. Divide it every five years and enjoy the purple or pink flowers in August and September. Almost pest-free, it has few diseases. It will wilt in the worst drought, but comes back every time it rains.
9. Narcissus hybrids. Gardeners seem to resist including bulbs in discussions of perennials, but indeed they are fantastically adapted perennials. They disappear when things get hot and then return to bloom in spring. Choose from hundreds of cultivars. No matter how bad the drought, daffodils survive.
10. Lantana camara 'Miss Huff.' This is the only truly hardy perennial lantana. It tolerates heat, drought and cold, wet soils. Miss Huff grows into a 6- to 8-foot mound in good soil, with thousands of swallowtail-attracting flower clusters all summer. Planting on 36-to 48-inch centers is essential.
(Paul Thomas is a horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.)