Selecting and growing heat- and drought-tolerant plants is important for many folks living in the warmest and driest parts of the United States. Knowing which vegetables to plant is not always an easy task, but certain varieties will thrive under dry, hot conditions. Of course, there are other factors to consider as well: soil, sun and wind exposure, availability of irrigation water, and more.
Plants that are heat tolerant are not necessarily drought tolerant — and vice versa. And more than just water availability is generally involved with a plant’s ability to cope with heat. For example, adequate soil oxygenation, wind exposure and heat-reflecting properties of soil surfaces and surroundings can all dramatically affect a plant’s ability to tolerate heat, even when you can supply all the moisture it needs. Use this guide to help you choose the healthiest and best-producing plants for even the hottest dry-climate regions.
Peppers, sweet or hot, Capsicum species
Peppers need no description, as there are many species and cultivars commonly grown for their edible fruits. All need a long, warm growing season in order for the fruit to properly ripen. They love heat and prefer a well-drained yet moisture-retentive soil for best results.
Peppers are an excellent source of vitamin A and one of the best vegetable sources of vitamin C. They also contain many other nutrients in lesser amounts.
Tomatillos, Physalis ixocarpa
Grown in much the same way as tomatoes, this interesting perennial vegetable is easily grown as an annual. Growing 3 to 4 feet tall, like many tomatoes, it may need to be trained on a trellis. It bears purple-blotched yellow flowers, followed by golf-ball-sized, purplish fruits that are enclosed in a papery, often purple, veined husk. Try tomatillos for a mildly hot green sauce with tacos, or add raw to salads, pies and jams.
Amaranth, Amaranthus species and cultivars
Amaranth is usually thought of as a grain crop, but many amaranth species and cultivars can also be eaten as vegetables. Young leaves and shoots can be used in salads, and mature leaves can be cooked like spinach. Amaranth is one of only a few greens that enjoy the heat of summer. Most amaranth species prefer warm conditions with full sun for best growth, along with adequate moisture and well-drained, moderately fertile soil.
Amaranth leaves are generally rich in vitamins A, C and K, folate, and minerals such as calcium, iron, magnesium, manganese and potassium.
One species, A. tricolor, known as vegetable amaranth, thrives in hot, dry weather. Its leaves have a distinctive bittersweet flavor. Of the several varieties, most grow about 18 inches tall. Pick leaves as you need them. Another, Amaranthus dubius, known as wild spinach in some regions, has spikes of green and white flowers, oval green leaves, and grows 2 to 3 feet tall.
Globe artichoke, Cynara scolymus
This unique clump-forming perennial can be treated as an annual in colder regions. It grows 4 to 6 feet tall. The plants normally require two full seasons to produce the edible buds, but varieties have been developed specifically to be treated as annuals. These plants enjoy heat and tolerate drought well with moisture-retaining garden mulch and sufficient watering.
Globe artichokes have deeply lobed, hairy leaves that are a gray-greenish above, and densely woolly and whitish beneath. The purple flowers are quite large, up to 6 inches across with large green bracts. These fully develop in late summer to early autumn. You do not want the flowers to open, as it is the plump, unopened flower head buds that are eaten. When firm, tight and a uniform green color, these buds are cut off the plant with a knife in spring or summer.
Once harvested, soak the large globular flower buds in salted water for a couple of hours, rinse, boil until tender, and serve with butter. Scrape off the fleshy part of the scales and solid hearts with your teeth.
Melons, Cucumis melo
Often thought of as fruits, melons are often categorized with vegetables in books and catalogs. These fruits include muskmelons, cantaloupes, crenshaw and honeydew, with many cultivars and varieties.
Melons need a long, sunny, warm season. They prefer well-drained soil with added organic matter and shelter from winds. Many melons do better with a trellis. Keep fruits off the ground if possible.
Melons are a good source of vitamins B2 and C. Cantaloupes are higher in vitamin A than other melons and are also rich in vitamin C and potassium. Honeydew has the highest average sugar content and is rich in vitamin C.
Jerusalem artichoke, Helianthus tuberosus
Jerusalem artichoke is a vigorous perennial with sunflower yellow flowers in autumn, and thick, coarse, hairy stems and leaves. It can spread rapidly and may grow up to 12 feet tall. It produces potatolike tubers that are edible both raw and cooked — baked, boiled, creamed or grated into salads. They are said to be up to five times more productive than potatoes and contain little digestible starch. These plants are propagated from the tubers and not from seed. If the weather is particularly dry in early fall, give your plants a thorough watering to increase tuber size.
Jerusalem artichoke is rich in iron and potassium, and its principle storage carbohydrate, inulin, is not readily digestible, so it has little effect on blood sugar levels. The plant can sometimes be so prolific as to become invasive, but if handled with care, you can achieve a rewarding, controlled crop.
Sweet potato, Ipomoea batatas
Sweet potato is a perennial climber that is closely related to morning glory. It has somewhat fleshy, reddish-purple stems, three-lobed leaves and trumpet-shaped lavender-purple flowers in summer. The edible tubers appear somewhat like large, contorted potatoes, typically with orange flesh. These are deliciously sweet and very nutritious. While regular potatoes grow best in cooler soil, sweet potatoes like it hot.
Sweet potatoes are rich in vitamin A, fiber, carbohydrates and, of course, starch, as well as beta carotene and several other nutrients.
Yardlong or dow gauk beans, Vigna unguiculata sesquipedalis
This heat- and drought-tolerant bean is unlike most others. The pods are long, up to 2 or 3 feet, with 10 to 20 seeds in each pod. Plants need a sturdy trellis. There are several varieties to choose from, including those with purple pods and black seeds.
Pod flavor is similar to the sweet bean. Treated as a green bean, dow gauks are great stir-fried, but feel free to experiment with other preparations. In regions with temperatures too high for a snap bean to thrive, yardlongs are a viable option, though you may need to water regularly as the plants become established.
Okra, Abelmoschus esculentus
Okra performs best with a long, warm growing season, well-drained soil with added organic matter and dry conditions. It is considerably more drought tolerant than most vegetables. The species can grow to 6 feet tall or more. Okra has pale yellow flowers with a red or maroon central area. The flowers, flower buds and pods are edible. The pods can be added to soups or stews, or on their own, grilled, boiled, dipped in batter or breaded and fried.
The younger pods are best for flavor and tenderness. There are many varieties to choose from.
Okra is a great source of fiber, plus many minerals and vitamins. It is particularly high in vitamins C and K, folate, magnesium and manganese.
Edible burdock, Arctium lappa
Not often thought of as a vegetable, burdock is a 2- to 6-foot-tall biennial that can spread rapidly. It has hollow stems, broad heart-shaped leaves and thistlelike flowers that are usually purple. The roots are peeled, sliced and cooked, and have a strong flavor resembling oysters or salsify. It is rich in vitamin C and iron.
Horned cucumber, Cucumis metuliferus
An uncommon cucumber indeed! This annual vine has somewhat rough, hairy leaves and stems, and fascinating spiny, bright orange, 4-inch-long edible fruits. The fruits are bright green on the inside with an almost jellylike texture. The flavor has been described as a combination of banana, lime and cucumber.
Eggplant, Solanum melongena
This tomato relative thrives under low-humidity conditions and prefers soil that is far from saturated with moisture. Eggplant bears pale blue or deep purple flowers, and the stems often have spines. The fruits are usually a dark purple to almost black and somewhat egg shaped, although there are many varieties with highly varying fruit colors and shapes. You can also find eggplant with pink, green, white, yellow, tiny egg sized, round, elongated and oval fruits, to name a few.
Eggplant is rich in fiber, vitamin B2, folate, potassium and manganese, plus several other nutrients.
Malabar spinach, Basella alba and B. rubra
These fast-growing perennial vines are treated as annuals in colder regions. They grow about 12 feet high with abundant bright and glossy, large and thick, heart-shaped leaves. Flowers are white for B. alba and red for B. rubra. Both prefer well-drained soil with added organic matter, thrive in hot weather, and make a great substitute for spinach.
Malabar spinach is rich in vitamins A and C, folate, iron, calcium, magnesium and manganese.
Summer and winter squash, Cucurbita pepo and other Cucurbita species
All squashes are heat- and drought-tolerant. Production and growth is higher in hot areas. They prefer well-drained soil with added organic matter. Both types of squash are high in vitamins A and C.
Watermelon, Citrullus lanatus
Watermelon has the same cultural requirements as melons. They need a long, hot summer and a fairly rich, well-drained soil. Because watermelons are heavy feeders, it helps to prepare your patch by adding seaweed, compost, or aged manure.
Jesse Vernon Trail is an author, curriculum developer and instructor on a number of topics, and encourages and promotes water-wise plants and landscaping.
Here are a few tips to help your treasured but not heat- or drought-tolerant plants cope with extreme temperatures.
- Apply a moisture-retentive mulch layer.
- Adhere to a proper watering schedule for each type of plant.
- Provide protection from wind.
- For certain plants, consider shade cloth to diminish the sun’s impact.
- Provide well-drained yet moisture-retentive soil with added organic matter for nutrient availability.