I don’t worry about the pots that need to be watered when I go on a summer vacation. I worry instead about the pots that don’t need to be watered. Last summer I hired a very efficient woman to water the many containers throughout my garden. But there were certain plants I didn’t want her to water, even with the hot, dry conditions we experience in July in Denver. These drought-adapted plants, especially the cacti, like it dry, so I put them on the flattish roof of our covered patio, where they could bake in the full, hot sun and be missed entirely by our enthusiastic waterer.

Plants like cacti, succulents, aloes, and sotols are amazingly tolerant of human forgetfulness; hot, baking sites; and even outright abuse—so they thrive where other potted plants fail. I have many of these plants in pots in my garden, and they demand much less attention than the usual containers of annuals and tropicals. Drought-adapted (also called water-wise, xeric, or low-water) plants also have strikingly different forms, colors, and textures, which add dramatic sculptural beauty to my garden. But most impor­tant, they conserve water resources and save me time spent watering during the hot summer months.

When it comes to choosing pots, I use both glazed ceramic and natural clay pots. The best choices for my water-wise plants are pots that closely match the size of the plant’s root mass and have ample drainage holes. Minimizing the size of the container keeps the soil mass smaller, which helps it dry out more quickly. Most of these plants come from habitats where soil is as scarce as rain, so they are quite happy in tight quarters. It will be obvious when it’s time to upgrade a certain specimen to a larger pot: The plant will outsize its container, becoming top-heavy and out of scale with the pot yet still appearing robust and healthy.

Succulents and cacti are two types of plants suited to dry containers

1. Thompson’s yucca (Yucca thompsoniana, USDA Hardiness Zones 7–11) 
2. Silver jade plant (Crassula arborescens, Zone 11)
3. Devil’s tongue (Ferocactus latispinus, not hardy below Zone 11) 
4. Mammillaria (Mammillaria sp., not hardy below Zone 11) 
5. Bishop’s cap (Astrophytum myriostigma, Zone 11) 
6. Thorncrest century plant (Agave lophantha, Zones 9–11)

I garden in two locations, Colorado and Texas, and use different soil mixes for my drought-adapted plants in each place. In my Denver garden, which has dry summer weather, I use a soilless mix that contains very little peat moss, and I add perlite or pumice gravel to it. My winter garden in central Texas is wetter and more humid, so I add coarse grit or pea gravel to the mix because extra drainage is a must. I will often create my own mix of 50 percent pea gravel and 50 percent compost and pine bark for my Texas pots, although it makes the containers rather heavy. I don’t add moisture-retaining polymer crystals to either of these potting mixes because these plants like it dry. Also, their roots are healthier when the soil is allowed to dry out, which it tends not to do when these moisture retainers are mixed in.

Even though these plants like it dry, they need to be watered and fertilized periodically. It is critical, however, to give them a dry spell between waterings. That dry time can last days or even weeks, with no harm done to the plants. When you do water them, it’s important to be thorough, repeating the process a couple of times to guarantee that the entire soil mass gets wet. For my pots, I apply a liquid fertilizer at half strength about once a month during the growing season at the same time that I water. You could also mix slow-release fertilizer into the soil when you plant the pot or sprinkle some around the base of plants in an established container.

Hot, dry climates are found around the world, and the diversity of forms and drought-survival strategies of the plants that thrive in these hot areas boggles my mind. Most of these plants store water in their leaves, stems, or roots, and although there are many plants waiting to be discovered for garden use, there are lots already available for us to try. A few of these plants are winter hardy, but most are not, so I treat them either as annuals, letting them die at the end of the season, or as tender perennials. As I do with my tender perennials, I bring some of them into the house for the winter, placing them in a sunny spot and watering them infrequently. They never look their best, but they usually make it through to the following spring.

One of the most popular and easy-to-find groups of drought-adapted plants is succulents, which store water in their leaves. This broad group includes the cold-hardy hens and chicks (Sempervivum spp. and cvs., Zones 4–11) and sedums (Sedum spp. and cvs., Zones 3–9) as well as the more tender graptopetalums (Graptopetalum spp., Zones 9–11) and echeverias (Echeveria spp. and cvs., Zones 10–11).

Another easy-to-find group is the large, diverse cactus family, which eschews leaves for succulent stems that hold moisture through dry times. They come in various prickly forms, including barrels, pads, mounds, and clumps. All cacti grow well in containers—just be careful of their spines and of the tiny but more obnoxious glochids, the small clusters of stiff hairs that can get stuck in your skin.

South Africa is home to a host of dry-loving plants, all of which make great container specimens. The ice plant family (Aizoaceae) includes plants like living stones (Lithops spp., Zones 10–11) and hardy ice plants (Delosperma spp. and cvs., Zones 6–11). There are also delightful aloes (Aloe spp. and cvs., Zones 10–11) and their cousins, the gasterias (Gasteria spp., Zones 9–11) and haworthias (Haworthia spp., Zones 9–11), as well as the long-blooming bulbines (Bulbine spp. and cvs., Zone 11). Another South Africa plant family (Crassulaceae) includes crassulas (Crassula spp. and cvs., Zone 11), kalanchoes (Kalanchoe spp. and cvs., Zone 11), and cotyledons (Cotyledon spp., Zone 11), which come in many shapes, sizes, and colors. There are also euphorbias (Euphorbia spp. and cvs., Zones 4–11) that need little water and are perfect for pot culture.

From the desert Southwest of North America are plants like agaves (Agave spp. and cvs., Zones 9–11), yuccas (Yucca spp. and cvs., Zones 4–11) and sotols (Dasylirion spp., Zones 8–11), bear grasses (Nolina spp., Zones 8–11), and ponytail palms (Beaucarnea spp., Zones 11), all of which sport tough, leathery leaves that are sometimes far from succulent yet are adapted to withstand dry conditions. These woody lilies, as they are sometimes called, hold moisture through dry times, and some are also quite cold hardy.

The Americas are also home to a wealth of bromeliads, including puyas (Puya spp., Zones 9–11), hechtias (Hechtia spp., Zones 9–11), and dyckias (Dyckia spp. and cvs., Zones 9–11). With their drought tolerance and their strange and spiny starfish-like appearance, they make delightful container specimens that are worth looking for.

Finally, a plant that can be found in almost every nursery is the floriferous annual moss rose (Portulaca grandiflora cvs.), which is tolerant of heat and drought. Available in a range of hues, it makes a colorful addition to containers with other specimens, playing a supporting role under the larger horticultural stars. Also, in the same fam­ily, the genus Talinum (Zones 6–9) contains several colorful species well adapted to pot life, including jewels of Opar (Talinum paniculatum and cvs., annual), which comes in variegated-leaf and chartreuse forms.

All of these plants perform well during dry periods. This makes them the perfect container plants for busy gardeners or for people like me who can relax on vacation knowing their pots don’t need to be watered.

Your weather determines your soil mix

Dry summers

Use a soilless mix that doesn’t contain much peat moss, and add perlite or pumice gravel to it.

Moist/humid summers

Use a soilless mix, and add coarse grit or pea gravel to it because extra drainage is a must. You can also create your own mix of 50 percent pea gravel and 50 percent compost/pine bark. Be aware, however, that this mix will add a lot of weight to your containers.

Note: Don’t add moisture-retaining polymer crystals to either of these potting mixes, because water misers like it dry.

Frequent Fine Gardening contributor Tom Peace neglects his pots in both Denver and Texas, depending on the season.

Photos, except where noted: Jennifer Brown

Sources

• Bob Smoley’s Gardenworld, Dunnellon, Fla.; 352-465-8254; bobsmoleys.com
• Hight Country Gardens, Santa Fe, N.M.; 800-925-9387; highcountrygardens.com