From the Digest

Leo Chance: Cold-Hardy Picks for St. Louis

Gymnocalycium gibbosum is a reliable bloomer that self-seeds.

By David A. Wolfe (March 2021)
(Click for additional photos.)

In a straightforward and engaging Zoom presentation during the February 2021 HSCSS meeting, retired pro gardener Leo Chance recommended a verbal and visual list of cacti and succulents for growing outside in the sometimes cold and wet conditions of St. Louis.

Several Gymnocalycium species, for example, are rather hardy, bloom consistently and self-seed, too. Moisture-loving Orostachys aggregeatus plants grow readily to form ground cover in cold-hardy gardens. Native to Missouri, Talinum calycinum is a small succulent with purplish flowers that does well in rocky environs. Echinocereus albispinus has attractive white spines, while its brethren develop large, showy flowers. See more suggestions below.

Many of Chance’s recommendations tend to form clusters, from which starts can be readily taken. Chance also grows from seed, with “tons” of plants held under artificial light. He waits a year before transplanting young plants outside, however.

Orostachys spinosa has an attractive shape and color.

Chance said growers can often just cover their plants with frost cloth through the winter months and see them return in the spring. He has found that some species – and individual plants – can survive winter even without cover. “They’re incredibly tough,” Chance said. Remember to remove covers fairly soon after the worst cold subsides, because many of the suggested plants tend to flower early in the year.

Chance said excellent drainage is essential, whether a garden is fairly flat or on a hillside. His garden in Colorado has low berms built up with layers of pumice and non-organic sandy loam. To drain well, flatter terrain may require the use of larger gravel and turface or similar materials. The presentation also showed that large pots and other containers can hold card-hardy gardens, with portability a potential asset.

A bit of advice: “Plants are not good at abruptness,” Chance said. In preparing greenhouse plants for the cold outdoors, lower greenhouse temperatures in steps. And when seasonal covers are removed, note levels of sunlight to avoid overexposing resting plants.

A forest of Yucca thompsoniana and Y. rostrata grows at the Denver Botanic Gardens.

Cold-Hardy Garden Ideas for St. Louis

Aloe aristata
Aloinopsis orpenii, A. spathulata
Cheiridopsis cigarettifera
Echinocereus albispinus, E. bailey, E. coccineus, E. reichenbachii var. perbellus, E. triglochidiatus
Escobaria sneedii, E. vivipara
Euphorbia claveroides var. truncata
Gymnocalycium andreae, G. baldianum, G. bruchii, G. calochlorum, G. gibbosum
Hesperaloe parviflora
Jovibara arenaria
Khadia alticola
Lewisia longipetala
Lithops salicola
Maihuenia poeppigii
Maihueniopsis darwinii
Opuntia strigil
Orostachys aggregeatus, O. fimbriata, O iwarenge, O. minuta, O. spinosa
Rabiea albipuncta
Rebutia densipectinata, R. pygmaea
Ruschia pulvinaris
Sempervivum arachnoideum
Stomatium mustellinum
Talinum calycinum
Titanopsis calcarea
Yucca rostrate, Y. thompsonianas