The Good, the Bad and the Ugly – Surviving St. Louis Winters in a Cold-Hardy Garden

By Jolie Krupnik (March 2015)

Last spring and summer, I devoted my time to planting cold-hardy cacti, purchased mostly from Leo Chance during his visit to our club in May 2014. St. Louis’ latest winter brought many single-digit nights, sleet and snow, but our total amount of precipitation was less than normal.

Wet and cold, I knew, can result in certain death for some cacti. I had greater hopes for plant survival knowing that less moisture would help to preserve the plants’ roots. The first signs of warmer weather in early March had me racing outdoors. What survived, I wanted to know.

I have two cold-hardy gardens. My main garden faces south and sits on a steep slope in front of a fence that shields the north winds. All other sides are open, with full sun all day. The smaller garden is on flat terrain and sheltered from westerly winds on the east side of the house.

At first glance in the main garden, only the dead leaves I had piled on as mulch were visible. After brushing these away, the view looked positive. While there were some losses, most of the plants had survived in both gardens.

The Good

Healthy-looking survivors included the Echinocereus reichenbachi ssp. Albispinus, Echinocereus triglochidiatus “spineless claret cup cactus” and Echinocereus viridiflora. The dense spines on the E. reichenbachi were a creamy white, and a pup, visible last fall, had grown. A new small pup had also sprouted.

The large rock behind it had been strategically placed to divert excess rainfall and block winds. Positioning rocks was a common strategy I used for protecting the plants from water and wind. Rocks, though, can also be used to give moisture to plants. In Cacti and Succulents for Cold Climates, Leo Chance said, “Plants also thrive next to a partially buried larger rock, which allows their roots to take advantage of moisture raining off the rock.”

E. triglochidiatus showed some brown spots around its areoles, on which critters seemed to enjoy nibbling last summer. Nevertheless, I was pleased to see the plump green clumps. E. viridiflora was also plump and green.

An echinocereus (unknown species) and Agave parryi showed very little damage. Both are located in the smaller garden, which is more sheltered but has less sun in the afternoon and very little sun in the winter. The soil is very rocky. The A. parryi measures 3 to 4 inches across – not yet the size of the mature specimens that Missouri Botanical Garden donated to members last year after a frigid winter killed off many of its A. parryi – but hardy nonetheless.

In the main garden, I built a small berm, then planted Cylindropuntia whipplei on top of the berm, placing the bottom of the plant on top of and between two slabs of limestone. I then filled in the space around the roots with gravel. Continuing with the vertical slab theme, like a Susan Amoy bonsai tufa, I added additional slabs that were solely decorative. The slabs separated over the winter, so at some point, I will need to readjust them.

The Bad

The genus Astrophytum is one of my favorites. I was excited after reading in Chance’s book that Astrophytum capricorne is one of the hardier plants that can survive a cold winter outdoors. I had purchased a beautiful, mature A. capricorne from Tom Degnan at last year’s Show and Sale, and when I told him about the plant’s cold hardiness, he donated another healthy, mature A. capricorne that I could plant in my cold-hardy garden.

During one of the club’s September picnics at Drummond Nursery, Gladys Drummond told me that a plant’s roots need to be established in the ground for several months before enduring a cold and wet winter, so I planted the A. capricorne in the ground in the spring of 2014. The plant bloomed outdoors several times throughout the summer.

I feared losing the plant over the winter and missed the beautiful yellow flowers that it had produced multiple times during the summer. Well, I am sorry to report these fears were realized; the A. capricorne did not survive. It may be that the ice and snow did it in, perhaps not enough sun. But I plan to plant A. capricorne again, this time in the sunnier location. I may construct a cold frame for it, as well.

The Ugly

I took a risk planting Echinocereus pectinatus v. rubrispinus in the cold-hardy garden. While E. pectinatus is listed in Chance’s cold-hardy book, the rubrispinus variety is not. I started to notice deterioration early in the winter.

It is normal for these plants to shrivel, but not fold over or hollow out inside. I do not know what caused the hole at the top of mine. This variant may be only cold hardy to 20 degrees and cannot tolerate cold and wet. In hindsight, I probably should not have placed the rock in front of the cacti, which may have trapped water and rotted the roots.

I also planted sedums and succulents. The sedums are very hardy. They wither to nothing in the winter but rebound and bloom in the spring, creating a lovely field of color.

Ann Lapides, owner of Sugarcreek Gardens Nursery in Kirkwood, donated several cold-hardy succulents for planting. She said her nursery had difficulty keeping some of these plants alive. I divided and shared Othonna capensis, Orostachys malacophyllus and Orostachys iwarenge with Mike Hellman, who reported that all survived in his garden. Mine survived, too. The rosularias – R. muratdaghensis and R. serpentinica – were popular critter food, and I couldn’t find the plants or the tags.

Note to self: Draw diagrams of gardens, then identify plant names and locations on the diagram. Store diagram indoors. Many of my outdoor tags were broken or missing, probably due to the number of deer, chipmunks, rabbits and squirrels that tromp (and chomp) through the garden.

There are other members who grow cold-hardy gardens. I hope they will share their experiences and pictures in the Digest. We can all learn from each other.