(An abridged version of this ran in the Wall Street Journal, 3/9/18.)
Is it a given that Northerners can’t grow succulents? Not at all. Granted, most of these moisture-storing, arid-climate plants prefer warm, sunny habitats. Yet in response to demand, major growers are cultivating tough, showy varieties that sail through subzero winters. The two main kinds are stonecrops and hens-and-chicks, but there exist others that may surprise and delight you.
Snow heightens the color of hens-and-chicks. (Sempervivum globiferum ‘Connie’.) Photo: Mountain Crest Gardens
Stonecrops
Golden barrel cactus is cold hardy only to 14 degrees F. The fluffy ‘Angelina’ stonecrop surrounding it will go well below zero.
Tiny-leaved ground covers like ‘Angelina’, commonly known as stonecrops, spread “even in Zone 3,” notes Panayoti Kelaidis, senior curator of the Denver Botanic Gardens. “They’ll root from little pieces. There are hundreds of different kinds, and they’re the backbone of green roofs.”
Kelaidis says that clump-forming succulents once classified as Sedum (now in the genus Hylotelephium) are “probably the most important succulents for perennial gardens” because of their size and year-round beauty. These shrubs, which unlike true sedums form tap roots and have rosy flowers rather than yellow, have similar star-shaped flower clusters. Although the top growth of hylotelephiums dies and turns brown in winter, “don’t cut them back until spring,” Kelaidis advises. “The dry flower stalks look great covered with snow.”
Plant breeder Brent Horvath of Intrinsic Perennial Gardens in Hebron, IL is perhaps best known for upright sedums with serrated chartreuse leaves and flowers that blanket the plants with clouds of pink. Horvath authored “The Plant Lover’s Guide to Sedums” (Timber Press, 2014).
In his book, Horvath says of the best-known perennial sedum, Autumn Joy (Hylotelephium ‘Herbstfreude’), “The flower heads of soft raspberry pink deepen to garnet as fall approaches. What’s more, in all but the harshest climates, this tenacious plant continues to delight through the winter months as its flower heads turn copper, then bronze.” Monrovia nursery notes, “This sturdy perennial is as tough as they come. Clumping foliage displays large, plate-like flower clusters… Succulent foliage will die back to the ground in cold winter regions, but will re-emerge in early spring.”
Hens-and-chicks
Succulent hens-and-chicks, so called because offsets ring the mother rosette, are in the genus Sempervivum, meaning “ever-living.” “They look best after a snowy winter,” says Matts Jopson of Mountain Crest Gardens near Mt. Shasta in Northern CA. “When sun melted 18 inches of snow that hid the plants for six weeks, “the colors were the most spectacular we’d seen.”
One of very few nurseries specializing in hardy succulents, Mountain Crest Gardens’ “rapid growth has continued through 2017, and we’ve been expanding our selections like never before,” Jopson says. “We should have at least 200 different hardy varieties for sale this spring, at least 50 of which we consider to be rare collectibles.”
Nearly all of the succulents found in the nursery’s Hardy Succulent category can be grown outdoors year-round in zone 5 (-20F) areas such as New York, Boston, and Chicago. “We created that category and our own definition of “hardy” exactly for this purpose,” Jopson says, “to let the large northern population of the U.S. (and thus most of the country’s population) know that they can grow a wide selection of beautiful succulents outside through the winter. Even people in colder Minneapolis should be fine keeping many of the Sempervivum heuffelii and hardy Sedum outdoors.”
Several Sempervivum cultivars by Kevin Vaughn
Jopson says Mountain Crest Gardens works with a hybridizer and creator of “many beloved semp cultivars:” Kevin Vaughn of Salem, OR. Vaughn holds a hybridizing clinic each year in April “organized by the avid semp community on the garden.org forums.” Jopson adds that the breeder’s current goal is to hybridize “a ‘football sized’ semp with the dark color tones of an Aeonium ‘Black Rose’.”
Hybridizer Kevin Vaughn’s book. Release date: May, 2018.
Vaughn’s book, Sempervivum: A Gardener’s Perspective of the Not-So-Humble Hens-and-Chicks, is now available from Amazon.
Among professional breeders of cold-hardy succulents mentioned by both Jopson and Kelaidis is Chris Hansen of Michigan-based Garden Solutions (chris@sunsparklersedums.com). Hansen says of one of his cultivars, Sempervivum ‘Gold Nugget’, “It’s a once-in-a-lifetime plant, the world’s first bright yellow semp with red tips.” Depending on location and growing conditions, ‘Gold Nugget’ turns shades of lime green and hot pink in summer, gold and red in spring and fall, and warm red in winter.
Chris Hansen shows Sempervivum ‘Gold Nugget’, part of his registered Chick Charms line of hens-and-chicks.
See more of Hansen’s patented plants, including his SunSparker Sedums, on my Thirty Cold Hardy Succulents for Northern Climates page. His online mail-order plant business (with Mary Walters) is www.GreatGardenPlants.com.
Sempervivums are monocarpic, meaning that after a rosette blooms, it dies. But this seldom compromises a colony’s appearance. Chicks carry on, filling gaps with their own offsets in spring.
Ice plants
Delosperma ‘Fire Spinner’ is a Kelaidis introduction
Naturally Kelaidis mentions ice plants, of which he says tongue-in-cheek, “I invented 35 years ago.” He trekked through Siberia, Mongolia, and similarly remote, high-elevation regions seeking mat-forming succulents with shimmering, daisylike blooms. Kelaidis went on to introduce many—including his own hybrids—to gardens in the Rockies and beyond.
Asked to name an ice plant that’s especially floriferous, Kelaidis praises purple Delosperma cooperi: “It blooms all summer.”
How to Grow Hardies
There’s more to growing hardy succulents than plunking them in the ground. They need to be acclimated to the cold, Jopson advises. “It’s never a good idea to leave them outside in a hard freeze immediately after delivery. Established root systems are required for most hardy succulents to survive the coldest winter temps, and it is recommend to plant in the ground, beds, or large containers for additional insulation for the roots. Snow is actually welcomed by hardy varieties as it can insulate them from frigid air temperatures. Many of our semps and hardy sedum spent over a month buried in 18 inches of snow last year, resulting in tremendously vivid red, pink, purple, and even some orange tones later in the spring. (Most eventually settle into greener tones by the end of summer.) They also survived a record -15 F night without issue.”
“Wetness is the enemy,” cautions Kelaidis. “Plant them in walls, rock gardens and shallow containers.” Give in-ground plants maximum sun exposure and “a microclimate similar to a Russian steppe:” a south-facing slope amended with coarse, gritty soil.
RELATED INFO
On this site:
How to Grow Tender Succulents in Northerly Climates. Nearly any succulent will grow in northern climates as a windowsill or greenhouse plant. Your biggest challenge is giving these sunbathers enough light. Indoors, set them near [Continue reading]
In print:
Designing with Succulents (2nd ed.) See the section on Cold-Climate Succulent Gardens.
All my books show design ideas and give care and cultivation for Sedum and Sempervivum.
Sempervivum: A Gardener’s Perspective of the Not-So-Humble Hens-and-Chicks, by Kevin Vaughn
On my YouTube channel:
— Growing Succulents in Northerly Climates, Sempervivums Gorgeous new cultivars and design ideas from my presentation at the Northwest Flower & Garden Show.
— Growing Succulents in Northerly Climates: Sedums and More More cool succulents for cold climates plus how to select, grow and design using them. From my second presentation at the Northwest Flower & Garden Show.
— Sedum Chicks at the Northwest Flower & Garden Show. Designer/grower Becky Sell of Turner, Oregon explains how to beautifully combine sedums, sempervivums and other cold-hardy succulents.
— Make a Frost-Hardy Succulent Wreath with Hens-and-Chicks. Simple steps to a stunning wreath!
https://mountaincrestgardens.com/hardy-succulents/
https://mountaincrestgardens.com/sempervivum-hens-and-chicks/
https://mountaincrestgardens.com/sempervivum-heuffelii/
https://mountaincrestgardens.com/sedum-stonecrop/
https://mountaincrestgardens.com/waterwise-botanicals-opuntia-cactus/
https://mountaincrestgardens.com/succulent-care/#hardy-vs-soft
https://mountaincrestgardens.com/succulent-care/#planting-care
View my abridged article in The Wall Street Journal, Mar. 9, 2018.
The post Showy Succulents for Snowy Climates (Debra’s WSJ Article) appeared first on Succulents and Succulent Garden Design | Debra Lee Baldwin.
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