Gardenwise: The Season (and Reason) for Sedums
by Susan Tito
As summer’s sultry days wind down and the promise of fall’s cooler temperatures beckon, I use this transitional time between seasons to take inventory of my plants and evaluate their performance in the garden.
What I’ve noticed is that summer stalwarts like daylilies, bee balm and iris are past their prime. At the same time, autumn beauties like New England asters, Japanese anemone and Montauk daisies are vibrant and on the verge of bursting into bloom — but just not yet.
And then there are my sedums.
I’ve been growing several species of sedum — commonly known as stonecrop — for years, but it is only recently that I’ve acquired a newfound appreciation for them. They may not have the showiest blooms or sweetest fragrance in the plant kingdom, but sedums are among the few perennials on my property that are truly spectacular this time of year.
Their beauty is only one reason to consider this plant; here are some others:
“Sedums are tough, easy to propagate and have so much variety,” said Brent Horvath, owner of Intrinsic Perennial Gardens, a wholesale nursery in Hebron, Illinois. Mr. Horvath, who regularly introduces sedums into the trade, holds a dozen plant patents, including several for sedums.
Mr. Horvath is such a fan of the plant that he penned The Plant Lover’s Guide to Sedums (Timber Press, 2014).
“Most of the new sedums come into cultivation very deliberately by breeders like me,” he said. “Whether in sun or part shade, container or garden, tall or short, and in almost every color — there is a sedum that will work.”
That’s good news for Long Island gardeners, as many sedums are well suited to our zone 7 climate.
“There are hundreds of varieties and many species of sedums in the world. Most are from the Northern Hemisphere, where the nights are cooler than the days,” said Elaine Peterson, who is on the board of the Horticultural Alliance of the Hamptons and grows several sedum varieties in her Montauk garden. “Most started as coastal plants, so many are well adapted to our area and hardy here.”
Sedums shine in the mixed border or rock gardens, and are a magnet for honeybees. They work well as an accent plant, adeptly fill in blank spots in the landscape, and are equally versatile as a groundcover, depending on the species.
Perhaps one of sedums’ greatest attributes is their fleshy, succulent foliage, which makes them drought tolerant — a boon to those who embrace xeriscaping.
Sedums, especially short, small-leaved varieties, also serve an important sustainable function: They are increasingly being used in green-roof projects around the country.
The concept behind the green-roof movement is simple: A lightweight “blanket” of vegetation covers a roof’s surface, shielding the roof from harsh weather, temperature extremes and ultraviolet radiation. What’s more, the plants remove particulates from the air and reduce storm-water runoff.
Mr. Horvath is a major supplier of green-roof plants in the Midwest. He said he frequently chooses sedums for green-roof installations because these plants have shallow roots, require little soil (which makes them lightweight) and are resilient to diseases and insects. In addition, they thrive with little fertilizer and are adaptable to climate extremes.
I don’t have a green roof, but sedums make up a significant portion of my mixed border. Sedums can transform a lackluster site, especially for gardeners with lean or “disturbed” soil, such as that found with new construction.
Which sedum variety is best for you? ‘Autumn Joy’ is ubiquitous on Long Island and the choice of landscapers everywhere. A good performer, ‘Autumn Joy’ “was the first of the taller varieties to be offered when there were few sedums available,” said Ms. Peterson.
Today, there’s a mind-bogging array of sedums from which to choose. Consider ‘Carl,’ which has a rounded compact habit and clusters of pink flowers held on reddish stems, or ‘Red Cauli,’ which also has red stems, along with burgundy-tinged leaves.
And then there’s ‘Thundercloud,’ a dome-shaped cultivar with pointed, gray-green leaves.
Looking for an unusual accent to light up the garden? A variegated sedum might be in order, such as ‘Frosty Morn,’ which has blue-green leaves edged in white, or ‘Cutting Edge,’ an introduction by Mr. Horvath that has chartreuse-yellow margins.
If you fancy a groundcover sedum, another of Mr. Horvath’s introductions might be just what you are looking for: ‘Red Rock’ features small rosettes of red foliage with hints of green.
No matter what you choose, one thing is clear: “There is a sedum for everyone and every situation,” according to Mr. Horvath.
Susan Tito is a freelance writer and proprietor of Summerland Garden Design & Consulting (summerlandgardendesign.com). She earned a certificate in ornamental garden design from the New York Botanical Garden and is a member of the American Horticultural Society and Garden Writers Association. She can be reached at email@example.com.