Garden Muse

Sedum: Brilliant Summer Survivors

Story and Photos by Paula Steers Brown, Contributing Columnist

 

There is nothing like a trip out West to make you appreciate succulent plants that can survive scorching summers and still look good. Succulent, meaning “full of juice,” characterizes plants with thick, fleshy stems and leaves whose water-storing tissues act as reservoirs to enable them to tolerate drought.

Plants like cacti, aloes and yuccas (which have spines as leaves) have a strong, thick epidermis often densely covered with hair or wax and are equipped with narrow openings that overlap for wind protection. My great aunt, who had lived for many years in Texas , moved east bringing odd-shaped succulents with her that captured my imagination. Her aloe possessed amazing first-aid properties: When anyone got a burn, we would break off a piece of the fleshy stem to rub its healing juices on the burned

area and watch the redness disappear. Her Sempervivum, better known by its charming common name, Hens and Chicks, formed dense rosettes of fleshy leaves. The round mother “hen” flowers, and when the flowers fade, the little offsets that remain are her “chicks,” tiny new copies of the original that make propagation effortless. Fascinating variety of form provides interest in all areas of the garden, from upright yucca to hanging plants like “Strings of Pearls” (Senecio owleyanus), to needle-like groundcover such as Delosperma. One of the most stalwart succulents, particularly adaptable to average soil and offering some of the greatest variety of color, form and design potential, is the ever-popular sedum.

Known for low maintenance, sedum is so easy to grow that it has become quite common in commercial plantings. In fact, the spectabile variety “Autumn Joy” is so prolific that during a phase of plant snobbery, I began to look down my nose at it as overused. I have since wised up and realize that if a plant is that popular, it is usually for a good reason. Its clumping growth pattern makes nice, neat mounds that are easy to control in the landscape. Sedum is also known as “stonecrop” because its more than 400 species are native mainly to the rocky, mountainous regions of the northern hemisphere. All varieties grow well where water-demanding plants fail — next to driveways, tucked into rock walls, in terraced rock gardens. Rock walls not only display succulent plants in a beautiful way but also prevent erosion. The walls should not be vertical but should slope backward about two inches for every foot in height. Every type of sedum from uprights to ground-huggers will look good between the rocks. They love the great drainage and lean soil in a sunny location.

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Bees and butterflies flock to the flowers rich in nectar, and birds love the seed heads. Never deadhead “Autumn Joy,” as it is among the most outstanding of perennials for adding interest to a winter garden when left untrimmed. The spent flowerets with their broccoli-type heads that turn russet look great against the snow or rimmed with frost on a cold morning. You may want to cut just a few stems for arrangements, since sedum has an incredibly long vase life. One of the few things that can go wrong with “Autumn Joy” in the landscape is crown rot, where those flowerets turn black and decay because of too much moisture. So, do not plant them in soil that is either too wet or too rich. Try some varieties with intensely colorful blooms like “Neon” (or its parent “Brilliant”), whose plump, lime-green leaves are a perfect foil to its hot-pink blooms. In a few months, a favorite sign of spring is seeing the first little bright-green knobs emerging at the base of sedum stems. That is the signal it is time to cut the stems back at their base to prepare for the year’s new growth. Some gardeners swear by pinching the stems instead of cutting them to prevent calluses from forming, which could cause breakage in winter weather.

Not only do the perennial blooms of sedum appear in a wide variety of hues, their foliage offers a fine range of color for several seasons of the year. “Purple Emperor” and “Blackjack” are almost black, whereas “Frosty Morn’s” leaves are edged in white. “Matrona” and “Vera Jameson” have purplish foliage while “Carl’s” greenish-gray foliage has striking pink stems and leaf margins. Pair sedum with other autumn beauties — black-eyed Susans, Russian sage, chrysanthemums, grasses, asters or dwarf nandina all make nice companion plants. Trailing “Dragon’s Blood” and “Weihenstephaner Gold” both have the advantage of sporting their red foliage all winter — they are evergreen, or in this case, ever-red. Carpeting groundcovers also sparkle in shades of silvery blue (S. sieboldii) and gold (“Limelight”). Sedum performs beautifully draping over the edges of containers or dish gardens. Especially distinctive as a hanging plant is S. morganianum, with its dangling sausage-shaped branches commonly called Donkey tail.

A green roof favorite

Sedum may have a big future in the Green Movement as a favorite for use on “green roofs,” an ancient concept that was revived in the 1960s in Germany because of its environmental benefits. The low-growing sedum varieties are ideal to use in this situation since they can grow on slopes of up to 30 degrees inclination. A Canadian environmental group found that a green roof can cause a 26-percent reduction in a home’s summer cooling needs, as well as a 26-percent reduction in heat loss in winter, so that widespread implementation in urban settings could reduce temperatures as much as 12 degrees F. The roofs also prove themselves environmentally friendly by providing a habitat for birds and butterflies. Even a very thin layer of rockwool laid directly on a watertight roof can support sedum. Chicago’s City Hall and Dearborn, Michi­gan’s Ford Motor Company both feature green roofs, as do buildings in London, Atlanta, and Portland, Oregon. Who would think such a common plant just adapting to the heat would turn out to be so cool?

© Paula Brown is a freelance writer and lecturer on gardening topics. She lives in Richmond , Va. , where she runs her design business, Imagine That.

 

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