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For The Garden

Exotic Stapelias

Author: Cathy Cromell
Issue: April, 2013, Page 65
Photos by Garrett Cook

Many stapelias love morning sun and filtered afternoon shade, says gardener Sue Hakala, shown with her husband, Terry.



Sue Hakala Tends an Unusual Succulent Collection That Offers Otherworldy Blooms

Nose-wrinkling odor isn’t an attribute most gardeners associate with flowers. However, Sue Hakala experiences joy when unpleasant aromas arise in her Mesa, Arizona, backyard because it signals that her Stapelias are in bloom. These South African succulents produce flowers that are unique in both aroma and appearance. “Truthfully, stapelia plants aren’t very interesting to look at, but their blooms are so bizarre that it makes growing them a lot of fun,” she remarks.

Commonly called “carrion flowers,” blooming stapelias produce a rank smell that attracts flies, the plant’s primary pollinator. Flowers are rimmed with tiny hairs that shimmer and flutter to lure the insects. Hakala points out that flies appear only during brief flowering periods and are so busy with the blooms that their presence is not bothersome.

The distinctive five-lobe shape depicts the blooms’ other common name, “starfish flowers.” Colors include lemon yellow, neon green and dusky red, highlighted with speckles or other patterns. “Visitors to my yard tell me they’ve never seen anything quite like them,” the gardener comments. (If odoriferous flowers don’t suit you, Stapelia erectiflora and S. flavopurpurea offer exotic starfish shapes and a more pleasant aroma.)

Unpredictability is another stapelia characteristic that appeals to Hakala. “It’s impossible to predict when, or if, the plants will bloom,” she says. They may flower in late spring or fall or skip a year. “A particular plant’s flowers may look different each season that it blooms. Or two flowers blooming at the same time on the same plant may be different. It’s such a sense of discovery for me to see what appears.”

For 30 years, Hakala has studied and tended her varied collection, learning their growing requirements through reading, sharing experiences with fellow members of the Central Arizona Cactus and Succulent Society, and trial and error. If you would like to try your hand at growing these unusual and rewarding succulents, consider Hakala’s advice as a starting point.

VANQUISHING MEALY BUGS
Although not difficult to grow, stapelias are highly susceptible to mealy bugs. “When enthusiasts meet, the major topic of conversation is how to eliminate them,” jokes the gardener. Use a magnifying glass to scan for these grayish flat oval pests, which often hide in the crevices where stems meet roots. She suggests buying plants locally, rather than ordering online, so you can examine them before purchase. “Years ago, I made the mistake of not examining and treating for these pests, and I lost dozens of plants.”

As soon as you bring new plants home, submerge the roots and bases of the stems in isopropyl (rubbing) alcohol for about 30 seconds. Let the plants dry outdoors in the shade for a few days. Submerge a second time and let dry completely for a few more days before transplanting. Segregate new transplants for several weeks while continuing to monitor for pests.

After planting, dabbing mealy bugs with Q-tips dipped in rubbing alcohol is often suggested as a control method, but in Hakala’s experience, it doesn’t work. “Instead, if I find mealy bugs, I fill a spray bottle with undiluted rubbing alcohol and spray the entire plant so that it gets into all the tiny spaces where bugs or eggs may be.”

Photos - From left: The gardener says this Stapelia flavopurpurea (above left) has had as many as 17 flowers open at once. Huernia zebrina (above right) had 24 flowers at one time.

TRANSPLANTING
Hakala grows some of her stapelias directly in the ground but prefers containers, which can be moved throughout the year to locations with the best growing conditions. If reusing pots, sterilize them first by adding one cup of bleach to a 5-gallon bucket of water and soak pots overnight. Scrub with a brush and rinse thoroughly. If you reuse small rocks as mulch top-dressing, sterilize in the same manner. “I learned this technique at the Desert Botanical Garden, and it has served me well for all of my container plants,” notes Hakala.

Start with fresh cactus soil mix. Avoid mixes that have a lot of bark mulch or other organic matter. Add pumice (2 parts soil mix to 1 part pumice). If you can’t find pumice, substitute quarter-inch minus gravel. The goal is to create a loose, quick-draining soil with good aeration to prevent root rot.

To transplant, fill the bottom third of the pot with pebbles. Fill the middle third of the pot with soil and pumice mix. Top off with a layer of quarter-inch minus
gravel, set the plant on top so that it doesn’t touch the soil, and sprinkle more gravel around it for support. “Growing in their natural habitat, the plant body doesn’t come into contact with soil,” describes Hakala. Stiff, waxy roots at the base of the plant are partially exposed to the elements and grow through rocky surfaces. “After I began mimicking those growing conditions in my pots, overall plant health improved dramatically.”

Photos - Clock-wise from top left: Stapelia gigantea • This blooming Stapelia grandiflora grows under a mesquite tree and flowers nonstop during the warm months, according to Sue Hakala. • The homeowner grows more than 200 potted cacti and succulents in shade houses that her husband, Terry, built. Hakala finds that stapelias do well in containers and in the ground as long as they get afternoon shade and protection • Stapelia kwebensis starts blooming in early September and continues until around Christmas.
 
SUNLIGHT AND MAINTENANCE
“It’s a fine line between sufficient direct sun and too much of the low desert’s intense sunlight,” notes Hakala. Her stapelias receive direct sunlight until 11 a.m., and then filtered light for the remainder of the day under 40-percent shade cloth or the dappled light beneath a mesquite tree. She planted the mesquite years ago specifically to offer this type of sun protection.

Maintenance schedules are tied to plant growth periods when stapelias use more water and fertilizer. In the low desert, their prime growing season is late May through November. In the cold of winter and heat of summer, it is essential to reduce watering to prevent rot.

“Spring and fall, I water when the soil dries out, which varies, depending on the temperature,” explains Hakala. In summer, she waters about every seven days, less when it is humid, and not at all if rain falls on the plants. During winter, when nights are cold, she waters very lightly—only about two times—to barely moisten the roots.

After reading an article in the Cactus and Succulent Journal by long-time grower Elton Roberts, Hakala incorporated his advice into her routine. She adds 1 tablespoon of white vinegar and 1 tablespoon of ammonium sulfate fertilizer (21-0-0) to 5 gallons of water and uses this mix whenever she waters. “According to Roberts, vinegar acidifies the water to allow better nutrient uptake,” she explains.

Hakala also recently started additional feedings using 20-20-20 fertilizer at half strength, applied during active growth periods. “I feed once in mid-May and again in June; then stop during the heat. I start up again, feeding once in late August, September and October.

“After making these fertilizer adjustments, I’ve noticed tremendous improvement, with more abundant roots and blooms, and the plants look healthier overall,” Hakala states. Also, practicing the above sterilization methods, along with regular monitoring and treatment, has eliminated mealy bugs from her collection. “It’s all been worth it to enjoy these otherworldly blooms.”

Stapelia leendertziae makes an excellent groundcover, notes Sue Hakala. The blooms are waxy and about 4 inches long.

The tiny maroon hairs on the yellow Orbeopsis lutea flower move in the breeze to attract pollinators.
Stapelia roots are tough and waxy. Dividing and repotting every two years encourages new growth and blooms.

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