When my 15-year-old son practices the drums, his border collie, Rocky, jumps into action. He’ll instinctively grab anything in sight and drag it around the yard as if to herd it like sheep. Recently, Rocky found my Dipladenia, still in its gallon-sized container waiting to be transplanted.
The plant: When my 15-year-old son practices the drums, his border collie, Rocky, jumps into action. He’ll instinctively grab anything in sight and drag it around the yard as if to herd it like sheep. Recently, Rocky found my Dipladenia, still in its gallon-sized container waiting to be transplanted. Rocky has grown with my garden, and I suppose he thinks he’s helping by removing the plant from its container before dragging it to and fro. Although it makes me nuts, I have come to appreciate the ritual because it helps me judge a plant’s vigor. If it survives a go-round with Rocky, it must be sturdier than most.
So far this summer, the winners have been South African jasmine, Goodwin Creek lavender, Angelonia and Dipladenia. This tropical evergreen bush, also named Mandevilla after the 18th-century British diplomat and gardener Henry Mandeville, is up to the challenge. Dipladenia is native to the lower latitudes of South America and is similar to, but not exactly like, the well-known vining hybrid Mandevilla “Alice du Pont.” There’s a botanical tug of war about whether to call this plant Dipladenia or Mandevilla. Botanically, both plants belong to the genus Mandevilla, but because Dipladenia is considered a “sport” -- a plant significantly different from the parent due to mutation from cross-pollination rather than hybridization -- growers continue to use the name Dipladenia to differentiate this bushlike plant from its more vining Mandevilla cousins.
Growing guide: Light sun to partial sun.
Culture: Prepare soil for flowering plant cultivation. Plant from transplant. If possible, choose a spot with sun in the morning and protective shade in the afternoon. A spot on a south wall under an overhang has been suggested as a good placement in the low desert. I have mine along a north wall in a raised bed that gets sun in the morning and shade in the afternoon. Dipladenia will begin to grow in a bushy form, but if unchecked will eventually act vinelike, growing 4 to 6 feet tall.
Space transplants 3 to 4 feet apart. Water regularly to keep soil moist during the summer. Dipladenia doesn’t like cold. wet feet, so adjust the water in winter to allow the soil to dry slightly between waterings. For best success, try growing it in a large container. Dipladenia begins to flower in the Valley around April or when the nighttime temperatures reach 50 degrees. Foliage is dark green and glossy, with flower colors that range from white to deep pinks to red with a yellow throat.
Maintenance: After the plant has been growing for four weeks in the ground, add an organic fertilizer to the soil such as dry bat guano or liquid fish/seaweed emulsion. Feed thereafter with fish/seaweed emulsion once a month if growing in a container. Dipladenias are frost-tender, so take care to cover and mulch on nights when frost threatens. If you are growing in a container, move it up onto the porch or up against a warmer south or west wall on frosty nights. If aphids appear, try washing them off with a stiff spray from the hose. If they persist, try neem oil. Yellow leaves can signal either too much water or not enough water.
Barn Goddess tips: Dipladenia can be planted in containers on terraces, balconies or patios. Use it as a filler in hanging baskets or window boxes. It can also provide a vertical presence if trained up a trellis. The plant pictured here is Red Riding Hood. You may also find “Faire Lady” (white blooming, low growing), or “Scarlet Pimpernel” (scarlet red flowers). Pair Dipladenia with periwinkle-hued plumbago, tropical-colored hibiscus and/or calla lilies. And here’s a final bonus: It attracts hummingbirds and butterflies.
Go to gardenterritory.com. Click on “Organic Gardening” for detailed information on how to prepare soil for flowering plant cultivation.