Diascia, commonly called twinspur, produces clusters of spiky pinkish-purple or coral blooms from spring through early summer, sometimes continuing into fall. A low-growing plant that reaches heights of 9 to 12 inches, twinspur works well in rock gardens, containers and hanging baskets. The plant, which doesn't tolerate chilly weather or hot, humid conditions, is often grown as an annual. Twinspur is perennial in U.S. Department of Agriculture plant hardiness zones 8 through 10.
1. Growing Conditions
Twinspur thrives in full sun, but hanging the basket where it gets afternoon shade is helpful if you live in a hot climate. Twinspur performs well in any fresh, high-quality commercial potting soil. Don't use regular garden soil because the soil soon becomes compacted. Garden soil may also carry pests, diseases and weeds. Make sure the hanging container has at least one drainage hole in the bottom. Generally disease- and pest-free, hanging baskets prevent twinspur's main pests -- snails and slugs.
Regular water is critical for twinspurs in hanging baskets because the soil in containers dries quickly. The plant may need water every day -- or more than once a day -- during hot weather. Feel the potting mix first and don't water if the mix feels moist. Although twinspur is relatively disease-resistant, soggy potting mixture may result in rot or other fungal diseases. If the potting mix is dry, water slowly until water runs through the drainage hole.
A potting mix that includes fertilizer in it usually provides enough nutrients to keep twinspur blooming well into its blooming season. But a twinspur planted in a hanging basket often requires supplemental fertilization because the fertilizer is leached through the potting soil. If growth slows and blooming lags, apply a balanced, general-purpose, water-soluble fertilizer in the water once every week. Dilute the fertilizer to one-quarter the recommended solution -- usually 1/4 tablespoon of fertilizer in 1 gallon of water. Read the label to determine the best rate for your product.
Pinching the tips of young twinspur plants one or twice early in the season encourages the plant to branch out, creating fully, bushy growth. To stimulate more blooms throughout the season, remove flowers as soon as they fade. Twinspur doesn't perform well in hot weather and blooming may decrease in midsummer. If blooming slows or the plant begins to look tired and scraggly, cut the plant back by about 3 inches. This keeps the plant neat and often produces a second flush of blooms with the temperature drops in fall.
- Oregon State University Extension: Hanging Baskets
- University of Florida IFAS Extension: Nemesia and Diascia
- The New Sunset Western Garden Book; Kathleen Norris Brenzel, Editor
- The Gardener's A to Z Guide to Growing Flowers From Stem to Seed; Eileen Powell
- Fine Gardening: Genus Diascia (Twinspur)
- University of Arkansas Cooperative Extension Service: Plant of the Week: Twinspur Latin: Diascia Hybrid
- University of Iowa Extension: Growing Annuals in Containers
- Cornell University: Diascia