With delicate, prolific blooms reminiscent of open-face snapdragon flowers, diascia is a colorful option for early spring containers or garden beds. Most often diascia is used as a cool season annual, but in some areas it can be considered a perennial.
With small, showy flowers on low-mounding to sprawling plants, diascia can be used interchangeably with alyssum, pansies, nemesia and other cool season annuals. The flowers of diascia come in a range of pinks, whites, corals, and oranges. During cool weather, the plants are covered in blossoms. Once warm summer weather begins, though, plants tend to slow down on flowering or stop blooming completely. But when cool fall weather begins, the plants will bloom once again. Diascia is sometimes referred to as twinspur because the flowers feature two spurs coming out of the back of the blossoms. Within these spurs, the plants produce an oil that is collected by a species of bee that have evolved alongside the plants.
Diascia Care Must-Knows
This South African plant grows best in fertile, well-drained soil with consistent moisture. Diascias tolerate drought once established. These plants will benefit from regular applications of fertilizer, especially during the spring.
Diascia performs best in full sun but it grows in part shade, too. In areas with a warm summer, plants will perform best in part sun, as this keeps plants cool at the expense of just a few less blossoms than plants in full sun. Diascia may not survive the intense heat of a hot summer; these plants should be treated as cool season annuals. In milder climates, diascia can be treated as perennials even though they go through periods of dormancy.
While they do not require deadheading to keep up with their blossoms, diascia will benefit from a shearing back to encourage a flush of new growth. This helps to promote better flowering in the fall, especially when done just before the hottest part of the summer, and after their initial heavy bloom cycle.
One of the breeding goals of diascia is to create new color varieties. The biggest drawback of diascia is its summer dormancy, and work is underway to extend bloom time. There are a few new varieties that tout all-season blossoms, but even these seem to fall short in hot weather. Plant scientists are also working to create more upright types and plants with a better spread.
Related: How to Plant a Border with Annuals