Diascia barberae aka Twinspur

Diascia barberae is a low perennial from southern Africa. Gardeners know it as twinspur or Barber's diascia. It belongs to the Scrophulariaceae family. It forms a spreading mat rather than an upright clump. Plants reach about 1 foot (0.3 m) tall. They spread to about 1.5 feet (0.46 m) wide. In cold regions, gardeners grow this tender plant as an annual.

Its green leaves have a gloss and toothed edges. Their shape ranges from egg-shaped to heart-shaped. Detailed leaf accounts give a length near 0.08 feet (0.025 m). The leaves lack hairs, and the stems have no scent. North Carolina State lists the foliage as evergreen. Loose racemes rise above the leaves on slender flower stems. These stems reach 0.5–1 foot (0.15–0.3 m) high.

The flowers are rose pink with yellow throat marks. Each bloom has a clear lower lip and two rear spurs. Flowers measure about 0.06 feet (0.019 m) across. Their shape is tubular, with four or five petals. Bloom can run from April until frost. North Carolina State gives the season as spring through fall. Summer heat may halt flowering for a time. The blooms draw both bees and butterflies to the garden.

Twinspur grows best in full sun but accepts part shade. It needs moist soil that drains well. Rich soil with plenty of organic matter suits it. Missouri Botanical Garden recommends moderate soil fertility and moderate watering. North Carolina State lists neutral soil as suitable. Plants do better where the air is less humid. They are winter hardy in USDA zones 8–11. Growth is moderate, as is the level of upkeep.

Use twinspur at border edges, beside paths, or in rock gardens. It also grows in pots and hanging baskets. Pinch young stems to help plants branch and fill out. Remove old flowers to extend the bloom season. Cut plants back when flowering fades to encourage fall flowers. Seeds can start indoors six to eight weeks before the last frost. Direct sowing can begin one to two weeks before that date. Missouri Botanical Garden reports no major insect or disease concerns. Slugs and snails can still cause trouble.