An excellent container plant because of its consistent show of color, twinspur (Diascia barberae) blooms from early summer to frost on slender spikes of apricot, shell pink, and mauve flowers. Tiny, heart-shaped leaves provide a bright green backdrop for the delicate spikes. The five-lobed flowers might remind you of its relative, the snapdragon. Twinspur’s use is not limited to containers—it’s also attractive combined with annuals or perennials in a border or rock garden.

Common name: Twinspur
Botanical name: Diascia barberae
Plant type: Half-hardy annual
Height: 8 to 12inches, depending on cultivar
Zones: Perennial in Zones 8 to 9
Family: Scrophulariaceae

Planting conditions

  • Sun: Full sun in cooler climates; some afternoon light shade in warmer climates.
  • Soil: Fertile soil with excellent drainage; suffers in heavy clay soil.
  • Moisture: Evenly moist, but avoid overwatering.



Care

  • Fertilizer: In containers, applyfertilizer that has more phosphorus than nitrogen (such as 15-35-15) every other week. Excessive nitrogen causes weak stems and fewer flowers.
  • Mulch: In planting beds, apply a light covering of organic mulch to deter weeds.
  • Pruning: Usually none required.If blooms decrease afterfirst flush of flowering, trim back to encourage more flowering.



Hybrids

  • Flying Colors ‘Apricot’ (pictured) has larger, early-blooming flowers and compact growth. Grows 8 to 12 inches tall. Zones 7 to 9.
  • ‘Blackthorn Apricot’ has apricot flowers and grows 10 inches tall. Zones 8 to 9.
  • Flying Colors ‘Trailing Antique Rose’ grows 6 to 10 inches tall. Zones 7 to 9.
  • ‘Pink Queen’ has light pink flowers and grows 10 inches tall. Zones 8 to 9.
  • ‘Whisper Cranberry’ grows 10 inches tall. Annual.
  • ‘Wink Orange’ grows 8 inches tall. Annual.
  • ‘Wink Pink’ grows 8 inches tall. Annual.



Garden notes

  • Performs best during the cool weather of spring and fall. Flower production may diminish in extremely hot weather.
  • Plant in spring after last frost. Good locations include raised beds, sandy soils, containers, and hanging baskets.
  • For best performance, plant close together, fertilize regularly, and water well during dry spells.
  • Good companions include annual baby’s breath (Gypsophila elegans), cup flower (Nierembergia scoparia), bellflower (Campanula carpatica), and China pink (Dianthus chinensis).
  • Some sources list Diascia integerrima and its cultivars as hardy to Zone 5. Check labels for hardiness when purchasing twinspur.


Pests

  • Slugs and snails occasionally attack plants.



Propagation

  • Sow seeds in early spring when soil temperatures reach 61ºF in early spring.



All in the family

The Scrophulariaceae family includes Angelonia angustifolia, snapdragon (Antirrhinum majus), toadflax (Linaria spp.), scarlet monkey flower (Mimulus cardinalis), Nemesia spp., Penstemon spp., wishbone flower (Torenia fournieri), and spike speedwell (Veronica spicata).



Text by Mary Pestel, photo courtesy Proven Winners, www.provenwinners.com