Torenia cultivars produce lots of flowers all season long despite heat and humdity - look for them in pink, white, yellow and shades of blue and purple.
Wishbone flower, or bluewings, is a warm weather annual bedding flower, up to about 12 in (30 cm) tall. The plants branch freely and grow almost as wide as high. The stems and 2 in (5 cm) opposite leaves are glabrous (without hairs). The showy flowers are velvety, about an inch and half (3.5 cm) long and an inch (2.5 cm)across. They resemble other members of the figwort (Scrophulariaceae) family - snapdragon (Antirrhinum majus) and foxglove(Digitalis purpurea). Each flower has a trumpet shaped corolla with a lower lip divided into three blue-purple lobes and a larger upper lip with two pale blue lobes, all with yellow throat spots. The flowers are produced abundantly throughout summer. The cultivar, 'Alba', has white flowers. The 'Clown Mixed' cultivars include pink, white, lavender and purple flowers. The Panda Series of cultivars are small plants, only 4-8 in (10-20 cm) in height. Other cultivars include 'Grandiflora', with larger flowers, 'Compacta', with a very compact habit, and the striking 'Susie Wong' which has bright yellow flowers with brown throats.
The wild wishbone flower was originally from southeastern Asia, Viet Nam in particular.
Feed every couple weeks with a fertilizer high in potassium to promote flowering, and pinch off stem tips to increase bushiness. Light: In warmer climates, wishbone flower can be grown in partial shade to nearly full shade. Morning sun and afternoon shade is best. Up North, grow wishbone flower in full sun. Moisture: Wishbone flower likes a moist soil, rich in organics. Water freely when dry. Hardiness: USDA Zones 6 - 9. Wishbone flower thrives in warm, humid climates. It is a tender annual that needs temperatures above 40°F (5°C). It does not tolerate frost. Propagation: The torenias are readily grown from seed sown in place in early spring, or started indoors ahead of the season. Seed germination is improved by light, so don't bury the seeds - just press them into the soil surface. They also can be started from cuttings.
It's easy to see why the 'Purple Moon' torenia is a favorite cultivar.
Wishbone flower is best used in masses in borders and flower beds. For the best effect, plant them close together, about 6 in (15 cm) apart. This is the hot weather substitute for pansies Viola x Wittrockiana). In Florida, we grow pansies in beds in the winter and wishbone flowers in the summer. They are excellent in hanging baskets, too, where the rather weak stems can trail over the sides.
Inside its corolla tube, wishbone flower has two wishbone shaped stamens that are joined at their tips until the flower is ready for pollination, at which time the stamens pull apart.
The genus Torenia includes some 40 species of perennial and annual herbs from Africa and Asia. It was named by none other than the father of modern taxonomy, Carolus Linnaeus, for a contemporary Swedish clergyman, Olaf Toren. The specific epithet honors the French botanist Pierre Fournier.