Torenia (Torenia fournieri) are annual plants that will add a splash of color to the flower bed with blooms in shades of pink, purple, blue and white. Each bloom has a distinctive wishbone shape, thus the plant's nickname, "wishbone flower." Torenia thrives outdoors until winter temperatures drop below the freezing mark. In cold winter climates, grow torenia as a houseplant, or bring it inside before the first freeze.
Select a planting spot where the torenia will be in partial shade. Torenia should be protected from hot afternoon sunlight, especially in hot, dry climates.
Use a garden fork or a spade to cultivate the soil to a depth of 8 to 10 inches. Add 2 to 3 inches of manure or compost to the soil, and mix it in thoroughly. Containerized torenia plants should be planted in potting mixture for African violets. Be sure the pot has bottom drainage.
Water torenia plants regularly. Never allow the soil to dry out completely, but don't water so much that the soil is soggy. Check containerized, outdoor-grown torenia daily, as soil in containers will dry out very quickly. The plants may need to be watered twice daily during hot, dry weather.
Feed torenia plants every other week during spring and summer, using an all-purpose water-soluble fertilizer. Fertilizing is especially important for toreni grown in containers.
Bring containerized torenia plants indoors before the first freeze in autumn. In-ground plants can be treated as annuals and allowed to die, or placed in containers and brought indoors for the winter. Place torenia in a bright window and continue to keep the soil moist.