Latin Violoa tricolor, V. x wittrockiana, V. odorata Family: Violoaceae
Season & Zone
Exposure: Full sun to partial shade Zone: 3-10
Start indoors 10-12 weeks before planting out. For spring planting after last frost, that means up to 3 months growing time indoors. On the coast you would sow seeds indoors for early spring planting in early January. Otherwise, sow direct outdoors in summer to early autumn. For winter-flowering pansies in Zones 7-9, start seeds in mid to late June. For V. odorata: Direct sow in autumn or early spring. This variety benefits from a long exposure to cool soil.
Even though the seeds are tiny, they need to be sown 5mm (¼”) deep. Keep the soil at 18-25°C (65-75°F), in complete darkness until they germinate in around 14 days. Then provide bright light to keep plants compact. Space at 15-23cm (6-9″) in the garden. For V. odorata: Barely cover the tiny seeds. Sow in flats sunk into the ground against a north-facing wall, and cover with glass or plastic. Remove cover when seedlings emerge. Germination can take up to 50 days, so be patient.
After germination, violas are easy. Fertilize once or twice in early growth and provide a mulch around plants to keep roots cool as weather warms. Deadhead to prevent self-sowing, particularly with Johnny-Jump-Ups.
For V. odorata: Transplant after last frost or in the autumn where winters are mild, spacing at 15-30cm (6-12”) apart. Grow in partial shade, or in full sun where summers are cool. This variety prefers rich, moist, well-drained soil with a pH of 5.5-7.0. Add well-rotted manure at transplant time.