Viola cornuta. We loved this petite pansy as soon as it bloomed, and it bloomed in the first year, over a long period. Just 14 to 16 weeks after seeding, its small, very dark, and flat-faced flowers began to appear. With regular deadheading Back to Black just blooms and blooms. The foliar growth is vigorous, but the stature of the plants remains compact at about 15cm (6") tall. It would look great in containers or window boxes, but it takes on a wonderful appearance in mass plantings. The flowers are actually very deep purple, but so deep that they appear black from a few feet away. Each delicate flower is streaked in the centre by a brush of golden yellow. The edible flower petals look amazing scattered on ice cream. Sow in early spring for summer flowers, or as late as July for winter blooms. It's hardy in Zones 5 to 9.
Hardy annuals and perennials that are variously known as pansies, Johnny-Jump-Up, and Heartsease.
Violoa tricolor, V. x wittrockiana, V. odorata
Season & Zone
Exposure: Full sun to partial shade
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.