Viola

Violas are essential cottage garden plants that create a mass of low-growing colour, with deep blues, purples and lilacs, rich magentas and purple-pinks, many with quite wonderful combinations. Grow them right at the front of a border.

Violas are similar to pansies, but there are major differences. Violas are dwarf, compact, free-flowering perennials that are often in bloom from March to October. Pansies come from the variably coloured Viola tricolor and are more straggly, often with a large blotch on the lower petals. Pansies are also shorter-lived, being annual or biennial. Which is why, given the choice, grow violas every time.

Recommended varieties

There are scores to choose from, with most only available from specialist nurseries. Those that are widely available give a reliable show of summer colour.

V. cornuta : it flowers from spring to summer with a faintly scented, violet bloom. Popular cultivars include the white 'Alba Group', pale blue 'Boughton Blue' and var. minor, with blue or white flowers. The Liliacina Group has slightly smaller flowers, with narrower petals which give it a slightly wild look. Plants self-seed and will hybridise with other nearby violas; let them grow and save the best. The Royal Horticultural Society (RHS) has given all three its Award of Garden Merit (AGM).
V. 'Eastgrove Blue Scented': vigorous, spreading stems and gently scented lilac flowers made popular by a small nursery in the Midlands.
V. 'Huntercombe Purple': very popular and highly effective, with a large quantity of richly coloured, violet-purple flowers. It's been given the AGM.
V . 'Jackanapes': good fun, highly distinctive, bi-coloured flowers with two chocolate-red upper petals, and the lower ones deep yellow with whiskers. The blooms are held above neat clumps of foliage. It's believed to have been bred in the early 1900s by Gertrude Jekyll, the famous gardener and designer, and named after her pet monkey.
V. 'Maggie Mott': popular for over 150 years, it has a superb fragrance and produces large flowers on vigorous stems. It's got the AGM.
V . 'Molly Sanderson': perhaps the best known of all violas, it's matt black with a small yellow eye. The RHS has handed it the AGM.
V. odorata : the English violet has a late winter-early spring show of faintly scented blue or white flowers.
V. tricolor : heartsease gives a lively spring to autumn display with an attractive mix of purple, lilac, yellow and white. The plants don’t live that long, but they keep scattering seed, giving rise to new clumps. Let them naturalise through a border, wild garden or woodland clearing. They're extremely pretty.

Growing tips

Site and soil preferences

Violas like humus-rich soil with plenty of leaf-mould or well-rotted manure added each spring. They shouldn't require much more feeding - too much fertiliser can encourage soft leafy growth. But you can give a weak liquid feed which is high in potash (for extra flowering) in summer.

Growing in pots

To grow violas in pots, they must be planted in containers that are at least 30cm (12in) deep. Keep them in a semi-shaded position so they don't burn in the sun, especially in the warmer southern areas of Britain.

Planting associations

Violas make a superb combination that's indispensable for growing under roses and other shrubs, providing the soil is kept reasonably damp. The forms of V. cornuta are particularly effective: they're vigorous spreaders which give good ground cover and link up different plants.

The Liliacina Group is lovely for growing in groups of three or five among other small plants towards the front of a border, and beautiful as a carpet below roses or mixed shrubs.

Aftercare

By the middle of summer, some violas may begin to look a bit straggly. They should be cut back to about 7.5cm (3in). This will encourage strong new growth that will start to flower again in a few weeks.

Deadheading

Regular deadheading keeps plants tidy and prevents them from setting seed, which wastes energy that could go into producing more flowers.

Propagation

Take cuttings in August and early September.

Cut a strong shoot 5cm (2in) long and nip off any flowers and buds. This will direct all the shoot's energy into making roots.
Strip off the lower foliage to leave just the top two or three leaves. This may seem drastic, but it limits water loss from the foliage.
Root-growing hormones are concentrated in the leaf node, so making the cut here gets the roots to form more quickly.
Dip in rooting hormone, insert in pots of compost, and water in. Place outside in semi-shade and roots should form in three weeks.