Looking for one last garden project to close out the season? Try growing cold-hardy annual violas. Easy to grow from seed or purchased seedlings, violas are more willing to bloom in cold weather compared to larger-flowered pansies, and most are fragrant. Best of all, modern violas have been bred to bloom like crazy, starting at a young age and continuing until they succumb to summer heat.
Violas are fabulous when grown in beds or containers. They are premier companions for tulips and other spring-flowering bulbs, and they also are welcome in the vegetable garden, where they attract solitary bees and other pollinators, and often reseed in hospitable spots. The flowers and young leaves of all violas are edible. Viola petals have a mild peppery flavour, and they are packed with vitamin C. The fibrous leaves carry a hint of mint.
First introduced in 2012, the Sorbet variety series set a new standard for beautiful, vigorous violas
What Are Violas?
Sometimes erroneously called mini-pansies, violas are descended from a different branch of the violet family tree from pansies. They are classified as Viola cornuta, though other species have been involved in this flower’s hybridisation. Once called horned or tufted violet and native to Spain, the original perennial species was slightly fragrant and longer stemmed compared to johnny jump-ups (V. tricolor), Europe’s common wild pansies. Breeding work began in the 1860s, but the biggest advances took place in the 1990s. Today violas are available in a full range of colors that bloom like mad every chance they get. Recent winners of the Royal Horticultural Society’s Award of Garden Merit include ‘Rocky Denim Jump Up’ and several varieties from the Bel Viso series.
Photo from the overwintering field trials of violas and pansies at Cornell University in New York. The plants on the right were protected with straw mulch from late November to March.
Overwintering Violas
Well rooted young plants can tolerate winter temperatures to -10°F (-23°C), especially when they are mulched. In an overwintering trial at Cornell University in Ithaca, New York, fall-planted violas and pansies greatly benefited from a straw mulch spread 3 inches (7.5 cm) over the plants in late November and removed in March. The mulch protected the plants from cold winds and limited heaving of the soil from freezing and thawing.
Violas grown in containers are less cold tolerant, and may be damaged by freezing and thawing of the roots combined with cold, drying winds. Yet they are perfectly at home in an unheated greenhouse, high tunnel, or cold frame, or you can keep plants in a warm spot on your deck or patio. Overwintering violas in small containers makes it easy to bring them indoors during periods of harsh winter weather, or to protect them from rabbits and deer which find the plants to be a satisfying snack.
Violas grow very little in midwinter due to short, cool days, though greenhouse-grown plants often start popping blooms after Christmas. New growth takes off as days become longer in late winter, and frost-tolerant plants are covered with flowers by mid spring.
With or without deadheading, vigorous varieties like Deltini Honeybee bloom heavily from mid-spring onward
Deadheading Violas
Violas are fast to start producing teardrop-shaped seed pods, and it’s a good idea to snip these off of young plants to help channel energy to new flowers and leaves. But after a while viola flowers and seed capsules come on so fast that there’s no keeping up with them. It turns out this is no big deal. In a 2024 Royal Horticultural Society study at Hyde Hall, Essex, deadheading violas every few weeks made no difference in their appearance or flower power.
Volunteer Violas
Violas shed scads of round seeds, which are eaten by ants, slugs and other garden residents. Yet many survive, with volunteer violas popping up in walkway crevices or other surprising spots. The plants are so small and wimpy that they can hardly be called weeds, yet they are to those who don’t want to see flowers in their lawns. Most gardeners are delighted to find little viola volunteers peeking out from under the daylilies, or close to the previous year’s pots.
A small native bee gathers nectar from a viola blossom
The flowers produced by volunteer plants may not be exactly like their parents, with unexpected changes in colour and colour combinations. Viola flowers are pollinated by many different types of bees, from small sweat bees to big bumblebees, and rich viola nectar is also of interest to butterflies. Genetically speaking, insects always mix things up. When an insect moves from a blue viola to a yellow one, for example, the next generation of seeds may produce blossoms showing both colors. But then, welcoming volunteers is part of the fun of growing trouble-free violas.