Violet (Viola)

Violet, Violets

Violas are gorgeous and cheery plants that can be grown throughout the year, brightening up a winter container or adding much-needed color in early spring. Violas are widespread in popularity and are generally thought to have originated in France, Spain, China and parts of Asia, with a preference for Alpine areas. The Latin name is Viola and includes a large number of varieties of plants. Commonly known as ‘Heartsease’, Violas were said to have been used in love potions.

I. Appearance and Characteristics 

Viola is a genus of flowering plants in the violet family Violaceae. It is the largest genus in the family, containing over 680 species. Most species are found in the temperate Northern Hemisphere; however, some are also found in widely divergent areas such as Hawaii, Australasia, and the Andes.

Some Viola species are perennial plants, some are annual plants, and a few are small shrubs. Many species, varieties and cultivars are grown in gardens for their ornamental flowers. In horticulture, the term pansy is normally used for those multi-colored, large-flowered cultivars which are raised annually or biennially from seed and used extensively in bedding. The terms viola and violet are normally reserved for small-flowered annuals or perennials, including the wild species.

Annual or perennial caulescent or acaulescent (with or without a visible plant stem above the ground) herbs, shrubs or very rarely treelets. In acaulescent taxa the foliage and flowers appear to rise from the ground. The remainder have short stems with foliage and flowers produced in the axils of the leaves (axillary).

Viola typically have heart-shaped or reniform (kidney-shaped), scalloped leaves, though a number have linear or palmate leaves. The simple leaves of plants with either habit are arranged alternately; the acaulescent species produce basal rosettes. Plants always have leaves with stipules that are often leaf-like.

The flowers of the vast majority of the species are strongly zygomorphic with bilateral symmetry and solitary, but occasionally form cymes. The flowers are formed from five petals; four are upswept or fan-shaped with two per side, and there is one, broad, lobed lower petal pointing downward. This petal may be slightly or much shorter than the others and is weakly differentiated. The shape of the petals and placement defines many species, for example, some species have a “spur” on the end of each petal while most have a spur on the lower petal. The spur may vary from scarcely exerted (projecting) to very long, such as in Viola rostrata.

Solitary flowers end long stalks with a pair of bracteoles. The flowers have five sepals that persist after blooming, and in some species the sepals enlarge after blooming. The corolla ranges from white to yellow, orange or various shades of blue and violet or multicolored, often blue and yellow, with or without a yellow throat.

The flowers have five free stamens with short free filaments that are oppressed against the ovary, with a dorsal connective appendage that is large, entire and oblong to ovate. Only the lower two stamens are calcarate (possessing nectary spurs that are inserted on the lowest petal into the spur or a pouch). The styles are filiform (threadlike) or clavate (clubshaped), thickened at their tip, being globose to rostellate (beaked). The stigmas are head-like, narrowed or often beaked. The flowers have a superior ovary with one cell, which has three placentae, containing many ovules.

After flowering, fruit capsules are produced that are thick walled, with few to many seeds per carpel, and dehisce (split open) by way of three valves. On drying, the capsules may eject seeds with considerable force to distances of several meters. The nutlike seeds, which are obovoid to globose, are typically arillate (with a specialized outgrowth) and have straight embryos, flat cotyledons, and soft fleshy endosperm that is oily.

II. How to Grow and Care

Sunlight

Violas prefer sun over shade, but they don’t like heat. This isn’t a problem in cool spring temperatures. But when planting in the summer, make sure they get some shade during the hottest part of the afternoon.

Temperature and Humidity

Violas love the cool weather of early spring, and thrive in milder temperatures from 40 to 70 degrees Fahrenheit. Mulch and water will help offset the stress of high temperatures.

With proper care, violas can bloom all summer and most will bloom again in the fall. Or, particularly in hot, southern climates, they can be removed and replaced with another flower during the summer and then planted again when cooler weather returns in the fall.

Watering

Water regularly, but allow the soil to dry out between waterings. They can tolerate some drought but will bloom best with regular watering.

Soil

Pansies and the other violas are best grown in humusy, moist soil, such as a peat-based potting mix, or garden soil heavily amended with organic material. Violas like a slightly acidic soil; peat moss as a soil additive will help slightly acidify garden soil.

Fertilizing

Mix a slow-release fertilizer into the soil. Fertilize in the spring and again in late summer to promote a fall bloom.

Pruning

To promote blooming and extend the flowering period, remove or deadhead faded flowers by pinching off the blooms at the base of the flower stem. You can revive leggy or overgrown plants by cutting them back to about 3 to 4 inches tall.

Propagation

Violas are easy to start from seed. They are quite happy to self-seed all over your garden, but in cold climates, the volunteers might not bloom until quite late in the season. If you would like to start your own indoors, the process is very straightforward. Start seed about 8 to 12 weeks before transplanting. Mature violas can withstand occasional freezing temperatures, but new transplants may be damaged if exposed to a freeze. Warm climate gardeners transplanting in the fall should start their seeds in midsummer.

  • Fill small pots or flats with sterile potting mix to about 1/4 inch below the top edge. Sprinkle two to three seeds in each cell or pot, and cover lightly with the more moistened potting mix. Violas need darkness to germinate, so cover the seeds completely.
  • Set in a warm (65 to 70 degrees Fahrenheit) location, and keep moist. On top of the refrigerator is a good spot. Seeds should begin to germinate in 10 to 14 days. Once the seeds sprout, move them to a sunny window or place them under plant lights.
  • When the first true leaves appear, you must thin the pot or cell to the strongest-looking seeding by pinching or cutting the others at the soil line. At this point, a temperature of 55 to 60 degrees Fahrenheit is fine. You can also begin feeding your seedlings with any good balanced, water-soluble fertilizer.
  • When temperatures and weather permit transplanting outdoors, begin to harden off the seedlings by giving them increasingly long visits outdoors over a period of 10 to 14 days. Start with one to two hours of sunlight, and gradually increase their exposure. Make sure the soil stays moist during this hardening off period.
  • Once the seedlings have grown accustomed to full days outdoors, you can plant them permanently into the garden or into their outdoor pots.

You can also grow from seeds sown directly into the garden, though this works best in regions where there is a long growing season. Carefully prepare the planting area by amending it with organic matter, and then loosen the soil and sprinkle seeds. Cover with about 1/4 inch of soil, and water well. Keep the seedbed moist. As the seedlings develop, thin them to about 6 to 8 inches apart, transplanting the excess seedlings to other locations.

Repotting

If you live in an area with hot summers but want to keep your Violas for the next season, carefully dig out of their current position and transplant to a shadier spot or garden container until the hot weather has gone.

Equally, if your Violas are in pots, move the pots to a shadier area to bring them back out once the heat of the summer has finished. This is a good opportunity to cut back the Viola plants – remove any dead stems and deadhead. Violas respond well to deadheading and it is in fact an important part of Viola care. Deadheading will encourage repeat flowering.

Pests and Diseases

  • Common Pests & Plant Diseases

To avoid gray mold, don’t let your plants sit in cool, wet conditions. And make sure your violas get plenty of sunshine and have good air circulation. If you notice aphids, wash the plants off with a strong stream of water. Or for severe problems, treat them with insecticidal soap.

  • Common Problems With Violas

While violas are generally some of the easiest plants to grow in your garden, you’ll occasionally have small problems you can fix without too much trouble.

Brown Spots on the Leaves

Violas can succumb to a number of fungal diseases, such as leaf spot or anthracnose. All can be remedied by removing the affected leaves with clean garden shears and treating the viola with a fungicide.

Drooping Leaves or Flowers

Drooping leaves or flowers can happen for several reasons, including too much or too little water or overcrowding. This problem is easily remedied once you troubleshoot the source. If it’s a problem with watering, stick your finger into the soil to see whether it’s too dry or too moist, and adjust accordingly. If your violas look like they need more breathing room, replant with more space in between the plants.

Overwintering

Violas do survive the winter in warm climates. And through the winter, violas can even continue blooming in these zones. Be sure to check the hardiness zones on your particular variety, as some have more cold tolerance than others.

Continue to fertilize throughout the winter; a liquid fertilizer is often better than granule for easier absorption if there’s frost on the ground. Then, just make sure your violas are getting enough sun and not sitting in soggy soil. If your area is expecting unseasonably cold weather, add a couple inches of straw or mulch over your violas to help insulate the roots.

III. Uses and Benefits 

  • Culinary uses

When newly opened, Viola flowers may be used to decorate salads or in stuffings for poultry or fish. Soufflés, cream, and similar desserts can be flavored with the essence of Viola flowers. The young leaves are edible raw or cooked as a mild-tasting leaf vegetable. The flowers and leaves of the cultivar ‘Rebecca’, one of the Violetta violets, have a distinct vanilla flavor with hints of wintergreen. The pungent perfume of some varieties of V. odorata adds inimitable sweetness to desserts, fruit salads, and teas while the mild pea flavor of V. tricolor combines equally well with sweet or savory foods, like grilled meats and steamed vegetables. The heart-shaped leaves of V. odorata provide a free source of greens throughout a long growing season, while the petals are used for fragrant flavoring in milk puddings and ice cream or in salads and as garnishes.

A candied violet or crystallized violet is a flower, usually of Viola odorata, preserved by a coating of egg white and crystallized sugar. Alternatively, hot syrup is poured over the fresh flower (or the flower is immersed in the syrup) and stirred until the sugar recrystallizes and has dried. This method is still used for rose petals and was applied to orange flowers in the past (when almonds or orange peels are treated this way they are called pralines). Candied violets are still made commercially in Toulouse, France, where they are known as violettes de Toulouse. They are used as decorating cakes or trifles or included in aromatic desserts.

The French are also known for their violet syrup, most commonly made from an extract of violets. In the United States, this French violet syrup is used to make violet scones and marshmallows. Viola essence flavors the liqueurs Creme Yvette, Creme de Violette, and Parfait d’Amour. It is also used in confectionery, such as Parma Violets and C. Howard’s Violet candies.

  • Medicinal uses

Many Viola species contain antioxidants called anthocyanins. Fourteen anthocyanins from V. yedoensis and V. prionantha have been identified. Some anthocyanins show strong antioxidant activities. Most violas tested and many other plants of the family Violaceae contain cyclotides, which have a diverse range of in vitro biological activities when isolated from the plant, including uterotonic, anti-HIV, antimicrobial, and insecticidal activities. Viola canescens, a species from India, exhibited in vitro activity against Trypanosoma cruzi.

Viola has been evaluated in different clinical indications in human studies. A double blind clinical trial showed that the adjuvant use of Viola odorata syrup with short-acting β-agonists can improve the cough suppression in children with asthma. In another study intranasal administration of Viola odorata extract oil showed to be effective in patients with insomnia. Topical use of an herbal formulation containing Viola tricolor extract also showed promising effects in patients with mild-to-moderate atopic dermatitis.

  • Other uses

Viola odorata is used as a source for scents in the perfume industry. Violet is known to have a ‘flirty’ scent as its fragrance comes and goes. Ionone is present in the flowers, which turns off the ability for humans to smell the fragrant compound for moments at a time.

Violet (Viola) Details

Common name Violet, Violets
Botanical name Viola
Plant type Annual
Hardiness zone 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
Growth rate Fast
Harvest time Summer
Sunlight Dappled Sunlight (Shade through upper canopy all day)
Soil condition High Organic Matter
Flower color Blue
Leaf color Green