Native Violets

"What is a weed? A plant whose virtues have never been discovered." —Ralph Waldo Emerson

For years, advocates of lawns and turf have targeted the violet Viola as a noxious weed. But contrary to their reputation, violets do have their virtues. If attempting to grow a groundcover native to Pennsylvania, where possibilities are limited, consider violets. There is wintergreen (Gaultheria procumbens), partridgeberry (Mitchella repens), various mosses, and perhaps princess pine (Lycopodium obscurum) if the situation is just right. All these choices are slow-growing. Violets, however, work in many challenging landscape conditions. They are vigorous and form dense mounding clumps approximately 5 to 7 inches from the ground.

Ironically, some of their positive attributes are posed to mark them as criminals in the monoculture of the suburban lawn. Violets are notorious for spreading everywhere, especially when they are happy. While this characteristic makes them a good candidate for groundcovers, violets have been known to choke out other plants. They spread by underground rhizomes and can form resilient vegetative colonies. Their waxy, heart-shaped leaves add to their toughness. These evolved to help protect them from some predators, but the leaf's coating has also proven to deter over-the-counter herbicides. They are so irrepressible that they can even grow under black walnut trees.

In addition to rhizomes, they employ multiple schemes for spreading, each strategy aiding in the support of pollinators. Blooming in spring, a variety of Hymenoptera, such as sweat bees and mason bees, emerge from the ground and other nesting sites to feed upon the nectar that violets supply. In addition to their small showy blooms, violets have a second set of flowers that grow near the soil surface but never actually open. These flowers are called cleistogamous or non-opening. They self-pollinate, then mechanically eject seeds in the late summer and early fall to establish a new colony away from the parent. Like trilliums and trout lily (Erythronium americanum), violets also use seed dispersal by ants, a process known as myrmecochory. Their seeds have elaiosomes attached to them, which are fatty deposits attractive to ants. The ant finds a seed, eats the nutritious coating, then buries it. No wonder violets do so well in landscapes.

Indeed, violets attract many other forms of wildlife that delight in their seeds, leaves, and rhizomes. These include songbirds, wild turkeys, grouse, bobwhites, mourning doves, and mice, among other small mammals. The leaves host the larvaelabradorica for several caterpillar species, including the great-spangled fritillary (Speyeria cybele), the meadow fritillary (Boloria bellona), the Aphrodite (Speyeria aphrodite), and the variegated fritillary (Euptoieta claudia).

The visible flowers of violets have five petals, two pointed up, and three pointed down. They are not just blue, violet, or purple; those shades are frequently dominant. A wide spectrum of color possibilities exists, including white, yellow, and combinations of all of the above. There are an estimated 500 species that appear in temperate zones around the world, while in North America, at least 200 species have been identified. They hybridize easily with scores of subspecies and variations, too. The common blue violet (Viola soraria) exhibits a whitish throat and dark veins that radiate out toward the petals; there is the downy yellow (Viola pubescens); the kidney-leaved white violet (Viola renefolia); the American dog violet (Viola labradorica), a pale lavender; and a list of other species that reads on and on. The nursery trade offers many cultivars as well. Viola walteri 'Silver Gem' has silver leaves. Most species like moist conditions with partial shade, but some, like the common blue violet, will tolerate full sun and clay soils.

As more and more gardeners and homeowners undertake lawn conversions by planting front yards with native alternatives, violets are a natural choice. In a bit of a role reversal, some homeowners have used violets to fill in among shady spots where turfgrass has failed to thrive. Consider including them in landscapes and lawns, or just leaving them where they are doing well. Violets are amazing.