The Common Blue Violet is a native perennial forb, only 4 to 6 inches high.
The leaves are ovate to circular heart shaped, without lobes, but edges with rounded teeth. They are basal only and rise directly from the underground root on long stalks, forming a rosette (whereas the Canada Violet and the Yellow Violet have stem leaves). The lowest leaves in the rosette can have more rounded tips whereas the upper one may be more pointed. Leaf surfaces can vary from smooth to somewhat hairy. Leaf stalks are either smooth or with very fine hair.
The inflorescence is a solitary flower on a hairy leafless aerial stem, also rising directly from the root. The stem curves at the apex with the flower held at the level of the leaves.
Flowers are 5-parted and average 1 inch wide. Flower color varies considerably from medium violet to deep violet and rarely whitish. The 5 petals are of unequal size, have rounded tips and are spreading to slightly reflexed when open. There are two upper petals, two laterals and a bottom petal that is spurred on the back which is a characteristic of the violets grouped under V. sororia. The bottom petal allows insects to alight after being attracted by the other four petals. The lower petal is smooth on the inside while the two side petals have long and slender white hairs. These hairs prevent water from entering and diluting the nectar found behind them. The inner or base parts of the petals are whitish and have vein lines that radiate toward the tips. These lines pick up a deeper violet color, especially on the bottom petal; they function as nectar guides to insects. There are five stamens whose filaments are wrapped around the pistil. The calyx has 5 green sepals that are linear with pointed tips. The upper sepal is usually recurved. There is a second type of flower that does not open but can self pollinate (called cleistogamous flowers), which appear later in the season, both at ground level and sometimes below.
Seed: The chasmogamous flowers - the open ones - can self pollinate or cross pollinate, but seldom set seed as they tend to bloom before there are many insects about. Seed is produced by the cleistogamous flowers, which form a 3 chambered seed capsule, which when mature, unfolds into three arms, splits open and ejects the seeds which are brown, teardrop shape, about 1.5 mm wide by 2 mm long.
Varieties: Over time a number of what were once considered separate species or varieties, have been grouped in V. sororia. Within this group there is considerable color variation in the petals, and variety in leaf shape. Today, the position taken by Flora of North America is that there is no reason for this and the only form that might be treated separately is the color form of V. sororia forma priceana, known as the Confederate Violet where the petals are a grayish white with violet veining. Several former varieties of V. sororia are now separate species such as V. missouriensis, the Missouri Violet and V. affinis, Le Conte's or Sand Violet. Minnesota authorities follow the Flora in this.
Habitat: The Common Blue Violet of meadows and woods blooms in numerous places in the Woodland Garden. Found throughout Minnesota it is difficult to distinguish in passing from the numerous similar violets found in the State. You may have this species growing in your lawn. It grows from a thick horizontal fleshy rhizome. These form laterals which then produce clone plants in large colonies. They prefer rich soils, moist to mesic conditions and only partial sun. In full sun, the plants will dry up in summer when not in a moist location.
Names: In prior years botanists classified the Common Blue Violet as V. papilionacea and the Woolly Blue Violet as V. sororia. The two are now combined as one species as V. sororia Willd. by most botanical references. The genus Viola is the Latin name for various sweet-scented flowers. The species sororia, means 'sisterly', referring to the species resemblance to other species of violets. The author name for the plant classification - ‘Willd.’, refers to Carl Ludwig Willdenow (1765-1812), German botanist, a founder of the study of the geographic distribution of plants. He was director and curator of the Botanic Garden of Berlin.
Comparisons: Common Blue Violet is a member of the leafless class where the flowering stem rises directly from the root without any leaves and there is no separate above ground flowering stem. There are a number of violets in this class. The second class of violets has an above ground stem and it usually has leaves on the flowering stem. This class includes the Canada Violet and the Yellow Violet.
Above: The common blue violet with the flower held just at leaf level.
Below: A deep violet example of flower color. The two lateral petals of this species have slender white hairs which obscure the reproductive parts but prevent water from entering to the nectary area. The lower petal has the purple veined white area which acts as a nectar guide. This petal has no hair but is spurred on the back. The green sepals (2nd photo) are long pointed.
Below: The leaves are all basal and on long stalks, the shape can vary considerably but is generally heart shaped. The underside (2nd photo) is much paler in color and usually has some fine hair.
Below: 1st photo - the cleistogamous flower. 2nd photo - the seed pod unfolded, ready to release seeds. 3rd photo - the teardrop shaped seeds.
Below: The thick fleshy root of Blue Violet with leaves rising directly from the root.
Notes: The Common Blue Violet is indigenous to the Garden area. Eloise Butler catalogued it on May 25, 1907. It was planted frequently. She began planting more of it as early as 1910. In addition, she obtained 169 plants on Oct. 22, 1912 from the area of St. Thomas School in Minneapolis; more on April 25, 1915 from a woods along Superior Blvd. in Minneapolis; another 87 from the same spot in May 1917, more in '18 and '19. On Aug. 28, 1924 she obtained 71 plants from a Mr. E. D. Mayo's Garden. She obtained plants from Groveland Park in St. Paul in some of those years. Martha Crone planted it also, beginning in 1934. The plant is native to almost all the counties in Minnesota. It is one of 21 native violets found in the State. In North America the species if found in the eastern half of the continent except for the Canadian Maritime Provinces.
Caterpillars of various Fritallary butterflies feed on the leaves. V. sororia is the state flower of Illinois, New Jersey, Rhode Island and Wisconsin.
Eloise Butler wrote extensively about violets - Read her notes. Edna Ferber wrote: "Big doesn't necessarily mean better. Sunflowers aren't better than violets."
Dora Read Goodale (1866 - 1915) wrote this poem about Blue Violets.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"