Description: This native perennial plant is up to 6"
tall. It consists of several trifoliate basal leaves on long stalks that emerge
directly from the ground. Among
these leaves, appear floppy umbels of flowers on
slightly taller stalks. The trifoliate leaves are about 1" across and open up
during the day. Each leaf consists of three obcordate leaflets with smooth
margins, which may turn purplish in response to cold weather or strong
sunlight; otherwise, they tend to be greyish green. Each flower is bell-shaped
and a little less than ½" across. The 5 petals are light purple or
violet, but become greenish white with fine lines converging toward the throat
of the flower. These petals often recurve outward and downward when fully open,
displaying the bright yellow anthers. Each flower is subtended by 5 green
sepals that are lanceolate and have orange tips. The entire plant is hairless,
or nearly so. The blooming period occurs during late spring and lasts about a
month. Rarely, Violet Wood Sorrel may bloom again in the fall. There is no
floral scent. Eventually, slender pointed seed capsules develop that split into
5 sections, sometimes ejecting the light brown seeds several inches. The root
system consists of small bulblets with fibrous roots, which can slowly
multiply.
Cultivation: The
preference is full or partial sun, and mesic to dry conditions. The soil can be
rocky or loamy. Disease is not normally a problem as long as the site is
well-drained. This is an easy plant to grow as long as it is not overpowered by
taller vegetation. It fixes nitrogen in the soil by means of endomycorrhizal
bacteria.
Range & Habitat:
Violet Wood Sorrel occurs in every county of Illinois and is fairly common,
although it is often overlooked (see
Distribution
Map). Habitats include mesic to dry black soil prairies, open upland
forests, savannas, bluffs, limestone glades, and abandoned fields. It responds
positively to wildfires as this clears away the dead vegetation that can
smother this plant during the spring.
Faunal
Associations: Primarily small long-tongued and short-tongued bees
visit the flowers for nectar or pollen. This includes Little Carpenter bees,
Nomadine Cuckoo bees, Mason bees, Andrenine bees, Green Metallic bees, and
other Halictine bees. The bee Andrena violae is an oligolege of this
plant and violets that bloom during the spring. Less commonly, the flowers may
be visited by small butterflies or skippers. Syrphid flies also visit the
flowers, but they feed on the pollen and are non-pollinating. The seeds are
eaten to a limited extent by several upland gamebirds and songbirds, including
the Bobwhite, Mourning Dove, Horned Lark, Field Sparrow, Grasshopper Sparrow,
Savannah Sparrow, and Slate-Colored Junco. The Cottontail Rabbit eats this
plant occasionally, even though it is mildly toxic because of the presence of
oxalic acid in the leaves.
Photographic
Location: The photographs were taken at Loda Cemetery Prairie in
Iroquois County, Illinois.
Comments:
In Illinois, this is the only Wood Sorrel with violet flowers that blooms in
sunny areas. The flowers and leaves open up on sunny days, otherwise they fold
up and "go to sleep." It is an attractive, but rather small plant. The leaves
are supposed to be edible in small amounts.