About half of the counties throughout Ohio offer the opportunity to soak in the magical spectacle of blue-eyed Mary blanketing the woodland floor. It's often found in the dappled light of moist woodlands, forming colonies that cover the ground like a blue blanket for three weeks in early to mid-spring. It grows best when sited in rich, moist soils and needs a good amount of sun through the open canopy in early spring to flower and establish. The delicate central stem ends in a whorl of 2 to 6 bell-shaped flowers with distinctive coloring--the lower lobes are nearly true blue, while the upper lobes are sparkling white. The annual herb is dependent upon each year's seed stock to spread and reproduce. Studies suggest that the seeds both fall to the ground beneath the parent plant and are carried by water to new areas. Blue-eyed Mary has an interesting growth habit in which the seeds lie dormant through summer until germinating in the fall. Two to four leaves develop, then the growth is suspended through winter until its resumption in late or early spring (Baskin and Baskin 1983; COSEWIC 2000).
Blue-eyed Mary is found throughout the eastern and midwestern US. Canada is especially interested in recovering the species, which is listed there as extirpated and nationally historic. "It's one of only a few native winter annuals that grows in rich deciduous woodlands in the eastern United States and Canada, and is one of only a few (in its family) occurring in eastern North America that is a spring ephemeral," (Committee on the Status of Endangered Wildlife in Canada). The genus name honors Zaccheus Collins (1764-1831), a Philadelphia botanist. The species name is the Latin word for "spring" and refers to the flowering time.
Native habitats include moist to mesic deciduous woodlands or floodplains, wooded lower slopes of river valleys, and areas along woodland paths. It also occurs in drier deciduous woodlands although flowers may be smaller. The size can vary greatly depending on level of moisture and fertility of the soil. Blue-eyed Mary is an indicator species of high-quality woodlands.
Plant Characteristics:
Grows 4-12" tall.
Prefers dappled sunlight/light shade.
Prefers moist to average loamy soils.
Blooms for 3 weeks mid-April to early May. Each flower is ½-¾" across, consisting of a green calyx with 5 teeth and a blue/white corolla divided into an upper lip of 2 rounded, white lobes and a lower lip of 3 lobes; the 2 outer lobes are blue and the tiny middle lobe is folded and hidden from view. The middle lobe contains the stamens and style of the flower. Each flower is replaced by a glovoid capsule that contains a few large seeds.
Opposite, green to yellowish-green leaves are up to 2" long and are often softly hairy. Basal leaves, which are the smallest leaves, are oval with a few blunt teeth on the margins. Middle leaves, which are the largest leaves, are oval to broadly lanceolate with a few blunt teeth on the margins. Uppermost leaves are usually lanceolate with smooth margins.
The root system consists of a slender taproot.
Reproductive System: Blue-eyed Mary is self-fertile but is mostly pollinated by bees.
Wildlife Value:
Host plant for larvae of bilobed looper moth, which also feeds on sunflower, monkeyflower, and wild geranium. The nectar and pollen attract the following bees, which provide the majority of pollination services: honey, bumble, little carpenter, long-horned, and mason. Other visitors include butterflies, skippers, dance flies, and the giant bee fly.
Resources:
Govt of Canada: https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/recovery-strategies/spring-blue-eyed-mary-2010.html
Illinois Wildflowers: https://www.illinoiswildflowers.info/woodland/plants/be_mary.htm
Lady Bird Johnson Wildflower Center: https://www.wildflower.org/plants/result.php?id_plant=cove2
ODNR: https://ohiodnr.gov/discover-and-learn/plants-trees/flowering-plants/blue-eyed-mary