Mistflower

Scientific Name: Conoclinium coelestinum. Conoclinium comes from two Greek words—konos meaning “cone” and klinion meaning “little bed,” perhaps referring to the part of the plant on which the flowers and fruit grow. The Latin word coelestis means celestial, bringing to mind the color of the sky.¹ Do you think that’s a good way to describe the color of the flowers?

Common Name: Mistflower. Other names include blue mistflower, ageratum, and blue boneset. Ageratum (genus Ageratum) and boneset (genus Eupatorium) both refer to plants closely related to mistflower. Mistflower is so similar to boneset that it was known as Eupatorium coelestinum for a long time.^1,2

Family: Asteraceae (Aster Family). This is one of the largest plant families, with over 32,000 members! Plants in this family are also known as composites, referring to their flower heads which comprise two types of flowers: ray and disk florets. Disk florets are small flowers which are grouped tightly together in the center of the head, while ray florets resemble petals and are arranged around the margins. Some members of this family have both types of flower, while others have just one (mistflower has flower heads that consist entirely of disk florets!). The yellow center of a daisy is a dense cluster of disk florets, and the white “petals” are ray florets. Can you think of any other plants with composite flowers?⁴

Average Height: 1-2 ½ feet

Description: A perennial plant that grows in colonies, spreading through horizontal shoots that can grow roots. The leaves grow opposite each other, attached by stalks up to 1” long to a light green, round stem. The light green leaves are triangular to ovate shaped (about 3” long and 2” wide), have rounded teeth, and have 2 prominent veins running parallel to the center vein. The flowers are borne at the ends of the stems in flat clusters, about 1–3” across. The color ranges from pink to violet to pale blue—even white on rare occasions. The flowerheads are composed of 40-50 disk florets (no ray florets!) with long styles that give them a fuzzy appearance.^1,3,4

Bloom time: Late Jul – Oct

Notes: Although the flowerheads may look similar to those of pink thoroughwort (Fleischmannia incarnata), there are several things that distinguish these plants from each other. While mistflower grows in moist soils of various chemistries, pink thoroughwort usually grows in dry, nutrient-rich soils. In addition, pink thoroughwort has longer stems that tend to sprawl and the flowers are distinctly pink rather than blue. Pink thoroughwort is a rare plant in Virginia.^1,2,4

Range: Found throughout most of Virginia, but absent from some counties in the southwest. Frequent at lower elevations in the mountains, and common in the Piedmont and Coastal Plain.⁴ A plant of eastern and central North America, it is native from Pennsylvania and Illinois south to Florida, and west to Texas and Nebraska. Absent from the upper midwest and introduced in New York, Michigan, and Ontario.^5,6

Geology/Soil: Most frequently found in moist soil. Often growing in rich, loamy or silty soil which can range from basic to slightly acidic.^1,3

Habitat: Most strongly associated with moist locations including floodplain forests, streambanks, and moist to wet meadows. Can also be found in disturbed areas, clearings, ditches, and old fields.^1,2,4

Flora associations: Usually found with a variety of other trees, shrubs, and herbaceous plants adapted for moist soils such as those in floodplains or wet meadows. These include silver maple (Acer saccharinum), boxelder (Acer negundo var. negundo), spicebush (Lindera benzoin), giant goldenrod (Solidago gigantea), honewort (Cryptotaenia canadensis), smooth wood reedgrass (Cinna arundinacea), early wild rye (Elymus macgregorii), and New York ironweed (Vernonia noveboracensis).

Fauna associations: Many insects such as flies, beetles, and moths may visit these flowers for their nectar, while bees may also seek pollen. Although it is not clear whether mistflower is a host plant for any insects, there are species like the Clymene moth (Haploa clymene) which feeds on Eupatorium spp. and may also use mistflower.³

Human associations: No human uses for Conoclinium coelestinum are known, although it is a great native plant for restorations in wet areas!

We want these plants to thrive and for everyone who gets to visit the park to enjoy them, so remember – don’t pick flowers or other parts of the plant!!

1 Taylor, David. “Native Spotlight: Blue Mistflower (Conoclinium Coelestinum).” Kentucky Native Plant Society, 8 Oct. 2023, www.knps.org/native-spotlight-blue-mistflower-conoclinium-coelestinum/. Accessed 21 Nov. 2024.

2 “Vascular Plants of North Carolina.” Ncparks.gov, 2019, auth1.dpr.ncparks.gov/flora/plant_list.php. Accessed 22 Nov. 2024.

3 “Mistflower (Conoclinium Coelestinum).” Illinoiswildflowers.info, 2024, www.illinoiswildflowers.info/wetland/plants/mistflower.htm. Accessed 22 Nov. 2024.

4 Weakley, A.S., J.C. Ludwig, and J.F. Townsend. 2012. Flora of Virginia. Bland Crowder, ed. Foundation of the Flora of Virginia Project, Inc., Richmond. Fort Worth: Botanical Research Institute of Texas Press, pp.275,307.

5 Patterson, Thomas F., and Guy L. Nesom. “Conoclinium Coelestinum – FNA.” Floranorthamerica.org, 2020, floranorthamerica.org/Conoclinium_coelestinum. Accessed 22 Nov. 2024.

6 “NatureServe Explorer 2.0.” Natureserve.org, 2024, explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.155385/Conoclinium_coelestinum. Accessed 22 Nov. 2024.

7 “BRIT – Native American Ethnobotany Database.” Brit.org, 2024, naeb.brit.org/uses/search/?string=conoclinium+coelestinum. Accessed 22 Nov. 2024.

Definitions:

Composite: A member of the Asteraceae family.

Disk floret: One of the small, tubular flowers clustered in the center of a composite flower like a daisy or sunflower.

Ray floret: The petal-like flowers forming the outer ring of flowers in a composite flower.

Style: The portion of the female reproductive parts of a flower that connect the ovary to the stigma.