By Kendall McDonald (EEC)
June 20th-26th is National Pollinator Week, an annual internationally celebrated event to educate, support and celebrate all things pollinator conservation. As plant enthusiasts, we have an appreciation and respect for pollinators’ complex and fascinating relationship to plant reproduction. The most well-known pollinator is probably the Monarch Butterfly, which has been reared by school children for decades in lessons about the butterfly life cycle. The monarch has captured the wonder of the public with its spectacular migration, with millions of monarchs traveling up to 3,000 miles to central Mexico and the California coast to overwinter annually.
Unfortunately, since the mid-1990s, the eastern monarch population (accounting for 99% of all North American monarchs) has declined by approximately 85%. There are six major threats to monarchs that have caused this major decline: loss of breeding habitat, climate change, loss of overwintering habitat, natural enemies, pesticides, and general anthropogenic factors. In response to the population loss, monarchs are currently on the candidate waiting list for Endangered Species Act protection. The U.S. Fish and Wildlife Service has a 2024 deadline to propose them for protection as threatened.
Mexico’s Commission of Natural Resources and WWF Mexico conduct annual counts of monarchs in the overwintering locations, oyamel fir forests of high-elevation mountaintops in central Mexico. To truly count millions of monarchs would be a monumental task, therefore the population is reported as an estimation of area of monarch populated overwintering habitat. The most recent count was reported as 7 acres (2.84 hectare) of occupied overwinter habitat, which is well below the 14.8 acres (6 hectare) threshold scientists say is needed to keep the monarch out of the risk of extinction in North America.
In the United States, monarchs have lost up to 165 million acres of breeding habitat due to herbicide use and anthropogenic development. Monarchs rely on milkweed species (Asclepias sp.) as a host for laying eggs and as food when they are caterpillars. Historically, milkweed species were much more widespread and abundant. Between 1999 and 2012, milkweed numbers across the midwest declined by an estimated 64% due to threats such as habitat loss, anthropogenic development, and herbicide use.
One of the easiest things to do to help monarch populations is to provide breeding habitat by planting native milkweeds. Kentucky has 13 native milkweeds, and several species are available at native plant nurseries across the state.
List of Kentucky Resources for Purchasing Milkweed
- KNPS list of Kentucky Native Plant Suppliers & Service Providers https://www.knps.org/native-plant-suppliers-service-providers/
- Contact your local Wild Ones chapter: https://wildones.org/chapters/
- Monarch Watch’s Bring Back the Monarch Program: https://monarchwatch.org/bring-back-the-monarchs/milkweed/
Kentucky’s Native Milkweeds
Asclepias amplexicaulis, Clasping Milkweed
Clasping Milkweed is found in sandhills, barrens, woodlands, and dry, sandy or gravelly soils. Its common name refers to the way the opposite leaf bases wrap around or “clasp” the stem. The Clasping Milkweed is an upright milkweed with an unbranched stem, with a single rounded cluster of pink purple flowers at the top. The flowers have a sweet fragrance similar to that of roses and cloves. This species is uncommon throughout Kentucky.
Asclepias exaltata, Poke Milkweed
The Poke Milkweed can be found in moist forests, slopes and forest margins. It has petioled, non-linear, opposite leaves that occur along erect to ascending stems. The flower umbels are relatively open and droop from long pedicels. Flowers of the Poke Milkweed are bi-colored, displaying a lovely composition of green to pale purple petals and white to light pink hoods and column. This species is uncommon in Kentucky, occurring in the Appalachian Plateau and Interior Low Plateau.
To learn about planting Poke Milkweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-exaltata/
Asclepias hirtella, Prairie Milkweed (State Threatened)
The Prairie Milkweed is a State Threatened milkweed species that occurs in limestone glades and prairies. It has erect to ascending stems that can range from glabrous to densely pubescent, with widely spreading to ascending alternate, linear leaves. Flowers develop from the axils of the middle to upper leaves, occurring in dense globoid umbels of white to green flowers.
Asclepias incarnata var. incarnata, Swamp Milkweed
Swamp Milkweed occurs commonly across Kentucky in swamps, marshes, and other wet areas, especially over limestones and calcareous shale. The stems are erect to ascending, with course, petiolate leafs in an opposite arrangement. The flowers occur in flat umbels atop the stem, with vibrant pink flowers that have a fragrance similar to cinnamon.
To learn about planting Swamp Milkweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-incarnata/
Asclepias perennis, Aquatic Milkweed
Aquatic Milkweed occurs commonly in the Coastal Plain of Kentucky, occurring in cypress-gum swamps, bottomland hardwood forests, and marshes. The stems are erect, with short petioled leaves in an opposite arrangement. Flowers occur in flat umbels atop the stem or in the axils, with white to pale pink coloration.
To learn about planting Aquatic Milkweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-perennis/
Asclepias purpurascens, Purple Milkweed (State Special Concern)
Purple Milkweed is a State Special Concern milkweed that occurs throughout Kentucky in openings in moist bottomlands and swamp forests, prairies and woodlands. The steams are erect, with large opposite leaves up to 6 inches long. Deep purple flowers occur in relatively dense rounded umbels, with up to 6 umbels occurring terminally on the stem.
Asclepias quadrifolia, Four-leaf Milkweed
Four-leaf Milkweed occurs commonly in the Interior Low Plateau and Appalachian Plateau of Kentucky in moist forest and forest margins. This species has erect stems with both mid-stem whorled leaves and opposite leaves. The small pink and white flowers occur in umbels atop the stem, with relatively few flowers per umbel.
Asclepias syriaca, Common Milkweed
Common Milkweed, as its name implies, is common throughout Kentucky in pastures, roadsides and disturbed areas. This tall milkweed has stout erect stems, with large sessile leaves in an opposite arrangement. The flowers occur in large dense umbels of pink to purple flowers, with an attractive fragrance.
To learn about planting Common Milkweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-syriaca/
Asclepias tuberosa var. tuberosa, Butterflyweed
Butterflyweed is a species of milkweed that occurs across Kentucky in woodland margins, roadsides and pastures. This species can be easily identified by its vibrant orange flowers, which occur in terminal clusters. The stems are erect to ascending, with sessile to short petiolate leaves in an opposite arrangement. Unlike other milkweeds, Butterflyweed does not have milky sap.
To learn about planting Buterflyweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-tuberosa/
Asclepias variegata, Redring Milkweed
Redring Milkweed is an uncommon species that occurs across Kentucky in upland forests and woodlands. This species has a single narrow stem, with petiolate leaves in an opposite arrangement. The flowers occur in spherical umbels, with white flowers with a red ring around the middle, giving it it’s common name.
To learn about planting Redring Milkweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-variegata/
Asclepias verticillata, Whorled Milkweed
The Whorled Milkweed is an uncommon milkweed that occurs across Kentucky in barrens, thin soils of rock outcrops, open woodlands, pine flatwoods, and road and powerline right-of-ways. This species has erect stems with sessile, linear leafs in a whorled arrangement. The fragrant greenish white flowers occur in umbellate cymes in the upper leaf axils and stem ends.
To learn about planting Whorled Milkweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-verticillata/
Asclepias viridiflora, Green Milkweed
The Green Milkweed is an uncommon milkweed that occurs across Kentucky in open woodlands, woodland edges, barrens, glades, and disturbed areas. This species has an erect stem with elliptical leaves in an opposite arrangement. Pale green flower clusters occur in the upper leaf axils of the plant.
Asclepias viridis, Spider Milkweed
Spider Milkweed occurs across Kentucky and occurs in prairies, dry woodlands, calcareous hammocks, and pine rocklands. The stems are ascending, with course textured leaves with short petioles in alternate to sub-opposite arrangement. The large flowers are green, purple and white, without horns, occurring in a solitary umbel atop the stem.
To learn about planting Spider Milkweed, visit: https://monarchwatch.org/bring-back-the-monarchs/milkweed/milkweed-profiles/asclepias-viridis/