Table of Contents for Oval-leaf Milkweed (Asclepias ovalifolia)
Introduction
Oval-leaf Milkweed (Asclepias ovalifolia) is a herbaceous perennial found in the northern parts of the midwest United States and Canada from British Columbia to Ontario. This plant grows in prairies, open woods, and roadsides that have sandy soil and is a host for the Monarch Butterfly (Danaus plexippus). The white, green to pink tinged flowers come out in the late spring to summer.
Taxonomy and Naming of Oval-leaf Milkweed (Asclepias ovalifolia)
Taxonomy
Oval-leaf Milkweed (Asclepias ovalifolia) was described and named by Joseph Decaisne, a French botanist, in 1844. It has kept the same name since. This plant is a member of the Dogbane Family (Apocynaceae).
Meaning of the Scientific and Common Names
Scientific Name
The genus name, Asclepias, is named for the Greek god of healing, Asklepios (Flora of Wisconsin). The species name, ovalifolia, is the Latin name describing the oval-shaped leaf.
Common Name and Alternative Names
The common name describes the shape of the leaves. One name – ovalleaf milkweed – is without the hyphen. Two other alternative names, dwarf milkweed and low milkweed (Macdonald 2003), describe the short stature of this milkweed.
Physical Description
Description
- Plant Type: This plant is a herbaceous rhizomatous perennial.
- Height: This plant grows to about 2 feet tall.
- Leaves: This leaves are opposite, simple, entire, and lanceolate, elliptic to broadly ovate to oval shaped. They range from 2 to 4 inches in length and 0.75 to 1.75 inches in width. The petioles are short and may be almost sub-sessile and the leaf tips can sometimes be mucronate.
- Flower color: The flowers are white, pinkish, or green with a purplish tinge.
- Blooming period: This plant blooms from May to August, depending on location.
- Fruit type and period: This plant has follicles that mature in the late summer.
Range of Oval-leaf Milkweed (Asclepias ovalifolia) in the United States and Canada
Range
This species is located in the mid-western United States from Michigan to Montana. In Canada it extends from Ontario to British Columbia. It is considered to be rare in the states of Illinois, Wisconsin, Michigan, and Montana. In Canada it is rare in Ontario.
Habitat
This milkweed grows in open areas such as tallgrass prairies on slopes (Caitling and Kostiuk 2006), grasslands and savannas (Timoney and Robinson 1998), alluvial terraces (Vanderhorst and Cooper 1998), railroad edges (Woodson 1954), edges, and barrens and open woodlands where it can receive full sunlight or partial shade.
Insects and Other Wildlife it Supports
Host Species
This plant is a host to the Monarch Butterfly (Danaus plexippus).
Other Supported Wildlife
This plant is used as a nectar plant for many other insects including bees and flies. Goldfinch use the hairs of the seeds to build nests (Illinois Wildflowers).
Frequently Asked Questions
Is this plant poisonous?
Like other milkweeds, this plant has cardiac glycosides (cardenolides), which are poisonous with ingestion to both humans, livestock, and pets.
What other milkweeds are similar to this one?
The flowers of this milkweed are similar to the common milkweed (Asclepias syriaca), though the common milkweed flowers are somewhat bigger. This milkweed is also similar to showy milkweed (Asclepias speciosa), but differs from it in having pubescent and pointed leaves (Macdonald 2003). Having green flowers, this milkweed is similar to green comet milkweed (Asclepias viridiflora) and narrow-leaf milkweed (Asclepias stenophylla), but neither have a horn structure in the flower (Macdonald 2003 and Heidel and Dueholm 1995). Oval-leaf milkweed is distinguished from most other milkweeds by its thin stem and soft pubescent leaf blades (AAA). Most other milkweeds have a thicker stem. The distinctive thinness of the stem can be seen in the herbarium specimen above.
Are there any ethnobotanical uses of this plant?
This species is not addressed specifically in the Native American Ethonobotany Database, but uses of other milkweeds include medicines, fibers, and foods.
Gardening with Oval-leaf Milkweed (Asclepias ovalifolia)
Hardiness
This plant species is hardy in zones 5-9. If your garden is within these zones and you have the right soil and exposure, you may be able to grow this species in your garden. The hosted species, the Monarch Butterfly and the Queen Butterfly are widespread and may very well be present in your area.
Optimal Conditions
This plant likes places with full sunlight or partial shade and well-drained soil that tends towards a higher pH.
References
- Heidel, Bonnie L. and Keith H. Dueholm. 1995. Sensitive plant survey in the Sioux District, Custer National Forest, Carter County, Montana, and Harding County, South Dakota. Helena, Montana: Montana Natural Heritage Program.
- Macdonald, Ian D. 2003. A rare plant survey of the Wainwright Dunes Ecological Reserve. Edmonton, Alberta: Alberta Sustainable Resource Development.
- Caitling, Paul M. and Brenda Kostiuk. 2006. Tallgrass Prairie in the Whitewood Area of Saskatchewan. Blue Jay 64: 72-83.
- Timoney, Kevin and Anne Robinson. 1998. A floristic and landscape survey of the Ft. Assiniboine Sandhills Wildland Park. Sherwood Park Alta, Treeline Ecological Research.
- Vanderhorst, James P. and Stephen V. Cooper. 1998. Botanical and vegetation survey of Carter County, Montana, Bureau of Land Management-administered lands. Helena, MT: Montana Natural Heritage Program.
- Woodson, Robert E. 1954. The North American Species of Asclepias L. Annals of the Missouri Botanical Garden 41: 1-211.