Jennifer is an environmentalist from Ohio. She is passionate about advocating for the planet and wildlife through gardening and education.
Why is Milkweed Important?
Milkweed is a very important part of Ohio’s native ecosystem. It is critically important for Monarch butterflies, whose population have been in severe decline in recent years due to habitat loss from urban development, agriculture, and pesticide use. Monarch caterpillars rely on milkweed as their one and only food source, so this is where adult female monarch butterflies lay their eggs.
There is an interesting reason for why monarch butterflies evolved to rely on milkweed plants at the beginning of their lifecycle. While the milky white sap of milkweed plants is toxic to most other animals and insects, monarch butterflies have evolved to use this toxic sap as a food source. This allows the caterpillars to incorporate milkweed toxins into their bodies as a natural defense mechanism against would-be predators. By ingesting this toxic sap, monarch butterflies and caterpillars become poisonous to birds and other predators that would otherwise threaten their survival.
Common Milkweed (Asclepias syriaca)
As the name suggests, common milkweed is one of the most common types of milkweeds found in Ohio. It can be found throughout the entire state. Common milkweed grows to four to five feet in height and has large pink, white and green flowers that bloom from mid-June through August. This milkweed species can be found growing in almost any type of open, in disturbed habitat throughout the state of Ohio (and much of the United States), including meadows, roadsides, and riverbanks.
Though some gardeners consider common milkweed an aggressive weed, it is an important food source for monarch butterflies and is an important part of Ohio’s ecosystem, so you may want to consider allowing it to grow.
Swamp Milkweed (Asclepias incarnata)
Swamp milkweed is one of the most common types of milkweeds found in Ohio, and it is one of my favorites! This tall milkweed plant features attractive bright pink flowers that bloom in July and August.
As the name suggests, swamp milkweed prefers wet soil and can commonly be found growing in marshy areas and along just about any waterway. It can be grown in average garden soil, as long as it isn’t allowed to dry out.
Butterfly Weed (Asclepias tuberosa L.)
Butterfly weed is also commonly known as Orange Milkweed or Butterfly Milkweed and is another very common type of milkweed in Ohio. This unique species of milkweed features orange, or occasionally yellow, flowers and is the only milkweed native to Ohio to have flowers this hue.
Also unique to this variety of milkweed is its clear sap. Most species of milkweed have milky white sap due to their high levels of latex, but Butterfly weed has lower latex levels, giving it a more clear-colored sap.
Butterfly weed can be found growing in many different open habitats, including dry fields and roadsides. It can even be found is disturbed or degraded ecosystems.
Purple Milkweed (Asclepias purpurascens)
Purple milkweed is a relatively common milkweed species with deep purple flowers, which bloom from late May into July. This type of milkweed looks very similar to common milkweed, but its flowers are a much deeper purple color.
Purple milkweed is found mainly in the south-central part of the state, but occasionally occurs in other parts of Ohio. It is adaptable and a bit more tolerant of shade than many other milkweed species. It can be found growing in open woods, in thickets, and along roadsides.
Four-leaved Milkweed (Asclepias quadrifolia)
The four-leaved milkweed is one of the smallest milkweeds occurring in the state. It is also one of the earliest to bloom, showing off its light pink flowers from mid-May through June. Unsurprisingly based on its name, the lower leaves of four-leaved milkweed plants tend to form a whorl of four leaves.
This species is frequently encounter throughout Ohio. It can most commonly be found in the southern and eastern parts of the state near woodlands and forests.
Poke Milkweed (Asclepias exaltata)
Poke milkweed is a milkweed species with green and white flowers that bloom from late May through June. This plant can grow to be over four feet tall. Poke milkweed is one of the most shade tolerant types of milkweed and tends to grow in woodland environments. It is one of the few milkweeds that can tolerate full-shade conditions.
Poke milkweed is found mainly in the eastern and south-eastern regions of the state but can be found scattered throughout other areas of Ohio.
Whorled Milkweed (Asclepias verticillata)
Whorled milkweed is a less common milkweed species in Ohio. Whorled milkweed has small, off-white flowers that bloom from July into September. This species gets its name from its thin, needle-like leaves that form in a whorled pattern around its stem.
Whorled milkweed is more common is states further west but can naturally occur scattered throughout Ohio. This species prefers to grow in dry, sunny conditions.
Sullivant's Milkweed (Asclepias sullivantii)
Sullivant’s milkweed is an uncommon milkweed species in Ohio. It has bubblegum-pink flowers that bloom from late June into August and looks similar to purple milkweed and common milkweed. This milkweed species was named after the great Ohio botanist and bryologist William Starling Sullivant.
Sullivant’s milkweed only grows in tall grass prairies. It can be found in prairie environments throughout central, north central, and northwest Ohio.
White Milkweed (Asclepias variegata)
Another rather uncommon milkweed species found in Ohio, white milkweed features snow-white flowers that bloom from late May through June.
Within the state, White milkweed is only found in is south-central Ohio. It grows in dry, rocky woodlands, along roadsides, and in thickets throughout this region.
Green-flowered Milkweed (Asclepias viridiflora)
Green-flowered milkweed, or short green milkweed, is another uncommon milkweed species found in Ohio. This small variety of milkweed has green flowers and blooms from late June into August.
Green-flowered milkweed occurs randomly throughout the state and prefers dry, open areas. It seems to occur most commonly in the limestone barrens and prairies of Adams County.
Spider Milkweed (Asclepias viridis)
Spider milkweed, also known as green antelope-horn milkweed, is a short species of milkweed with large, showy green flowers that bloom from mid-May to mid-June.
This uncommon milkweed species is found in Ohio only in the most southern part of the state in Adams County. It can be found growing in dry areas, particularly prairies.
Clasping Milkweed (Asclepias amplexicaulis)
Clasping milkweed is also called blunt-leaved milkweed. This uncommon species is of the earliest blooming species in Ohio, featuring wine-red to yellowish flowers. It can grow between two and four feet tall and has distinctive clasping leaves.
In Ohio, this milkweed species grows in the northwest corner and the south-central/southeastern areas of the state. It prefers dry, open environments.
Tall Green Milkweed (Asclepias hirtella)
Another uncommon species in Ohio, tall green milkweed, also known as prairie milkweed, has small greenish-yellow flowers, which usually bloom from late June into August. A very, very similar-looking milkweed known as the longleaf milkweed (A. longifolia) exists in the Atlantic coastal plain and Gulf states, and it is debated as to whether these two milkweeds are subspecies or separate species altogether.
Tall green milkweed can be found in the southeast and northwest parts of the state, in the same areas where clasping milkweed is found. It is typically found in damp fields, prairies, and along roadsides.
- Milkweed Profiles | Bring Back The Monarchs
- The Buckeye Botanist: A Guide to the Milkweeds of Ohio
- Stunning Ohio Wildflowers to Find in Summer
Spring may get a lot of attention, but summer in Ohio has some amazing native wildflowers all season long. Explore a few and learn where you might find them.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Jennifer Wilber