“What types of milkweed should I plant in my garden?”
This may seem like a crazy question if you’re just getting started with native gardening. Why would you want to plant a weed?!
But milkweed isn’t a weed at all. Instead, it’s a flowering plant that attracts butterflies (think Monarchs), native bees, and other pollinating insects, which is an excellent thing!
This article will give you information about common types of milkweed in your area and which ones will be best for your garden. And, keep reading to the end to learn about a kind of milkweed you want to avoid!
4 Types of Milkweed in Wyoming:
#1. Green Comet Milkweed
- Asclepias viridiflora
- USDA Hardiness Zone: 3-10
- Life Cycle: Perennial
- Approximate Mature Size: 1.5 to 2 feet
- Bloom Time: June to September
Green Comet Milkweed flower clusters form in the pocket created by the upper leaves. They’re made up of 20 to 80 small, pale green flowers. Interestingly, the yellowish-green leaves of this species vary in shape depending upon their habitat. Plants from moist sites tend to have rounder leaves, while plants from dry sites have long, narrow leaves.
In the wild, this species is often found on shaded roadsides, savannas, and prairies with moist to dry soil. In the garden, you can grow Green Comet Milkweed from seeds. It grows best in light to moderate shade but will tolerate full sun. Medium-dry to dry soil is best. Green Comet Milkweed doesn’t need rich soil and will tolerate sandy or rocky soil with low organic matter.
This species is a good choice for low-maintenance gardens as its long taproot allows it to tolerate drought well. Unlike many other milkweeds, this species is easy to prevent from spreading. It doesn’t form the large colonies typical to other milkweeds, so it’s an excellent option for smaller gardens!
The Green Comet Milkweed’s copious nectar and sweet fragrance attract many pollinators, including honeybees, native bees, and butterflies. It’s also a host plant for Monarch Butterflies, though it can be more challenging for monarchs to find because of its scarcity and preference for partial shade.
#2. Showy Milkweed
- Asclepias speciosa
- USDA Hardiness Zone: 3-8
- Life Cycle: Perennial
- Approximate Mature Size: 1.5 to 3 feet; occasionally up to 6 feet
- Bloom Time: May to September
As the name suggests, Showy Milkweed features flashy pink and white umbels or clusters of small flowers. The flowers are fragrant, and individual flowers look a bit like crowns. In ideal conditions, Showy Milkweed may grow as tall as 6 feet!
As a garden plant, Showy Milkweed has the benefit of being a less aggressive spreader than most other milkweed varieties in Wyoming. It can be grown easily from seed or the cuttings of an existing plant. It’s very drought tolerant and can be grown in a wide range of soils.
Like other milkweeds, Showy Milkweed attracts native insects and Monarch Butterflies to your yard or garden. Monarchs will visit the flowers for nectar and lay eggs on the plants, which are host plants for the Monarch caterpillars. It will also attract beautiful Queen and Viceroy butterflies to your property!
#3. Humboldt Mountain Milkweed
- Asclepias cryptoceras
In addition to Humboldt Mountain Milkweed, you may hear this species called Phallid Milkweed, Jewel Milkweed, Prostrate Milkweed, or Cow-Cabbage. Some of these names reflect its unusual appearance. 🙂
Humboldt Mountain Milkweed is a low-growing or drooping perennial with large, thick, heart-shaped, cabbage-like leaves. The flower clusters at the top of the stem look like jewels in the desert. Look for flowers that feature rose-colored hoods and white or yellowish-green petals that are bent downward. You may spot this plant blooming between April and June.
Humboldt Mountain Milkweed grows best in Wyoming in areas with full sun and dry rocky or sandy soil. You can find it on talus slopes, roadsides, canyon bottoms, arid plains, and sandy and rocky washes.
#4. Plains Milkweed
- Asclepias pumila
This little milkweed is a creeping perennial that usually grows less than a foot tall. At first glance, Plains Milkweed may look more like rosemary than milkweed! It has small, thin, linear, whorled, or dense alternately-arranged leaves growing up its stems.
Look for Plains Milkweed in Wyoming in dry, rocky, or sandy prairies or grasslands. Between July and September, globe-shaped clusters of small pink-to-white flowers form at the tip of each stem and sometimes in the axils of the upper leaves.
In addition to being a larval host plant for Monarch, Queen, and Soldier Butterflies, Plains Milkweed is also an important nectar source for various moths and butterflies, including Clarks Sphinx Moths, Milkweed Tussock Moths, Carus Skippers, Eastern Tiger Swallowtails, and Falcate Metalmark Butterflies.
- Asclepias curassavica
- USDA Hardiness Zone: 8-11
- Life Cycle: Perennial
- Approximate Mature Size: 3 to 4 feet
- Bloom Time: March to November in temperate climates, year-round in tropical climates.
This non-native milkweed plant has become popular in recent years because of its flowers’ bright red coloring and how easy it is to plant and maintain.
Unfortunately, Tropical Milkweed planted in Wyoming may do more harm than good.
It carries a parasite of Monarch Butterflies called Ophryocystis elektroscirrha, or OE, which can cause defects in the wings of Monarchs. Since it doesn’t die back and can bloom late, the plant itself may also confuse Monarchs by signaling a breeding season when it’s time to migrate.
To ensure you’re planting milkweed that will help your local ecosystem and attract native pollinators, always choose a native species!
Marketers of Tropical Milkweed seeds will use the names Mexican Milkweed, Bloodflower, Mexican Butterfly Weed, Mexican Orange Milkweed, and Semi-Tropical Milkweed. Steer clear of all of these!
Are you looking for more information on milkweed in Wyoming?
Check out this guide!
Do you have milkweed in your garden?
What’s your favorite thing about this plant? Leave a comment below!