Plant This!
Milkweed | Asclepias
Milkweeds aren’t a Weed!
When I was a little girl growing up in Texas, I walked to and from school every day. One day on my walk home, I noticed a tree in my neighbor's yard. It looked strange. Like the tree had died overnight. But it was also flickering, pulsing. And then I realized that that tree was covered with Monarch Butterflies – thousands of them, hanging from the limbs, wings down. I stood there, watching the tree for a very long time. And I have never seen such a sight again.
Those Monarchs were on their miraculous migration from parts all over North America to Mexico in the fall and back across the continent all the way to Canada in the spring. Their migration is treacherous, but these delicate flyers make it twice each year. And they are the only butterfly species in the world to migrate long-distance.
But it isn't the migration that is leading to their decline in numbers. It is a lack of one plant group: Milkweed.
Monarch Butterflies depend on Milkweed – and only the native North American milkweeds – for their lifecycle. The dramatic decline in Monarch Butterflies means few children will have the opportunity to see what I saw that fleeting day long ago. The Monarch is now destined to be listed as threatened on the Endangered Species list this year, assuming the present regime doesn't gut the Endangered Species Act.
But as with so many other problems, we can help the Monarch Butterflies with a relatively simple act: planting native Milkweeds in abundance!
What Is Milkweed and Why Is It Important?
Milkweed (Asclepias spp.) refers to a group of flowering plants native to North America that play a critical role in the health of ecosystems. Best known as the exclusive host plant for the iconic Monarch Butterfly (Danaus plexippus), milkweed is far more than just a butterfly plant—it's a biodiversity powerhouse that supports pollinators, enriches soil health, and enhances native habitats.
Milkweed species all have a milky-white latex in the leaves and stems which is toxic to most other animals. The Monarch Butterfly and its caterpillars have evolved to be immune to this poison, so the caterpillars eat the leaves of the milkweed and become toxic themselves which saves them from predators. Kinda amazing!
The butterfly only lays eggs on Milkweed because the Milkweed is the only plant the Monarch caterpillars can eat. The caterpillars eat the Milkweed leaves – and won't munch on anything else in your garden. The Monarch Butterflies themselves enjoy the nectar-rich blooms of the Milkweed, but they also drink from other flowers, too.
So the plants and the butterflies have coevolved over millions of years, and the butterflies rely on Milkweed plants to survive from the egg stage of their life onward.
Inside the Monarch Butterfly Migration
with Anderson Cooper
Key Native Milkweed Species in North America
So, what milkweed should you plant? Well, that depends on where you live in North America. There are over 100 species of milkweed native to North America, each adapted to specific climates and regions. And you will know it is a native milkweed if the Latin name for the species starts with Asclepias.
Here are some of the most commonly available species:
Common Milkweed (Asclepias syriaca)
Habitat: Fields, roadsides, and open woodlands across the Eastern and Midwestern U.S.
Ecological role: A primary host for Monarch butterflies and a nectar source for bees and wasps.
Butterfly Weed (Asclepias tuberosa)
Habitat: Prairies and dry, sandy soils.
Ecological role: Its bright orange flowers attract bees, butterflies, and other beneficial insects.
Swamp Milkweed (Asclepias incarnata)
Habitat: Wetlands, ditches, and stream edges.
Ecological role: Supports Monarchs and serves as a pollinator magnet in moist environments.
Showy Milkweed (Asclepias speciosa)
Habitat: Western North America, from California to the Midwest.
Ecological role: Offers a vital breeding ground for Monarchs in western migration corridors.
Antelope Horns (Asclepias asperula)
Habitat: Arid regions of the Southwest and Texas.
Ecological role: One of the few milkweeds adapted to dry, desert-like conditions—crucial for local pollinators.
To find the Milkweed species that's best for your location, check out the Xerces Society's Milkweed Finder tool!
Showy Milkweed (Asclepias speciosa) in my garden.
A Monarch on Asclepias tuberosa.
Asclepias tuberosa in my garden.
How to Grow Milkweed in Your Garden
These are very generalized instructions. Tailor your approach depending on which varieties you are growing.
How to Grow Milkweed from Seed
Cold Stratification: after you buy seeds, you will need to cold stratify them before they will grow.
Place the seeds in a mixture of damp coco coir in a ziploc bag. Let all of the air out of the bag, and seal it tightly.
Place the bag in the refrigerator for 1-3 months.
Planting the Seeds:
Once the seeds have been cold stratified, you can either:Plant the seeds outside (do this December - February).
Start the seeds inside in seed trays.
Plant 3-4 seeds per cell.
Cover with ¼ in. of vermiculite.
Place under grow lights and on a heat mat.
Bottom water. Keep the soil moist but not wet.
Harden off when the plants have at least 4 true leaves.
Plant out into the garden in a sunny position, 1-2 feet apart.
Showy Milkweed in the fall as the seedpods develop.
How to Grow Milkweed from Plugs
There are several reputable sources where you can purchase Milkweed plugs. Look for varieties which are native to your part of North America.
Recommended sources:
High Country Gardens: has a wide variety of species available (Discount code: MDRNMAMA for $5 off orders of $50 or more.)
Izel Plants: a great source for people on the East Coast
Prairie Moon Nursery: sells both seed and plugs
Your native plant society
Your local botanical gardens
Check the Directory from Homegrown National Park
Tips for Growing Milkweed Plugs:
Plant in the spring or in the fall for best results.
Plant in full sun or part-shade depending on the species.
Water frequently for the first two years. While most Milkweeds are perennial and many varieties are waterwise, they can be slow to establish and need additional watering and support for the first few years.
Plant multiple varieties and at least three plants of each in the same location for a true pollinator feast!
Why Milkweed Matters:
4 Ecological Benefits
1. Monarch Butterfly Habitat
Milkweed is the only plant genus on which Monarch butterflies lay their eggs. The larvae feed exclusively on milkweed leaves, making it essential for Monarch reproduction and survival.
Hot Tip: Also plant some Asters and Solidagos along with your Milkweed for late-fall feasting as Monarchs head south for the winter!
2. Pollinator Support
Milkweed flowers are rich in nectar and attract a wide array of pollinators—including bees, wasps, beetles, and hummingbirds. Different milkweed species bloom at different times, providing a continuous food source throughout the growing season.
3. Biodiversity Enhancement
Native milkweeds support complex food webs, offering shelter and resources to insects, birds, and small mammals. Their presence increases the resilience of ecosystems and improves overall biodiversity.
4. Soil and Water Benefits
Many milkweed species help stabilize soil with deep taproots, reduce erosion, and improve water infiltration, especially in prairie and riparian areas.
Don’t Freak Out about Aphids on your Milkweed!
Threats to Milkweed and How to Help
Urban development, pesticide and herbicide use, and habitat fragmentation have led to a steep decline in native milkweed populations—along with the Monarch butterflies that depend on them.
What You Can Do:
Plant native milkweed: Choose species appropriate for your region to ensure ecological compatibility.
Don't use pesticides or herbicides: insecticides and herbicides can harm milkweed plants and their pollinators.
Watch out for native patches of milkweed and work with local governments to preserve them – and to encourage more planting of milkweed in drainage ditches, on organic farmland, in public parks and open spaces, and in hellstrips.
Support conservation efforts: Donate to or volunteer with organizations that promote native plant restoration.
Milkweed Is More Than a Monarch Plant
Milkweeds are foundational to healthy ecosystems across North America. Whether you're a gardener, a conservationist, or a nature lover, planting and protecting native milkweed species is a simple yet powerful way to support biodiversity, pollinators, and ecological resilience.
If you have questions, just ask! And be sure to sign up for my Substack where you’ll get gardening goodness right in your email box!