Planting, Growing, and Caring for Milkweed
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Milkweed (Asclepias) is a native wildflower we should all grow for the butterflies—specifically monarchs! The Old Farmer’s Almanac will help you choose your milkweed plants, explain when and how to plant, and instruct you on after-season care.
About Milkweed
Several popular species are suited for cultivation in the garden. Common milkweed (Asclepias syriaca) is the best-known of the over 100 perennial milkweeds native to North America. Milkweed plants support 12 species of butterflies and moths, including the monarch butterfly.
The nectar in all milkweed flowers provides valuable food for butterflies, bees, and other pollinators. Butterflies need not only nectar but also food at the caterpillar stage. The leaves of milkweed plants are the only food monarch caterpillars can eat. Monarch butterflies also need the milkweed plant to lay their eggs on.
Growing
How to Grow Milkweed
Do not worry if the plants take time to get going. They stay dormant longer than most plants but should start leafing out in late spring or early summer. Avoid watering during dormancy. If they don’t flower in the first season, their leaves still provide a food source for monarch babies.
- Common Milkweed and Butterfly Weed need little water and thrive in a drier environment. Swamp and Tropical Milkweed need to be watered but not overwatered
- Water plants if the soil is dry, but avoid overwatering (especially during early dormancy).
- The good news is that milkweed is otherwise left alone. Do NOT fertilize, spray, or prune.
- Common milkweed (Asclepias syriaca) is a hardy perennial that will thrive almost anywhere in the United States, especially east of the Rockies and into Canada. It needs sun, reaches 2 to 6 feet tall with wide gray-green velvety leaves, and is an aggressive grower. Don’t plant this in your flowerbed or it will take over. It has a wide-spreading root system and needs an area all its own where it can really stretch out. It has pale purple-pink flowers that are very fragrant and attract many pollinators in addition to monarch butterflies.
- Butterfly weed (A. tuberosa) is less aggressive than the common milkweed, growing only 1 to 2-1/2 feet tall. It is commonly grown in gardens, adapts well to moist or dry soil, and has very showy orange flowers. It likes full sun and is hardy in Zones 3 to 9.
- Swamp milkweed (A. incarnata) has thinner leaves and more colorful flowers than common milkweed. It is better-behaved than common milkweed, forming clumps rather than spreading out. It grows 2 to 4 feet tall, has deep rose-pink flowers, and is shade tolerant. It will grow in wet soil near lakesides or damp marshlands but also grows well in average garden soil and is hardy in Zones 3-9.
- Showy milkweed (A. speciosa) is native from west of the Mississippi into California and north to Canada. It has pastel pink flowers on 2- to 4-foot-tall plants. It is drought tolerant, making it a good plant for arid plains and prairie-lands, though it grows well in moist garden soils as well. It needs full sun and is hardy in Zones 3-9.
Wit and Wisdom
- The genus name, Asclepias, commemorates Asklepios, the Greek god of medicine.
- Native Americans taught early European settlers how to cook milkweed so that it could be safely eaten.
- The milky white sap was applied topically to remove warts, and the roots were chewed to cure dysentery.
- Infusions of the roots and leaves were taken to suppress coughs and used to treat typhus fever and asthma.
- The stems’ tough, stringy fibers were twisted into strong twine and rope or woven into coarse fabric.
- Inside milkweed’s seed pods is fluffy white floss attached to brown seeds. The floss was used to stuff pillows, mattresses, and quilts and was carried as tinder to start fires.
- Milkweed is the state wildflower of Illinois.
- During World War II, the regular material used to stuff life jackets was in short supply, so milkweed floss was used as a substitute—it is about six times more buoyant than cork.
- See more uses and natural remedies for milkweed.
Catherine Boeckmann
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I live on Long Beach Island in NJ USA. I want to plant milkweed on the sand dunes. We are on the monarch route. How do I plant in sand?
Hi Peggy,
While common milkweed does perform well in sandy soils and poor soils, it does need soil in order to thrive. If you do want to plant milkweed for migrating monarchs, you could do so in some containers.
There is a variety of milkweed, sandhill milkweed, that can be planted in sand dunes, but it is native to the southeast and only winter hardy in Zones 8 and 9.
Thank you. This information helps.
I had a few "freebie" common milkweed plants pop up in my small round swamp milkweed garden this spring. So I let them grow. (all for the love of Monarchs, right?) Anyhoo, boy did they grow. They're way taller than me now! When in bloom they attracted bumblebees, honeybees, butterflies, etc. However, to my dismay, I noticed honeybees dead (quite a few of them) on the flowerheads. I KNEW they were not subjected to any poisons so I reached out to my local conservation dept. I was told that it is quite common for the honeybee's feet to become trapped in the flower. They cannot get their feet out, then starve to death! I thought OMG, how horrible! I will be taking out/perhaps transplanting the common milkweeds elsewhere (somewhere that I cannot see the dead honeybees next season) because not only does it break my heart to see them dead on the flowerheads, the common milkweed has pretty much shaded and took over my small pollinator garden. The conservation dept. told me that this does not contribute to the honeybee's decline, but it sure is upsetting to see the dead bees!
I planted some common milkweed in my flower beds. YIKES. I didn't know they were so invasive. I do not want them in my flower bed because the roots spread underground and they pop up every where. I dug up alot of them last year, bur they keep popping up everywhere in my flower bed. HOW I do I get them completely out of my flower beds?
We put a milkweed plant in our flowerbed for the first time this year. The branches to the plant are bowing out a lot. I am wondering if I should bring them back in toward the center stem with some twine and use a dowel rod to stabilize it?
Thank you!
I have had to stake ALL of my milkweeds. Common and swamp both.
Hi Teri-
The milkweed will be healthy if it bows, but if you prefer to have it upright, please go ahead and stake it.
Thanks!
Unfortunately, I planted a milkweed in a small bed next to my porch. It is too large and I want to move it out to my creek bed, the ideal place to grow as large as it can. How do I transplant a full-grown plant? And the leaves are mottled brown instead of a nice green color - what do I treat with to restore plant to good health?
Carefully dig around the base of the plant, starting 7-8 inches out from the stems. You’ll want to capture as much of the root ball as possible, so dig carefully. Once you’ve loosened the plant, carefully lift it, retaining as much of the root ball and soil as you can. Plant it in its new home and water well. If rains are infrequent, be sure to keep the plant watered until hard frosts set in.
It’s possible that the browned leaves are simply a symptom of drought or the end of the growing season, so just keep an eye on it when it pops up in the spring to see if the foliage looks as it should.
