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How to Grow Milkweed: The Complete Plant Guide

Photo Credit
Lmmahood/Getty Images
Botanical Name
Asclepias spp.
Plant Type
Flower
Sun Exposure
Full Sun
Soil pH
Slightly Acidic to Neutral
Bloom Time
Spring
Summer
Flower Color
Orange
Pink
Purple
White
Hardiness Zone
3
4
5
6
7
8
9
Special Features
Attracts Butterflies

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Planting, Growing, and Caring for Milkweed

Catherine Boeckmann

Milkweed (Asclepias) is a native wildflower we should all grow for the butterflies—specifically Monarchs! The Old Farmer’s ÃÛÌÒÁµÈË 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 don’t only need nectar but also need food at the caterpillar stage. The leaves of milkweed plants are the only food monarch caterpillars can eat. Plus, monarch butterflies also need the milkweed plant to lay their eggs on.

Self-sowing milkweed before flowering! Credit: Catherine Boeckmann
Read Next

Planting

When to Plant 

  • Milkweed can be grown from seed or transplants.
  • Start seeds indoors about 4 to 8 weeks before your last frost date in the spring.
  • Alternatively, sow seeds directly into the garden soil in the fall or in early spring. 

Where to Plant

  • Milkweed plants require full sun.
  • Milkweed does best in well-draining soil, although some species, like swamp milkweed, prefer to grow in soil with higher moisture levels.
  • Plant in the back of flower beds or create a bed for just milkweed. They can grow quite tall and need lots of space for their deep root systems to spread. They do NOT like to be transplanted.
  • Consider planting low-growing perennials 
  • Plant low-growing perennials in front of the milkweed.

How to Plant 

  • If you plant from seed, scatter seeds on top of the soil and cover with about ¼ inch of additional soil. Seeds will germinate in 7 to 10 days. Thin seedlings to 2 inches apart.
  • If you buy small plants, choose healthy specimens with well-developed root systems. Gently loosen the roots a bit before planting.
  • Plant to plant transplants in blocks rather than long rows. Space milkweed 18 to 24 inches apart.
  • Dig a hole that’s two times as deep and wide as the rootball of your plant. There is no need to amend healthy soil or amend it with a little compost.
  • Plant with the top of the root ball even with the soil line, and fill the rest of the hole with extra soil and firm up the area.
  • Water after planting to compress the soil and keep the soil moist until plants are established.

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. 
"Butterfly weed"
Butterfly weed, Asclepias tuberosa. Photo by NNehring/Getty Images.

Types

  • 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 its orange flowers are very showy. 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.

Harvesting

Once established, milkweed does NOT like to be transplanted or divided.  If possible, leave milkweed alone. 

If you are bothered by the plants’ more scraggly looks or half-eaten leaves late in the season, remember to plant them at the back of your garden (or in their own space) and low-growing perennials in the front to hide the milkweed stems.

As with many native plants, milkweed will self-seed which is a free and natural way of spreading Monarch food. If you do NOT want milkweed spreading in your garden bed OR you’d like to plant some milkweed in a different location, you can remove the seedpods (before they burst open) and scatter the seeds elsewhere. 

You can also propagate milkweed from cuttings and give the plant to friends!

Propagating Milkweed from Cuttings

  1. Cut fresh green stems (1/3 inch diameter) from young milkweed plants.
  2. Recut the stems underwater and coat the bottom of the stems with rooting hormone. 
  3. Place the stems in moist sand, vermiculite, or potting soil. 
  4. The stem cuttings will root in 6-10 weeks and will be ready to be transplanted outdoors. 
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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. 
"Milkweed seedpods"
Milkweed seed pods

Pests/Diseases

Milkweed isn’t severely affected by pests, diseases, or problems. You are most likely to see aphids enjoying the nectar! Just squirt with a water hose (but be careful to check for Monarch eggs!). 

  • Aphids
  • Milkweed leaf beetle
  • Milkweed tussock moth
  • Red and black milkweed bugs
Flowers
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s ÃÛÌÒÁµÈË found each other. She leads digital content for the ÃÛÌÒÁµÈË website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

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Comments

Rose (not verified)

2 years 1 month ago

I pick some milkweed pods from a friends pond area, back around Labor Day. Allowed them to dry out & separated from the silk. I live in Pa zone 6b, is it safe to plant the seeds at this time?

I've planted seeds in the fall & they come up earlier in the spring than if I wanted until spring to plant.

Tammi (not verified)

2 years 3 months ago

I grew several milkweed plants from seeds last year. This year they came back and brought several monarchs to my garden. I live in MA. Yesterday I discovered several monarch caterpillars. I love the orange butterfly weed and plan to plant more next year. They were easy to grow and beautiful addition to my garden.

Christine Santee (not verified)

2 years 10 months ago

I live in Oregon near the Columbia River Gorge. I have a successful garden with four raised beds plus plenty of room for flowers. I planted Orange Milkweed which thrived for the past three years but have seen no Monarch butterflies yet my garden attracts birds, bees and moths. Is Oregon in the pathway of Monarchs? I realize they've been on the decline and want to help in the solution long term. Suggestions, please.

Thanks!

Monarchs may be found in eastern Oregon in the spring and summer, but it appears that they aren’t as common in western Oregon. So, you may be just out of their natural range! The best thing you can do for your garden is to plant native plants (and native varieties) that are naturally found in your area. This will attract the wildlife you want!

Carol (not verified)

2 years 10 months ago

Do you buy milkweed seeds at feed stores? Or take them from fields and transplant

I bought my milkweed seeds from the Live Monarch website. They not only have seeds specific for certain areas, they detail how and when to plant and how to care for the caterpillars as they are growing. It’s very affordable and informative.

Hi Carol. I have lots of milkweed seeds that I collected last year. If you would like some, I’d be glad to share. No charge. I live in WV.

Hi Jill... I would LOVE some milkweed seeds. Are you willing to share with anyone or do you know Carol? :) I have a garden in my backyard that I'd love to plant some milkweed in. Please let me know! Thanks so much..

I too am in search of milkweed seeds if you have any to spare. I live near West Virginia.