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Milkweed: How to Plant and Grow Milkweed Flowers | The Old Farmer's Almanac

Milkweed

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

How to Plant and Grow Milkweed

The Editors
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Milkweed is a native wildflower beloved by monarch butterflies. There are a number of popular species suited for cultivation in the garden. Here’s how to plant, grow, and care for milkweed in your garden—and support butterflies!

About Milkweed

Common milkweed (Asclepias syriaca) is the best known species of the over 100 perennial milkweed species 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 that monarch caterpillars can eat. And monarch butterflies also need the milkweed plant to lay their eggs on.

Planting

When to Plant Milkweed

  • 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. 

Choosing and Preparing a Planting Site

  • Milkweed plants require full sun and a lot of space.
  • 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.

How to Plant Milkweed

  • Scatter seeds on top of the soil and cover with about ¼ inch additional soil. 
  • Seeds will germinate in 7-10 days.
  • Thin seedlings to 2 inches apart.
  • Transplant seedlings when 3-6 inches tall.
  • Plant transplants in blocks rather than long rows. Plant milkweed 18-24 inches apart.
  • Water after planting and keep soil moist until plant are established.
  • Add mulch around the plants to keep the soil moist and discourage weeds.
Growing

How to Grow Milkweed

  • Water plants if soil is dry, but avoid overwatering.
  • Plants generally do not need supplemental fertilization.
  • Avoid using insecticides/herbicides in areas around milkweed.
  • Plants may not bloom the first year, but leaves will still provide a food source for butterfly caterpillars.
"Butterfly weed"
Butterfly weed, Asclepias tuberosa. Photo by NNehring/Getty Images.
Recommended Varieties
  • 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

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. 
Wit and Wisdom
  • The genus name, Asclepias, commemorates Asklepios, the Greek god of medicine.
  • Native Americans taught early European settlers how to properly 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 seedpods"
Milkweed seed pods
Pests/Diseases
  • Aphids
  • Milkweed leaf beetle
  • Milkweed tussock moth
  • Red and black milkweed bugs
  • Leaf spot
  • Root rot
  • Verticillium wilt

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Comments

Christine Santee (not verified)

5 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)

5 months ago

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

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.

You can find milkweed seeds on a number of seed-selling websites, or you may be able to find them at your local nursery. You should also be able to find young plants at nurseries. 

We wouldn’t recommend taking milkweed from the wild, as it should be left in its natural habitat! It also may be illegal in some places. If you happen to have a friend with milkweed on their property, perhaps they could give you some seeds at the end of the season.