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

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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

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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

Linda Shaw (not verified)

3 months 2 weeks ago

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.

Rose (not verified)

4 months 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)

6 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.