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

Milkweed

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Lmmahood/Getty Images
Botanical Name
Asclepias spp.
Plant Type
Sun Exposure
Bloom Time
Flower Color
Hardiness Zone
Special Features
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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.
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