How to Grow Showy Milkweed
Wikimedia Commons
Showy Milkweed
Asclepias speciosa
flowerShowy milkweed is a native North American perennial wildflower prized for its clusters of pink to deep purple fragrant flowers that bloom mid-summer. It is an essential host plant for monarch butterflies and a valuable nectar source for many pollinators. This drought-tolerant plant typically grows 2-4 feet tall and spreads via underground rhizomes.
When should you plant Showy Milkweed in your zone?
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Example Showy Milkweed timeline · Pittsburgh, PA (Zone 6b)
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Plant Showy Milkweed
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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First Showy Milkweed blooms
Mid-to-late summerBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Showy Milkweed dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9, particularly well-suited to western and transitional zones
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Germination & Seedling
3-4 weeksSeeds sprout 7-14 days after sowing. Seedlings emerge with paired cotyledons and develop true leaves gradually.
Keep soil consistently moist but not waterlogged. Provide light once seedlings emerge. Seeds benefit from 30 days cold stratification before planting.
Establishment
4-8 weeksYoung plant develops a strong root system and increases in size, growing 6-12 inches tall in the first season.
Water regularly to establish deep roots. Remove competing weeds. Do not fertilize heavily as this is a plant of lean soils.
Vegetative Growth
Throughout growing season until floweringPlant reaches full height (2-4 feet) and develops multiple stems with lance-shaped leaves arranged alternately. Rhizomes spread to form a small colony.
Allow plant to spread naturally; divide or contain if needed. Minimal supplemental water needed once established. Remove any dead or diseased stems.
Flowering
6-8 weeks, typically June-AugustDense umbel clusters of fragrant pink, rose, or purple flowers appear at stem tips. Flowers are highly attractive to monarch butterflies and other pollinators.
Do not deadhead if you want seeds and monarch caterpillar food. Allow milkweed bugs and other insects to feed; they are part of the ecosystem.
Seed Production & Dormancy
8-12 weeks; overwinters as dormant rhizomesSpent flowers develop into large, bumpy seed pods (follicles) filled with silky seeds. Plant dies back after frost in fall.
Leave seed pods on plant for monarch caterpillar food and seed dispersal. Allow self-seeding or collect pods for seed saving. Cut back dead stems in late fall or early spring.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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These are beneficial! Allow them to feed and pupate. They are not a pest but a desired visitor.
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Generally harmless; they feed on seeds and pods. Allow them as part of the ecosystem; remove only if population becomes overwhelming.
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Spray with strong water stream or use insecticidal soap if necessary. Avoid broad-spectrum insecticides that harm pollinators.
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Increase humidity; spray with water. Use neem oil only as a last resort.
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Ensure good air circulation. Remove affected leaves. Avoid overhead watering. Severe cases: treat with sulfur dust or fungicide.
Uses
Monarch butterfly host plant
WildlifeShowy milkweed is an essential host plant for monarch butterfly caterpillars, which feed exclusively on milkweed species. A single plant can support dozens of caterpillars through their development to chrysalis. [source]
Pollinator nectar source
WildlifeThe abundant fragrant flowers provide nectar for bees, butterflies, hummingbirds, and other beneficial insects throughout the summer bloom period. [source]
Traditional herbal uses
MedicinalHistorically used by Native Americans for various medicinal purposes including skin conditions and digestive issues, though modern herbal use requires professional guidance. [source]
Cut flower arrangements
HouseholdThe large, fragrant flower clusters make excellent long-lasting cut flowers for arrangements, and the seed pods add interesting texture to dried arrangements. [source]
Seed pod crafts
CraftThe distinctive bumpy seed pods and silky seeds are popular for dried flower arrangements, wreaths, and educational displays about seed dispersal. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Allow seed pods to mature and dry on the plant; harvest in late summer or early fall when pods begin to split. Collect pods just before they burst open and place in a paper bag to dry completely. Seeds can be stored in cool, dry conditions for several years. Do not harvest during active monarch caterpillar season (mid-summer through early fall) if monarch conservation is a priority.
Fun Facts
- 🌱 Monarch butterfly caterpillars are among the few insects that can safely eat milkweed despite its toxic cardiac glycosides; they sequester these toxins for their own defense against predators.
- 🌱 Showy milkweed is native to western North America and thrives in the dry climates where traditional milkweed species struggle, making it perfect for water-wise gardens in those regions.
- 🌱 The name 'milkweed' comes from the milky latex sap that oozes from broken stems, which was historically used for various purposes including waterproofing and medicinal applications.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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