Toxic Plant Known to be toxic - Toxic to mammals if ingested.
Image of Asclepias syriaca
Source: Donna Bos
image of Flowering plant
Asclepias syriaca
Common Milkweed
Asclépiade commune

Obsolete Names

silkweed
silky milkweed
asclépiade de Cornut
asclépiade de Syrie
cochons de lait
cotonnier
herbe à la ouate
petits cochons
Seeds available at table Mixed Sun, Dry
We currently accept seeds for this plant
Bloom colour: Pink Bloom period: Jun - Aug
Max Height: 3.0 feet
Max Width: 3.0 feet (spreads by rhizome)
Light condition:
Full sun More than 6 hours of direct sun a day
Part shade More than 2 or 3 hours but less than 6 hours of direct sun a day
Soil conditions:
Moisture dry Tolerates dry soil condition
Moisture medium Tolerates medium soil condition
Lifespan: Perennial plants that will that come back year after year
Gardener Experience:
beginner friendly Suitable for beginner gardeners
plant self seeding Self-seeding
Landscape uses:
rock garden Suitable for rock gardens
container suitable Suitable for container garden
school garden Suitable for school gardens
boulevard garden tolerant Tolerates boulevard garden conditions
Ecological Benefits:
Pollinator garden Supports pollinators
butterfly host Butterfly host
Tolerates:
Deer Resistant Deer resistant
rabbit resistant Rabbit resistant
limestone Tolerant Tolerates limestone conditions
sand Tolerant Tolerates sandy conditions
transplantation Tolerant Tolerates transplantation
Special Features and Considerations:
septic tank safe This plant is septic tank safe

Plant Location

Native to Ottawa region: Yes

Distribution according to VASCAN

Distribution: Asclepias syriaca
Ephemeral Native Introduced Excluded Extirpated Doubtful Absent
View taxonomy on Canadensys

View on iNaturalist

Thrives in Ecozones

  • Atlantic Maritime
  • Boreal Plains
  • Prairies
  • Boreal Shield
  • Mixed Wood Plains

Ecological Benefits

Butterflies Supported by Asclepias syriaca

  • Danaus plexippus (Monarch)
  • Trichordestra legitima (Striped Garden Caterpillar)

Specialized Bees Supported by Asclepias syriaca

No bee data available for this plant.

Plants that grow in similar conditions, that bloom at the same time.

Complementary Plants

  • No complementary plants found.

Substitute For Non-Native Plants

  • Buddleia (Butterfly Bush)
  • Asclepias (Milkweed Cultivars)
  • Asclepias curassavica (Tropical Milkweed)
  • Butomus umbellatus (Flowering Rush)

Sowing Information

Download Sowing Label (PDF)
  • Sowing depth: Sow just below surface
  • Sow by March
  • Stratification duration: 30 days
  • Self-seeding

Harvesting and Seed Sharing

  • Harvest start month: August
  • Harvesting indicator: Pods are slightly open and seeds inside are dark
  • Harvesting mean: Use hand to detach from main stem
  • Seed viability test: No test needed before donating
  • Packaging measure: 1 rounded 1/8 teaspoon
  • Seed storage: Air dry in paper bag or open container, for a few days until crisp, shaking seeds to move them once in a while to prevent molding
  • At least one cultivar: No, you can donate without knowing the source as there are only straight species
  • Remove non seed material
  • Harvesting video: Watch here

Toxicity Notes

Toxic to mammals if ingested.