common milkweed

Asclepias syriaca

Description:

Well known a half century ago as an abundant roadside weed, common milkweed was extensively controlled by farmers and road crews across Wisconsin. The success of the weed management efforts caused a dramatic decline in the number of monarch butterflies that require milkweed plants milkweed plants as a place to lay their eggs and to nourish monarch caterpillars as they develop.

A recent scientific review recommended that the monarch butterfly be added to the federal Endangered Species list. That recommendation was rejected because there were not sufficient resources to enforce its protection under the law. Voluntary efforts are underway to increase milkweed numbers to protect and restore monarch butterfly populations.

Common milkweed is the largest and most abundant species of milkweed in Wisconsin. Other species include: butterfly milkweed, clasping milkweed, green-flowered milkweed, marsh (swamp) milkweed, poke milkweed, prairie milkweed, purple milkweed, wooly milkweed, and whorled milkweed. 

Details:

common milkweed

USDA Symbol: Common Name: Scientific Name:
ASSY common milkweed Asclepias syriaca

ITIS TSN: 30310

Category: Dicot

Taxonomy

Kingdom: Plantae

Subkingdom:

Super Division: Spermatophyta

Division: Magnoliophyta

Subdivision:

Class: Magnoliopsida

SubClass: Asteridae

Order: Gentianales

Family: Asclepiadaceae

Counties: Adams, Ashland, Barron, Bayfield, Brown, Buffalo, Burnett, Calumet, Chippewa, Clark, Columbia, Crawford, Dane, Dodge, Door, Douglas, Dunn, Eau Claire, Florence, Fond du Lac, Forest, Grant, Green, Green Lake, Iowa, Iron, Jackson, Jefferson, Juneau, Kenosha, Kewaunee, La Crosse, Lafayette, Langlade, Lincoln, Manitowoc, Marathon, Marinette, Marquette, Milwaukee, Monroe, Oconto, Oneida, Outagamie, Ozaukee, Pepin, Pierce, Polk, Portage, Price, Racine, Richland, Rock, Rusk, Sauk, Sawyer, Shawano, Sheboygan, St. Croix, Taylor, Trempealeau, Vernon, Vilas, Walworth, Washburn, Washington, Waukesha, Waupaca, Waushara, Winnebago, Wood

Natural Community: Wet-mesic Prairie

Coefficient of Conservation: 1

Duration: Growth Habit: Native Status:
Perennial Forb/herb L48(N)CAN(N)

Active Growth Period:

After Harvest Regrowth Rate:

Bloat:

Carbon to Nitrogen Ratio:

Coppice Potential:

Conspicuous Fall Color: No

Fire Resistant:

Flower Color: Purple, White, Lavender, Pink

Conspicuous Flower: Yes

Foliage Color: Dark Green

Foliage Light Porosity Summer:

Foliage Porosity Winter:

Foliage Texture:

Fruit/Seed Color:

Fruit/Seed Conspicuous: Yes

Growth Form: Rhizomatous

Growth Rate:

Height at Base Age (Max):

Height at Maturity: 6

Known Alelopath: No

Leaf Retention: No

Lifespan:

Low Growing Grass: No

Re-sproutability:

Shape and Orientation: Erect

Toxicity: Moderate

Height (min): 36

Height (max): 72

Root Type: Rhizome

Bloom Period: Commercial Availability: Fruit/Seed Abundance:
Late Spring, Early Summer Routinely Available Medium
Fruit/Seed Period Begin: Fruit/Seed Period End: Fruit/Seed Persistence:
Fall Fall No
Propogated by Bare Root: Propogated by Bulbs: Propogated by Container:
Yes No Yes
Propogated by Corms: Propogated by Cuttings: Propogated by Seed:
No Yes Yes
Propogated by Sod: Propogated by Sprigs: Propogated by Tubers:
No No No
Seeds per Pound: Seed Spread Rate: Seedling Vigor:
64000 Moderate High
Small Grain: Vegetative Spread Rate: Propagation Treatment:
No Moderate
Days to Stratify: Direct Sowing Time:
Spring, Early Summer, Fall

References:

  1. Ladybird Johnson Wildflower Center – Asclepias syriaca
  2. Monarch Watch – Milkweed Propagation
  3. Spreading Milkweed, Not Myths
  4. USDA Plants Database – Asclepias syriaca
  5. Wisflora Database – Asclepias syriaca