Common milkweed

Extremely fragrant flowers of common milkweed

Although often considered a weed, common milkweed is a nectar source for many butterflies and leaves are an important food source for the monarch butterfly eggs and caterpillars. This aggressive, native spreader reaches 3 to 5 feet high and will grow in thickets, woodland borders, fields, fence rows, and areas along railroads and roadsides.

This plant has some cultivated varieties. Go to list of cultivars.

 

Botanical name:

Asclepias syriaca

All Common Names:

Common milkweed

Family (English):

Dogbane (formerly milkweed)

Family (Botanic):

Apocynaceae (formerly Asclepiadaceae)

Tree or Plant Type:

  • Perennial

Foliage:

  • Deciduous (seasonally loses leaves)

Native Locale:

  • Chicago area,
  • Illinois,
  • North America

Landscape Uses:

  • Massing,
  • Mixed border

Size Range:

  • Large plant (more than 24 inches)

Light Exposure:

  • Full sun (6 hrs direct light daily),
  • Partial sun/shade (4-6 hrs light daily)

Hardiness Zones:

  • Zone 3,
  • Zone 4,
  • Zone 5 (Chicago),
  • Zone 6,
  • Zone 7,
  • Zone 8,
  • Zone 9

Soil Preference:

  • Moist, well-drained soil

Season of Interest:

  • Early summer,
  • Mid summer,
  • Late summer

Flower Color & Fragrance:

  • Pink,
  • Purple

Shape or Form:

  • Upright

Growth Rate:

  • Fast

More Information:

Size

Upright, 3 to 5 feet high and 2 to 3 feet wide

Tree & Plant Care

Full sun to part shade in average soil.
Often found in meadows, roadsides and along railroad right-of-way.
Spreads by runners and reseeds easily.
Common milkweed can be incorporated into mixed borders, but due to its aggressive nature, the plant may need to be thinned out on a regular basis.
Avoid pesticide use around this plant to encourage butterflies to use it.

Disease, pests and problems

Milkweed bugs and milkweed beetle are late season pests.

Native geographic location and habitat

C-Value: 0
Found in a wide range of habitats.

Attracts birds & butterflies

This plant is a caterpillar and larva host for the monarch butterfly. Creamy yellow eggs are laid on the underside of leaves.
Common milkweed  is also a nectar source for many species of butterflies. 

Leaf description

The simple, opposite arranged leaves are up to 8 inches long and 3½ inches wide,  oblong in shape, and smooth along their margins.
They are attached to a thick stout stem. The upper leaf surface is pale-medium to dark green and hairless above, while the lower leaf surface is densely covered with short wooly hairs.

Flower description

Extremely fragrant, umbels of flower clusters, about 2 1/2 to 4 inches across emerge from the axils of the upper leaves. Flowers range in color from faded pink to reddish-purple. Each flower is 1/4 inch across. Flowers bloom for several weeks in July and August.

Fruit description

The seed pods (follicles)  are 3 to 4 inches long and covered with soft prickles and short wooly hairs.  At maturity, each inflated seedpod splits  to release numerous seeds that have large tufts of white hair which help with dispersal of seed is by wind.

Related species and their differences

Prairie Milkweed (Asclepias sullivantii):  This rare native milkweed is similar to common milkweed but has larger, showier, deeper pink flowers. reaching 2 to 3 feet high and 18 to 36 inches wide, it is found in moist meadows, along rivers and near woodlands. Its flowers attract butterflies and monarch butterflies. Difficult to find in nurseries.

Location of Asclepias syriaca (Common milkweed) at the Arboretum

We do not seem to have this in our living collection.