Field Guide     Weed Management     Milkweed

Milkweed (Asclepias L.)

Crop Impacts: Livestock and field crops that do not produce a lot of shade

Milkweed 1

About Milkweed:

Milkweed is a perennial plant that can be found in Canada and the northern parts of the United States. However, it is very commonly found in the central- east part of southern Ontario, along with the Manitoulin Islands. The reproduction of this weed occurs through seed and the spread of their root, creating new shoots of plants. The unique feature about this weed is that the entire plant produces a thick, milky white sap that is poisonous.

Family: Dogbane/ Apocynaceae family

Milkweed 2 Milkweed 3 Milkweed 4

Milkweed Scouting and Prevention:

Milkweed has many stems that grow in a cluster close together with rounded leaves and a slight point at the top. This plant also has flowers that bloom in the middle of June until August with a greenish, purplish, or whitish colour to them. They also produce a fruit that starts green and eventually turns brown. It is oval shaped with a pointed end and bumps all over its body. At full maturity in August to October, the fruit will split lengthwise releasing flat, oval seeds with long and silk hairs attached to each. When looking for Milkweed, the best place to find it is in pastures, meadows, wastelands, roadsides, and on cultivated land.

Milkweed Control:

The best way to deal with Milkweed is to mow it down before the plant has reached full

maturity. Cultivation is another way to destroy the seeds of the Milkweed; however, it

will not get rid of the plant forever due to the fact that the roots are so deeply embedded into

the soil. Putting crops into your fields with high shade canopy will subdue the weed.

If this does not work, you can systematically apply herbicide during the

spring while the plant is 12 to 18 inches tall, or in early to midsummer when the

plant is still budding.

Latin / Alternative Milkweed Names:

  • - Asclepia syriaca

Additional Milkweed Resources

http://www.omafra.gov.on.ca/IPM/english/apples/weeds/common-milkweed.html

http://ontariowildflowers.com/main/species.php?id=84

http://extension.psu.edu/pests/weeds/weed-id/common-milkweed