{Almost} Wordless Wednesday :: Common Milkweed (Asclepias)

Posted on: October 1st, 2014 by Trillium Art


Today’s discussion about the Common Milkweed could continue as a small book or at the very least a very long blog post! There is much to say about this native perennial including the dependence of Monarch Butterflies. In order to keep todays post on the shorter side, let’s explore some of the highlights of this wildflower.

Milkweed is an important nectar source for bees and other nectar seeking insects, butterflies, even hummingbirds! This wildflower is often found in pastures, fields, open woods, roadsides and along railroad tracks.

The milkweed is named for its white sap that is excreted when the plant is broken. It is considered toxic and is included on the noxious weed list in Ontario, Quebec and Manitoba due to some evidence suggesting that the species is thought to be poisonous to livestock. The plant contains cardiac glycosides, which are toxic to animals; sheep are mostly at risk but other livestock could be affected if large quantities are eaten. Most recently, documents suggest the milkweed might be removed from the noxious weed list as it plays an important role in the native biodiversity in Ontario. Farmers now have a number of management options available to reduce the threat that milkweed poses to their livestock on lands that are being farmed.


Milkweed plants are essential to Monarch butterflies. This is the only plant on which the eggs are laid and the only food source for the caterpillars. The toxins mentioned above work in the butterfly’s favour as the poisons are absorbed into the caterpillars making them distasteful to most predators. The declining numbers of Monarchs over the last decade has been partially blamed on the loss of the milkweed plants and corresponding habitats. However, there is good news on the horizon! According to Monarch Watch, the migration of the Monarch is underway and reports indicate that the population in their overwintering location in Mexico is expected to be larger than last year!

Many people are wanting to help the Monarchs, other butterflies and insects that are struggling against the changes in their habitat. Should we be planting milkweed in the gardens? Keep in mind that milkweed is not only toxic to humans but quite invasive as well. It spreads by seeds on the wind as the pods or follicles burst open this time of year but also by the rhizomes underground. If you have the space, the butterflies will love you! Several suppliers have recognized the need for these plants and have included them in recent development programs. Be on the lookout for different varieties such as Soul Mate Milkweed (a clump-forming plant that will not spread).


Zone: 3

Light Conditions: full sun

Height: 48” when mature

Foliage: large, broad leaves (Monarch butterfly eggs are laid on the underside of young, healthy leaves)

Flower Power: sweet-smelling, pinkish-purple clusters from June to August

Seeds: the seeds have white, silky, filament-like hairs and when the seed pods ripen and split open, the seeds are blown by the wind

Tip: can spread by seeds on the wind or by rhizomes underground, deer resistant, can be considered a vigorous and weedy wildflower

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