Written by Naomi Sager

In our commons garden bed right now, there’s a particular pink plant in bloom which has been attracting a large quantity of pollinators… it’s swamp Milkweed!

Swamp Milkweed is one of 14 varieties of milkweed native to Canada. Swamp milkweed is considered a native species in Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia, and PEI. Swamp Milkweed is a perennial and, as its name may suggest, it is particularly suited to growing in swamp-like conditions: it thrives in moist environments, and is very tolerant to clay-heavy or acidic soil conditions. Unlike Common Milkweed, which spreads prolifically, Swamp Milkweed tends to be less invasive and prone to spreading, therefore making it a more ideal choice for placement in gardens. 

Swamp Milkweed grows between three to six feet tall, and produces clusters of small, pink flowers in the summertime. In the fall, the blooms turn into relatively large (about 5inches long) seed pods, which contain a number of individual seeds, all of which are attached to a silky “fluff” that allows them to easily travel in the wind.

Milkweed sap is latex based and contains toxic compounds, therefore detracting a variety of insects and herbivorous animals from consuming it (making it an ideal choice if you’re looking for a deer-resistant plant!). Interestingly, these noxious compounds work to the benefit of monarch butterfly caterpillars, who feed exclusively on the leaves of milkweed. The consumption of the toxins in the sap serve to make them unpalatable to most predators.

While the understanding of the importance of Milkweed as a food source for monarchs has garnered significant attention in recent years, there is another fascinating aspect to Milkweed which has received much less attention: the silky “fluff” attached to the individual seeds possesses an impressive potential. The fluff has been found to be six times more buoyant than cork, and an incredible five times as warm as wool!

In fact, there is a Canadian company currently producing outerwear which uses this down alternative (https://www.ctvnews.ca/mobile/sci-tech/how-milkweed-stuffed-winter-coats-could-help-monarch-butterflies-1.4062066), and in Quebec, there are an increasing number of farms producing milkweed crops to accommodate this innovative use. Another innovative use of the milkweed fluff that is being researched is its potential as an absorbing product for oil spills, as it has been demonstrated to absorb oil, but not water.

Evidently, in addition to keeping monarch caterpillars fed, milkweed has a plethora of innovative uses. Indeed, its true potential is only just beginning to be discovered!