Milkweed is not a garden plant


by W.J. Langenberg,
ret. Env. Biol.; Hort. Ext. OMAFRA, Kemptville College

Milkweed, also called Side Plant, because of its sideways later growth, has a latex milky sap, which is toxic to farm animals if consumed in large quantities. Goats, sheep and rabbits can be poisoned. It is very invasive. The roots grow horizontally up to 6-10 feet. Along the creeping horizontal roots, buds are produced that will grow into new plants. One plant can produce a colony of milkweeds.

It self-fertilizes (no pollinator needed). Pollen is not produced, but microspores, which change through meiosis into fertile pollen grains. The microspores are carried over a large area in the wind. The seeds produced after fertilization are also carried by water and by air to other locations.

Milkweed should only be found NATURALLY on non-arable farmland surrounded by windbreaks. Perhaps, in consultation with NG Council, Milkweed can be grown on top of the hill behind the Maple Orchard, planted in 1978 (Concession Road, across from the schools). It is surrounded by trees, which will restrict the movement of the Milkweed seeds to other areas.

If Milkweed is planted on abandoned farmland, make sure that the field is protected by windbreaks, such as spruce/pine trees on the north and west side of the field. Windbreaks will stop the aerial transport of Milkweed seeds and microspores. Do not contaminate nearby farm fields used for field crops, including hay. Horses hate to eat hay contaminated with Milkweed.

Milkweed is a NOXIOUS WEED. If there is too much of it on farmland, more chemical spraying is needed to control it. Let’s protect Agricultural and Horticultural crops for food production.


  1. Of course colonial farming practices advocating for the extinction of several native flora and fauna. Only to replace them with flora and fauna that don’t belong on this continent.

  2. Of course colonial farming practices advocating for the extinction of several native flora and fauna. Only to replace them with flora and fauna that don’t belong on this continent.

  3. This article is offensive and ignorant. Quite disappointed in both the author and the publisher. Beneficial, native, pollinator-supporting plants do not meet the definition of “invasive.”

  4. This article is full of misinformation. Milkweed is native to North America and that means it cannot be invasive. It may be aggressive and an annoyance in agriculture, but it supports many important species of pollinators. If they die so do we.

  5. Common Milkweed is native to Ontario, therefore NOT invasive. Invasive plant examples would be garlic mustard or Japanese knotweed, neither of which have any use to our native fauna and outcompete native flora leading to the reduction of biodiversity. As an environmental biologist you should know this is what *actual* invasive plants do.
    Milkweed is the ONLY host plant for the monarch butterfly, whose numbers are dwindling thanks to the OUTDATED misinformation in this article. It is also pollinated by and acts as a nectar source for DOZENS of species of flies, moths and butterflies. I’m not sure who approved this article for publication but they need to give their head a SHAKE! The grammar is also atrocious, learn how to write in proper sentence structure and create flow in a piece of writing!

  6. Farm animals eat around these plants, and they are a natural part of the environment. This article doesn’t belong in this century, the author and the editor of this paper should do better!

  7. Farmers who maintain their pasture by cutting on a monthly basis won’t have problems with milkweed. As stated in other comments, this is a very misleading article that is using out dated misinformation.

  8. Milkweed is not invasive. Milkweed is not self- fertile. Milkweed does need to be pollinated by insects. Milkweed does not occupy the noxious weed list. It’s a crucial part of Ontario’s natural flora, and reading this article was embarrassing. The thinly-veiled agenda is upsetting. Please consult with an expert in this field next time (which you clearly aren’t) before posting misinformation that threatens to extinct a struggling species.

  9. The publisher should have researched the information in this article, it has been several years that milkweed has been removed from the noxious plants list. Milkweed is necessary to help bring back the monarch butterfly.

  10. Words cannot adequately convey my gratitude for the valuable insights I’ve gained from this website. Your commitment to educating and empowering others is truly admirable, and I’m grateful for the impact it has had on me. This platform has become an indispensable resource for me. Thank you for providing such a valuable resource for continuous learning. Thanks Mate! ID : CMT-SPEFX32M977KIXR1OM


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