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There is something about mowing that brings a measure of satisfaction to many of us. What is it that we love about mowing? The smell of cut grass? Taming an unruly landscape? To me, it is measurable progress. It seems so often that modern jobs give few tangible results. So much of our work these days is in the digital ether. After a full day's work, I leave the office switching off my computer, and all my toiling vanishes with the click of a mouse.

Arriving at home, I seek tasks of visual permanence by working with my hands, cleaning, and of course mowing. This desire to mow often expands beyond the yard as many landowners also mow road banks and ditches.

Unfortunately, the constant routine of mowing is harming the monarch butterfly, due to the loss of milkweed. August and September are critical months for the monarch butterfly. This timeframe is when the final generation of the year develops and prepares to make their flight to their overwintering site in Mexico.

I don't want to burst your mowing bubble, we can all still hop on the zero turn and get our fix, but there are times when we should avoid mowing areas like ditches, road banks, natural areas, or anywhere that harbors milkweed, the only plant that monarch caterpillars eat.

For those living south of the 40-degree latitude line (includes Quincy and on into southern Illinois), mow before April 1 and mow after October 15. If necessary, you can also do a mid-summer mowing July 1 to July 20.

For those living north of the 40-degree latitude line (includes those north of Quincy and up into northern Illinois), mow before May 1 and mow after October 1. A mid-summer mowing can take place June 30 to July 10.

These dates are based on monarch breeding and migration activities. The mid-summer mowing will still cause some mortality of monarchs.

Other tips for mowing habitat or roadsides:

  • Don't mow the entire area. Leave unmown strips to recolonize the cut areas.
  • Avoid mowing at night when insects are inactive and cannot escape.
  • Use a minimum cutting height of 8-12 inches. This height removes seed production for many invasive plants while minimizing impact to native plants.
  • Use a flushing bar and mow slowly to allow wildlife to escape before the mower passes over.

Milkweed is a disturbance species, and mowing can promote its growth but can be damaging if done during peak times of monarch reproduction and migration. Follow the above-stated mowing guidelines, can help preserve vital monarch habitat. Check out Monarch Joint Venture's brochure Mowing: Best practices for monarchs.

If you want to learn more about monarch butterflies, join us for our annual Monarch Migration Festival on September 8, 2018, at the Lakeside Nature Center in Galesburg, Illinois. It is a fun-filled day starting at 10 AM with activities for the whole family.

  • You will see real live monarch butterflies and caterpillars
  • Explore the Ms. Mari Posa mobile classroom
  • Send your own symbolic butterfly to Mexico
  • Purchase native plants
  • Learn about beekeeping
  • Talk to local conservation experts
  • Build monarch rearing cages
  • Dress up like a butterfly for the monarch parade at 2:30
  • Fill out an event passport to win a chance to release a butterfly
  • Enjoy vendors, music, food, crafts, talks, and of course butterflies!

The festival ends at 3 PM with a release of Monarch butterflies. For more information on monarch butterflies contact the Knox County Extension office at 309-342-5108 or visit our website at

The University of Illinois Extension will also be a guest booth at the Macomb Farmers' Market on September 22. Master Gardeners and Master Naturalists will teach youth through hands-on activities how they can help monarch butterflies.