Habitats of Overwintering Insects

Okay, I agree this isn’t a very sexy photo to start off with but it does tell a story. We’ve had some crazy temperature swings this spring here in the upper Midwest, (including two inches of snow yesterday) and I have been putting off cutting down any plant material in my landscape.

As gardeners we are told to “clean up” our gardens in the fall, cut down plant stems (except ones that provide winter interest) and rake/blow every last leaf out of our yards. What we are in fact doing is removing the overwintering habitat of insects that the wildlife (birds, amphibians, reptiles, spiders) will need next spring to feed upon and rear their young.

So back to the first photo, there’s leaf litter, rocks, grass blades and plant stems. The only thing missing is some nice logs on the ground with a bit of loose bark to curl up underneath.

Consider the Life Cycles of Insects
Insects can overwinter in several life stages including adult form, egg, nymph, larval and anything in between. Many insects undergo a period of suspended development called diapause, similar to hibernation. They seek out protection under leaf litter, tree bark, rocks, clumps of grass or plants, logs on the ground, and in hollow plant stems. (BugGuide.net) Some of earliest emerging butterflies like the Mourning Cloak and Eastern Comma overwinter in adult form and need somewhere to weather the cold winter temperatures.

In the second photo (late April/early May), the plant material on our front hillside has been cut down and almost all of it left in place as a mulch around the plants. I do take away the large stiff stems of Cup Plant (Silphium perfoliatum) for example, because they’re hollow and make excellent solitary bee nests. Just cut to lengths of 12 inches, bundle togther and hang in a sunny location.

Depending on the species of insect, the life cycle development can vary greatly but you can make a huge difference by leaving the plant material up for the winter and not removing the leaf litter. I attended a talk this winter by University of Minnesota Entomologist Vera Krischik, who said that in the spring it is important to wait until temperatures reach at least 50 degrees F to ensure that overwintering insects have emerged.

In the third photo, (mid August) no plant debris from the previous year is visible as it gets covered with the growing perennials.

What’s So Great About Encouraging Insects in My Yard?
Insects are the phytoplankton of the non-aquatic world. They are the foundation of the entire foodweb for wildlife. Native plants play an equally important role in this foundation, providing the habitat, nectar and food for insects.

We have incorporated logs into our naturalized woodland specifically for insects. They provide excellent habitat and woodpeckers will come and peck away at the logs seeking out the insects. Logs on the ground also help retain soil moisture – native shrubs and perennials that were planted near logs have grown almost twice as large as others not planted near a log.

Not sure if you like the ‘look’ of a log in your garden? Plant native shrubs and perennials around it so it will be become covered in the summer months.

Adding or leaving leaf litter, logs, plant debris and rocks in your garden will provide excellent insect habitat and ultimately attract more wildlife. You can’t build a house without a foundation and you can’t garden for wildlife without fostering the entire life cycles of insects.

© 2011, Heather Holm. All rights reserved. This article is the property of Native Plants and Wildlife Gardens. If you are reading this at another site, please report that to us

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    About Heather Holm

    Heather Holm is an horticulturalist, photographer & graphic designer who is passionate about native plants, landscape restoration and observing, attracting and documenting wildlife in her yard. Her 2/3 acre landscape in suburban Minneapolis is a Certified Monarch Waystation and received a first place award from the watershed district for the "Best Landscape Restoration" in 2009. She is an active member and volunteer of Wild Ones (Twin Cities Chapter) promoting the preservation and use of native plants in the home landscape. She also volunteers her time with her municipality in landscape restoration projects and writing grant proposals for restorations. She is also author of the popular blog, Restoring the Landscape With Native Plants and the corresponding facebook page.


    1. Benjamin Vogt says:

      Shoot, not cutting down in fall makes winter better for me–it’s like I still have a garden out there if I leave it all up. Plus, I’m tired in October and November.
      Benjamin Vogt recently posted..The Naming

    2. Heather Holm says:

      Hi Benjamin,
      I couldn’t agree more, I like to wind down in the fall and just enjoy the landscape. It also seems like less work in the spring with renewed energy.
      Heather Holm recently posted..Native Plant of the Week- Sharp Lobed Hepatica Hepatica acutiloba

    3. Donna says:

      Heather I will admit that for me I have to cut down stuff in my garden in fall because spring is too busy in my day job and the vole damage is worse sometimes although I may be changing that opinion…but I leave so much and I leave the debris …also in the spring I don’t clean it up as pretty as I used to…I leave lots because the insects love it and so do the plants…
      Donna recently posted..Earth Day

    4. Heather Holm says:

      Hi Donna,
      It sounds like you’re leaving plenty of debris and leaf litter to help insect populations! I have a lot of voles too but have not experienced too much damage. I do put plastic guards on many of my woody plants for the winter, especially since we get so much snow.
      Heather Holm recently posted..Native Plants &amp Wildlife Gardens

    5. Candy DeBerry, Ph.D. says:

      I leave all my dead plant material standing over the winter. I do spend about two days in late March (during our Spring Break week) cleaning up the front yard. The (larger) backyard gardens get tidied up as time permits in April, May, and June. And that means that the standing material is cut into smaller pieces and left as mulch in the beds. I used to put it through my electric chipper/shredder, but the last two seasons I’ve just chopped it into pieces and dropped it on the ground. The difference that this has made in the insect diversity on our 1/3 acre lot is astounding. In summer, our yard swarms with lightning bugs while the similar-sized grass lawns of our east and west neighbors are almost devoid of lightning bugs.

    6. Heather Holm says:

      Hi Candy,
      Thanks for sharing about how you’ve increased insect diversity. How wonderful to have lightning bugs!
      Heather Holm recently posted..Native Plants &amp Wildlife Gardens

    7. Carole Sevilla Brown says:

      Heather, it’s so important to consider the entire life cycle of the insects and other wildlife when we are trying to create welcoming habitat for wildlife in our gardens. This is a great lesson you’ve shared. Thanks :)
      Carole Sevilla Brown recently posted..Early Spring Blooms in My Wildlife Garden

    8. Heather says:

      Thanks Carole,
      I saw yet another example of this last week, the tiny carpenter bees pollinating my bloodroot overwinter in chewed out plant stems.

      • Carole Sevilla Brown says:

        That’s so cool, Heather! It’s for that reason that I never cut back my plants until springtime. I’ve read that many insects overwinter in them, and now you’ve seen it. Awesome!



    1. We Have a Sister says:

      [...] Heather Holm, of Restoring the Landscape with Native Plants, talked about Habitats of Overwintering Insects [...]


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