Laura passes out maps to the cut-back crew indicating which areas should be mowed completely.
In early 2018, Laura Ekasetya, the garden’s former Director and Head Horticulturalist, embarked on a new experiment to be more helpful to native bees and other bugs, especially in light of insect populations plummeting, by not cutting parts of the garden all the way to the ground.
In 2018 designated areas for reduced cutting were flagged to give the crew a visual guideline as to where to stop mowing.
During the growing season, many insects use standing spent plant stems as nesting sites, particularly the bottom 15-inches of the stem. According to insect expert, Heather Holm, “Cavity nesting insects which include most cavity-nesting bees and some solitary wasps use the hollow stems…A few bee species, including small carpenter bees and mason bees, construct their nests in pith-filled plant stems, chewing the pithy material from the center of the stem to create a nesting cavity.”
“A small carpenter bee enters a nest in a plant stem.” – Image and caption by Heather Holm.
An array of tulips wouldn’t be as instagrammable mixed in with a bunch of twigs sticking up from the ground, so it was decided to experiment slowly while leveraging the strengths of each area of the garden. Laura surveyed the overall design plan and chose areas that are a little less picturesque in the very early spring to leave 15-inch stems standing and areas where tulips and crocus bloom en masse were cut down completely as previously done. By mid-spring, the standing stalks were camouflaged by the grown plants and looked as it always has.
Areas that are mowed down completely are areas where a clean pallet is essential for the garden’s design features.
Even though most of the garden continues to be cut back completely, it still offers plenty of ecological value. As the mowers pass, the plant material is coarsely chopped to stem pieces that are 3-12″ long and left on the ground which acts as a natural mulch. This mulch keeps moisture in the soil, provides nesting materials for birds and insects, and fertilizes as it decomposes.
As the mulching mowers pass, the plant material is coarsely chopped and left on the ground which acts as a natural mulch. While some overwintering insect’s habitat could be damaged in this process it is the least damage we can manage and still balance efficiency and aesthetics.
For 2019 the mowing plan included an expansion of the areas reserved for insect habitat. As the season proceeds, the staff will assess how the respective areas fill out, to see how the mowing/insect nesting areas for the next winter could be adjusted to add the greatest value.
The areas reserved for insect nesting habitat more than doubled between 2018 and 2019. The areas will be assessed during the year and be adjusted if needed for the following year.
We may end up not knowing how many insects take advantage of the stems left up for them, and that is ok. As visitors, maybe some who may care for other gardens, come through the garden they may notice this unusual ‘gardening’ technique, learn about its benefits, and cause them to not cut back their gardens as severely as they used to.
According to Heather Holm insects like plants with “long, linear, strong flower stalks.” In her book, Bees: An Identification and Native Plant Forage Guide she lists asters, goldenrods, thistles, bergamot, black-eyed Susans, and coneflowers as some plants they may favor for their nesting.
Signs are posted around the garden to inform visitors as to why stems were left standing, hopefully inspiring other gardeners to refrain from cutting back their gardens completely too.
Meanwhile, the Lurie Garden staff will be on the lookout for nesting insects this growing season. They will look for pith particles coming out of the tops of some of those stems or small fresh shavings on the ground around stems as evidence that keeping this nesting area is really paying off!
This is what success looks like! As insects burrow into a stem, pith can be left at the entryway to their new nest! These insects will emerge from these stems the following spring. Photo by Heather Holm.
Here is a great visual guide for this process.
Let us know if you find any nesting insects and what you think about our experiment, especially as the spring progresses!
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Thanks for the info. Yesterday I cut back my garden by hand using Lurie as an inspiration. I will look for nesting insects.
I have more to cut back and will keep some to the 15” you mentioned.
Hi Howard! That’s so great to hear! Let us know if you find any!
This is awesome – I’m going to share with our garden club so that folks can take note and do this in their home gardens. Thanks for setting the example.
Hi Cathy,
Thank you for sharing! We hope the word spreads – the insects really need us right now!
This practice is incredibly important. Thank you, Lurie, for being environmentally aware. These gardens need to be for wildlife, too. Insects are struggling, worldwide, and urban/suburban gardens are some of the last safe habitats for pollinators.
Thank you, Leslie! We always feel lucky when we see wildlife using the garden as a place to live and rest!
read article about cutting back certain areas – keeping other areas trimmed for insect over wintering. I intend to try same method in my yard
Hi Fred!
This is great news! In the spring it can look a little stick-y but by mid-May, they are covered with new spring foliage. 🙂
Let us know how it goes!
Recently purchased a small mason bee house from Costco. Do you have a suggestion for where it should be located in our garden to ensure success?
Hi BJ,
Oh cool! We’re not bee experts but various sources seem to concur on the following points:
-Mounted against flat surface and level to the ground if not pointed slightly downward for rain drainage.
-The front of the bee house should have early morning sun exposure (east or maybe southeast).
-At least 3 feet from the ground.
We’d think if these above points are followed the bees know what to do and can get to where they need to go after that. Let us know if you end up finding/learning new tips or find a good resource for this information!
It’s nice to hear Costco’s serving their bee-loving customers 😉
Good luck!
This is fantastic, thank you! Do you have a short list of plants we should start leaving up? Wondering if there are some known or obvious plants to start with.
Hi Meredith!
According to Heather Holm they like plants with “long, linear, strong flower stalks.” In her book, ‘Bees: An Identification and Native Plant Forage Guide’ she lists asters, goldenrods, thistles, bergamot, and coneflowers as some good plants for their nesting. We thought one interesting thing she mentions is that mint-family stems are less desirable because they are segmented. Her books are really great and her Instagram is addictive. (@beesnativeplants).
This is a good question, I’ll add this info to the post above. Thank you!
Interesting! I maintain a green roof garden for a client in Edgewater on the 18th floor. I will leave the bergamot and rudbeckia stems up and cut down all the others and see if I see any pilth this year! It will be interesting to see if they nest on the 18th floor!!
Hi Linda,
That’s really great to hear – let us know if you find any
Fingers crossed!
Beautiful garden, thoughtful and thorough representation by Jo Ana Kubiak. I highly recommend a tour and visit. Come plan to spend time enjoying the peace and scenery. Loved it. Thank you Jo ana.
Thank you Karmina for your kind words and recommending us.
I’m really glad you enjoyed your visit!
At our church’s Pollinator Garden we’ve been leaving all stalks up over winter for the past four years, since it’s start. After our last frost date we cut back to 12-15 inches. Xerces and Audubon recommend this approach.
That’s so great! Have you gotten lucky enough to see any nesting insects?
Sorry I missed this post until now. I’d say this is definitely a worthwhile effort. I think it will take some experimentation to find the right balance between leaving stalks alone and making the garden look neat and “clean” for the new season. Unfortunately, I haven’t had a chance to see the Lurie Garden at all this year, so I can’t comment on the new approach to cutting back. This year I hired a landscaper to do my spring cleanup and definitely regretted the decision. Though they promised to do otherwise, they just blew every bit of organic matter out of the beds and hauled it away.
Hi Jason, During her visit, we invited Jacqueline van der Kloet to weigh in on the cutback lines to make sure they mesh with her incoming design update. We’re keeping an eye on the new areas we experimented with not cutting back this year and there may need to be some adjustments. It’s probably hard for landscapers to trust a client means what they say when they ask for a spring cleanup that leaves things ‘messy.’
Great Info, I applied this in cutting my garden after winter. The nesting insects area is awesome. But how can we make it beautiful as it looks quite boring? Plz, share some tips for making it adorable.
I am also using the mulching technique in my garden. It works really well.
For less cultivated soil, it acts like fertilizer. Hopefully, you will write more about gardening tips. I would really appreciate hearing from you!
Hi James,
It can be tricky to make it “look good” too. We try to keep sight-lines in mind, we double-check how it looks in the spring, adjust the lines and apply the new lines the next winter, repeat. Jacqueline van der Kloet, who designed our Spring Display made sure she designated many bulbs that will grow to be taller than the ‘sticks’. That was helpful. The sticks look fine, even interesting when everything is just sprouting. Then there is a weird ‘teenage’ phase where everything is sort of the same height and it’s a little awkward, but quickly after that, you never notice them if you’ve put plants with plenty of foliage about the height of the sticks.
But I think a change in how we look at it may help us join the ranks of people who really love the sticks – I believe they’ve altered their view that nature isn’t here solely to bend to our enjoyment and our idea of beauty. Maybe they see it like “here are the flowers and over there are the bee houses?”
Thanks for helping to get this important message out! I agree it is so important to leave pithy stems- as many as possible- for the bees. At my house I find loads of stem that have been burrowed into- especially hydrangea, grapes, raspberries. I also leave the leaves on the ground in my beds as-is with the knowledge my perennials come along shortly to cover them. Perennials and shrubs with nice, straight stems that must get cut back get bundled and tied to a fence or laid in a neat pile in a quiet corner of the yard.