I know what you’re thinking: “No Mow May? But it’s March!” Although spring currently seems like a distant wonder for us here in Montana, many of our warmer states are seeing the signs of spring that get you thinking about, among other things, your lawns (and if you’re a bee enthusiast like myself, you’re also thinking about the early season pollinators that are beginning to emerge in these landscapes).
What is ‘No Mow May’?
No Mow May (or April, or March- depending on where you are) is a movement that was originally made popular through an organization based out of the United Kingdom called Plantlife. The intention behind the campaign is to eliminate mowing your lawn for the month of May, with the goal of creating habitat and floral resources for early-season pollinators. This initiative has since become more and more popular in the United States in addition to other countries, where we see the classic image of a turf lawn speckled with bright yellow dandelions along with signage that says ‘No Mow May’.
Lawns are a staple of American landscaping and one can hardly imagine urban and suburban areas without the iconic image of the green turfgrass yard associated with many homes. We have about 40 million acres of lawn, which accounts for 2% of all the land in the continental US, making lawns the number 1 irrigated crop in the country! The ideal vision of a good lawn has long been a weed-free, monocultural, uniform green space and people spend a lot of time, effort, and money to maintain them in this way. The image of overgrown, non-uniform, unconventional, and weedy lawns have been historically considered to be unattractive, unkempt, and poorly managed. Although more and more people seem to be changing their opinions and preferences for these conventional turfgrass lawns (and we likely need to rethink some of these expectations anyways), most people still have those underlying perceptions.
The idea behind No Mow May is that flowering lawn weeds, if left unmown, would provide food sources for early season pollinators such as newly emerging native bees (with the added benefit of less work in terms of lawn maintenance). The primary targets of this initiative are generally more urban and suburban areas where food sources and habitat for pollinators can be harder to find and spaces where weedy lawns are less tolerated.
Although the intention behind this campaign is a good one, providing food for pollinators, there are some aspects of this initiative that seem to miss the mark.
So let’s get into some of the science!
Is ‘No Mow May’ good for pollinators?
The answer to this question is: yes and no.
Studies have shown that certain common flowering lawn ‘weeds’ can be an important food source for pollinators, especially in urban and suburban areas where other floral resources can be scarce. A paper from the University of Kentucky found 50 species of pollinators, including 37 species of bees, foraging on white clover and dandelion in lawns (Larson et al., 2014). Although white clover is a nutritious source of nectar and pollen for bees, dandelions on the other hand are not very nutritious (with low protein content in their pollen). That being said, bees and other pollinators will still forage on dandelions especially if other floral resources are unavailable at that time. In the ideal world we would have a plethora of floral resources for pollinators which would incorporate an abundance of diverse flowering plants from early spring all the way through the growing season and into the fall. Unfortunately, most urban and suburban spaces do not meet the specifications of this ideal pollinator-friendly world. Dandelions, on the other hand, are pretty universal in these urban areas (and you have likely seen them in many lawns in your neighborhood). Although they are not a great resource, abundant dandelions can fill the gaps of food sources for bees (especially when the alternative is no food). Other lawn ‘weeds’ and bee lawn plants (as you have seen in last year’s blog post) can also support a diversity of pollinator species and can be a great way to offset the lack of pollinator-friendly resources in a turf-only lawn.
Research from a pilot project of No Mow May in Appleton Wisconsin evaluated the bee species richness and abundance in properties that participated in the initiative and found a higher species richness and abundance when compared with areas that had been mowed, but this paper was retracted shortly thereafter, so it is difficult to judge the validity of those results.
That being said, if left unmown: your turfgrass will soon outgrow any other flowering lawn weeds which can make them difficult to find for pollinators, and that is if these flowering lawn weeds aren’t smothered by the tall grass altogether. A study conducted in Massachusetts which evaluated the impact of mowing frequency on bee abundance and diversity showed that lawns which were mowed once every 3 weeks had 2.5 times more flowering plants, though lawns which were mowed every 2 weeks had the highest bee abundance, likely due to easier access and visibility of these floral resources in shorter grass (Lerman et al., 2018).
Is ‘No Mow May’ less work?
The answer to this question, as you probably could guess, is also: yes and no (but mostly no).
I am a self-proclaimed ‘lazy gardener’ and am always looking for ways to reduce the amount of effort I need to put into my gardening endeavors. No Mow May claims to be less work for you in the month of May. Although that is true (because the intention is not to mow for a month), it can often result in more long-term effort in trying to reign in your turfgrass in the after-effects. Not to mention the negative impact that this style of management (or lack thereof) can have on your turf itself.
In many places, lawns can grow a foot or more during the month of May. An un-mown lawn can set you back on your lawn maintenance and result in more work for you in the long run . Then when you are trying to get your lawn back on track afterwards- remembering the rule that you should only remove 1/3 of your turf in any given mowing, it could take weeks to get back to a good functional height (which varies depending on the type of grass, but for most of our lawns, it ranges between 2.5-4 inches). Furthermore, most mowers don’t have the capacity to handle a lawn with a 12 inch height. This will result in removing too much of the grass leading to unintended consequences like stress and decline of your lawn, which can also make it more susceptible to pest and disease issues. This will also lead to a large amount of grass clippings which, if left on the lawn, could smother sections of it and result in an unpleasant and patchy lawn.
Unhealthy lawns can also struggle to compete with and leave spaces open for other undesirable invasive plants, including noxious weeds. These can then spread to other areas and have significant ecosystem impacts (and make it even more difficult to get your lawn under control). Following weed management needs could also require the use of herbicides that can have unintended consequences on pollinators and other beneficial insects.
Furthermore, as noted in an article on No Mow May by Iowa State Extension’s Consumer Horticulture Specialist, Aaron Steil: lawns are not actually a natural space, as most lawns are constructed out of non-native grasses, usually for functional purposes, and require quite a bit of maintenance including water and nutrients. Leaving your lawn unmown will not make your lawn a more natural landscape, and it would not be a responsible way to manage these non-native landscape plants.
What you can do instead of No Mow May: Low Mow May!
Based on what we’ve learned so far: lawn weeds can sometimes be an important food source for bees (especially in urbanized areas, where the diversity and availability of floral resources are fewer) and mowing less frequently results in more of these flowering lawn weeds for bees. We also know that slightly higher (though not too high) mowing heights for many lawn turf species make for healthier root systems and make turf more resilient to stress, pests, and disease issues.
If you have flowering lawn weeds and pollinator conservation is your intention, your best bet would be to aim for a sweet spot between the extremes of mowing way too frequently and not mowing at all. Mowing every other week could be a way that you can reduce the amount of time spent mowing and also support urban and suburban pollinators by letting your lawn weeds flower (in addition to maintaining your lawn at the recommended heights for healthy turfgrass).
Even better yet, you can reduce the amount of space in your landscape that is dedicated to a traditional turfgrass lawn and incorporate a flowering groundcover and/or a pollinator garden that hosts an abundant array of diverse floral resources that provide food for bees all season long!
Now that’s something to be buzzing with excitement about!
University Extension, Aaron Steil: Tips for participating in No Mow May
Larson et al.
(2014): Pollinator assemblages on dandelions and white clover in urban and suburban
Lerman et al.
(2018): To mow or to mow less: Lawn mowing frequency affects bee abundance and
diversity in suburban yards
State University Extension: Lawn Care Basics