March - Designing with Trees | April - New plants, now what? | May - Lawn weeds

herbicide damage
herbicide damage

My Yard - May

The Dandelion Blues

Thank goodness spring has arrived. It causes so much hope that even Cubs fans start dreaming of a World Series championship. Wait, that really happened! It’s also the time of year when many plants put forth flowers as they try to reproduce themselves. Most springs, we humans get a front row seat to some of nature’s finest pageantry expressed through a kaleidoscope of flowery display.
        When it comes to flowers, beauty is in the eye of the beholder, and the lowly dandelion is one of the least appreciated. Most adults who care for lawns go to great lengths to eradicate it. What causes us to have such deep disdain for the dandelion? It’s a plant with a pretty yellow flower that is easy to grow, reliably green, helps cover the ground and can even be harvested and eaten. Why is it so despised, while the boring stretches of bluegrass where it grows are so celebrated?
        Dandelions aren’t the only flower we loathe in the spring. Violets, henbit, clover, mallow, pennycress and ground ivy also get our goat. What they have in common is that they’re all “lawn weeds,” prone to blemishing the perfect carpets of grass we’ve worked hard to achieve. Wanting to rid ourselves of these weeds is understandable since they upset our sense of order and control.  
        Unfortunately, our efforts to eradicate these weeds is not a benign exercise. Many trees, shrubs and other landscape plants we love are regularly damaged by unintended drift from broadleaf herbicides sprayed on lawns. It’s a growing problem and the damage becomes more acute every year. Although part of the problem comes from agricultural spraying, our efforts to control lawn weeds account for a significant portion of the damage, particularly in urban areas.
        One of the main problems is that spraying for dandelions typically occurs when many of our trees and shrubs are just starting to leaf out, and their tender young foliage is especially susceptible to herbicides. The worst damage seems to occur on oaks and redbuds, but many other species, including ginkgo, viburnums and dogwoods, are also susceptible.        It doesn’t need to be this way. One solution is to simply ignore spring lawn weeds. In the grand scheme of things, are they causing any important economic or ecological harm? Almost always it’s primarily a cosmetic issue. Many “weedy” species are actually quite beneficial. Almost every weed we’ve mentioned, including the lowly dandelion, is now recognized as an important nectaring plant for early season pollinators, especially several varieties of bees. And those vagabond violets are critical to sustaining fritillary butterflies, which are in decline.
        For those who still want a weed-free lawn, the best time of year to spray herbicides is in the fall. That is the time of year when perennial weeds are pushing energy and nutrients to their roots and thus are more effectively killed. It’s also the time of year when most trees and shrubs are going dormant and are much less susceptible to herbicide damage. That sure sounds like a win-win—better weed control and less harm to non-target plants.
        So why is the dandelion so despised? The biggest reason might be because it is so common. Andrew Mason summed it up well when he said, “if dandelions were hard to grow, they would be most welcome on any lawn.”

My Yard for May, written by Justin Evertson