by Carl Strang
One of my ongoing studies in recent years has been a pursuit of best practices for manual removal of garlic mustard, an invasive biennial that is one of the banes of terrestrial plant community restoration. Following an early study by researchers in downstate Illinois, I have confirmed that while uprooting of plants is effective, and is the most effective method early in the season, clipping the tops at ground level works equally well late in the season, and none of these practices increase garlic mustard seed bank germination as far as I can tell. (If you want to review my study to this point, go to the left frame of this blog and do a search on “garlic mustard.” You will scroll through all the posts in which the plant is mentioned. The first one in this study is dated March 20, 2009).
Individual hand-clipping of plants is inefficient, however, and so this year I wanted to test how well mass cutting of late-season garlic mustard plants replicates the earlier results. The problem that arose was my back strain, which made me leery of swinging the grass whip that was my chosen tool. The pressure was on, however, as this year’s early season had the plants developing apace, and so as they were showing their final flowers I decided to suck it in and give it a try. I wasn’t able to crouch down and mark out study plots as I have done in the past, and I wasn’t willing to do a lot of plots, so I settled for cutting and raking two adjacent areas dominated by dense garlic mustard plants. One of those areas I cut close enough to ground level to eliminate all the leaf-bearing parts of stems.

These photos are from a couple weeks after the cutting. The leaves here are those of creeping Charlie. At this point there is no recovery of garlic mustard evident.
It didn’t take a lot of effort to remove a volume of plants with this close-cut variant. In the other plot I cut the plants at around 10 inches above ground level, a height selected to match the practice I have seen used by some restoration workers.
By the time I got around to taking the photos, adjacent garlic mustard plants had completed flowering and were ripening their fruits.
I am giving the test areas several weeks to show any recovery by cut plants, and will share the results in late June.