The dry season can be a good time to remove first-year Herb Robert. In the dry season there can be many small Herb Robert plants, still green, that just germinated during the growing season and will likely not flower until the following year. I find that sometimes these first-year plants are not yet firmly rooted and can be removed fairly easily. I’ve even had good success with a leaf rake on patches of these small Herb Robert plants when they were growing on top of several inches of loose, dry leaves.
Herb Robert is easy to spot during the dry season after the look-alike native, Pacific Bleeding Heart has died back.
I find that Herb Robert can germinate and start to grow on top of duff or mulch with little or no soil. Then, over the course of the wet season, as the duff decays and dissolves into the soil, the Herb Robert spreads its fibrous mass of roots into the very top layer of the soil. I am often surprised by how extensive that root system can be when I remove plants that have wintered over. Removing them then, can disturb a patch of ground as large as a dinner plate.
Yesterday, as I worked on Herb Robert, the words, “It’s the Button, Bob” came into my head. If you’ve had experience with Herb Robert, you know that it’s sometimes called “Stinky Bob” because of it’s unpleasant odor. And the button? That’s what I call the small disk at the base of the plant where the stems converge. When I remove Herb Robert I push the plant to one side to find the button, get a grip on it, and wiggle and pull the plant out of the ground. Also, finding the button assures me that I’m not removing a Bleeding Heart.
Another advantage to removing the Herb Robert now is that these first-year plants are not as likely to start blooming and go to seed if they are added them to a compost heap.
And what about using a leaf rake on large patches of first-year Herb Robert. I’m still experimenting, but it may work when the plants are very small and growing thickly on top of a good layer of leaf litter. I raked some yesterday in an edge area of about 50 square feet next to some pavement. I’ll learn how well it worked when I come back to the same area next year.