Japanese stiltgrass

Asked June 8, 2020, 10:10 AM EDT

Hello - can you tell me if this is Japanese stiltgrass? I know it’s terribly invasive and clearly happy in my backyard bog. Is there an equivalent of yellow rattle that destroys grass roots that I could plant to try and start the battle to get rid of the stiltgrass? Is there a native false indigo that might work? I want plant things that might help with the task!

Anne Arundel County Maryland

1 Response

There are at least two different plants on the notebook paper, but neither appears to be Japanese Stiltgrass. In the other photo, we cannot clearly see any identifying features to determine if some of those plants are Stiltgrass or not; some are definitely not, but we cannot identify all of them. You can compare characteristics of the various weeds with this information on Stiltgrass: https://extension.umd.edu/hgic/topics/japanese-stiltgrass. The silvery midrib is fairly diagnostic, as is the easy-to-pull root system. Varied control options are given below the ID features.

There are many native and non-invasive plants that could serve to populate this soil after the weeds are removed, and they will help out-compete any Stiltgrass or other unwanted plants. However, we are not aware of any that actively cause the dieback of Stiltgrass through allelopathy or similar means. Choosing replacement plants best suited to this environment (shaded and wet) will meet the most success, rather than trying to alter the soil to the liking of other plants. Some options among native plants include Summersweet (Clethra alnifolia), Turtlehead (Chelone glabra), Sensitive Fern (Onoclea sensibilis), Great Blue Lobelia (Lobelia siphilitica), Blue Flag (Iris versicolor), and Winterberry Holly (Ilex verticillata). You can plant spreading, lower-growing perennials (like the fern) at the base of taller, leggy shrubs (like the Winterberry) for example.