Stilt grass

Stilt grass (Microstegium vimineum): the green grassy meadows in low woods, the mats hiding in lawns, the long thin threads with grassy blades winding through plans in the garden. When I grew up in North Carolina, there was nothing like it. As I visited family over the years, I began to notice it, wonder about it, and then worry about it. Now that I have my own piece of land to steward, I plan and strategize, looking for allies.

Here in North Carolina, now is the time to think about how you can keep plants from setting their seeds. Mechanical removal now into mid September can keep the plants from setting seed: mow, pull, swing a weed blade, wield the weed whacker. Yesterday, during my weeding, I found ferns and columbines persisting underneath the towering plants. And, since there’s so much biomass, the piles look really big in a short time.

Mechanical methods seem effective to me, but for those who are comfortable with better living through chemistry, there are some suggestions from NC State: https://projects.ncsu.edu/goingnative/howto/mapping/invexse/japangra.html .

Once you’ve dealt with this year’s growth, make plans to prevent the seeds in the seed bank — viable for five years or so -- from germinating in the spring. Last fall I laid a thick layer of pine straw in some areas and found that the stilt grass did not germinate there. I had also seeded with oats as a cover crop in some places: the oats did seem to hold back the spring growth of the stilt grass, and where I left the oats as mulch, I have only recently had stilt grass sprout.

I’ve noted that the tall perennial sunflower family plants Bear's Foot (Smallanthus uvedalius) and Southern Crownbeard (Verbesina occidentalis) have lush enough growth to smother out stilt grass. They grow well along the edge of woods to open area, and are loved by pollinators, seed eating birds, and I have even seen hummingbirds feasting at the small flowers of the Bear's Foot. Bear’s Foot is in the same genus as the edible South American tuber, Yacón (Smallanthus sonchifolius). Crownbeard is closely related to the edible and native Jerusalem artichoke or sunchoke (Helianthus tuberosus) and sochan or cutleaf coneflower (Rudbeckia laciniata). My attempt with sunchokes was met by enthusiasm by deer, so I did not establish plants that could stand up to the stilt grass.

Another native edible I tried was ground nuts (Apios americana). These did not take to my area, which is possibly more dry than where they might thrive. Still grass won there.

I have yet to visit some areas back in the woods where i tried to find some other allies. In one area I planted the domesticated yellow nutsedge (Cyperus esculentus), chufa. Unlike the pest-plant, chufa is sterile and the tubers do not survive freezes. Chufa is used as a food plot plant for turkey, so if it thrives and were to persist through the winter, the benefit of offering a habitat plant for turkey would be wonderful. I also spread seed from Seminole pumpkins, a very mildew resistant traditional variety of butternut squash (Cucurbita moschata). They're thriving in the partial shade near my compost, so it's conceivable they might have spread out back where the stilt grass grows thickly. Next year i might fertilize when i plant seeds in the woods.

In my planning for this coming year, I’m experimenting under black walnuts, under which stilt grass thrives. I’ll seed oats as a “nursery crop” for a native vetch, Canada Milk Vetch (Astragalus canadensis). The standard cover crop vetch matures in late spring, but Canada Milk Vetch blooms into August. With luck it will be thick enough to smother out stilt grass. Then i can cut it back in September to find the black walnuts (if the squirrels leave me any).

I’d live to hear other folk's strategies for dealing with stilt grass.

Cheers,
Judith


https://ncwildflower.org/plant_galleries/invasives_list
https://content.ces.ncsu.edu/japanese-stiltgrass-identification-and-management
https://projects.ncsu.edu/goingnative/howto/mapping/invexse/japangra.html
https://plants.usda.gov/core/profile?symbol=MIVI

This plant continues to blanket state parks woodland in my area. Thanks for the information.
I had a patch of it in my yard under trees last year, pulled much of it, and chicken scratching seems to have kept it from recurring.