Could this be phragmites ?
My neighbor has a field next to a farm and a single clump of this grass showed up this year. It's between 6-8 feet tall and the crown is approximately 2 feet square. The field is not particularly wet. We want to know if we should try to remove it before any more seeds drop. Or is it too late ?
This is miscanthus, another ornamental grass that has escaped and is now invasive. It does not require the damp soil which phragmites prefers (though phragmites can grow very nicely without damp soil.)
Miscanthus can also be highly invasive in Eastern shore wetland (but not always wet) soils.
Some miscanthus species are supposed to ripen seed later and thus the seed is not supposed to mature and be a problem. However, with our longer seasons of warm weather, and rampant hybridization, all bets are off for miscanthus.
We recommend that you dig it up as soon as possible, or spray just the base with glyphosate when it is green. Keep an eye out for more seedlings, as there must be one parent plant in the area that is producing mature seed and more seed will be on the way unless that parent is eliminated.
If possible, locate and eliminate the parent plant. Alert neighbors.