"Joe C (free agent acct)" wrote
I battled it for years until I found this cure.

when the shoots come in the spring, let them get 8-12" high.
Then get a long metal drill. Break off the shoot and then drill down
the center unti you hit some resistance. Then drill about 1/2"
further. Now pour a teaspoon of Roundup in there - Wham!!!
That will kill the shoot and the root underneath. This works!!!

I'm told that spraying new shoots with Roundup in the usual way does
much the same thing: dead shoot, dead section of nearby rhizome, but
little chance of killing more than that unless one sprays all the shoots
and culms. My best kills of weeds using Roundup have always been
when I let a weed get big and then spray all of its foliage, so I'd simply
wait until a culm grows to full size and then spray its leaves all over.

Remember that Roundup is eaten swiftly by soil bacteria, so a lot of it
will go to waste if you pour it down holes.

Mark., but whatever works for you