invasive grass

Asked May 13, 2013, 9:58 PM EDT

Last year we moved onto a new property for us. We used the garden space used by previos renter. There is an invassive grass in the garden. It took over, it was the most pitifull garden ever. So we sprayed round up in the fall, and again 2X this spring, tilled 2x and yet the roots to this grass are plentifull. How do I deal with this?

Multnomah County Oregon weed issues horticulture

1 Response

Good day, and thank you for using Ask an Expert.

It sounds like the grass is a perennial with extensive and sturdy roots. So I suspect tilling has made things worse by cutting the roots into smaller pieces, each of which grow.

Our first task to get rid of that grass is to identify it. You can attach up to 3 images when you reply to me. Most helpful are an overall view of the site; an image or two of an entire grass plant, roots included (if the grass is quite tall, one of the top half, another of the bottom half with roots); and the flower head.


The general strategy to use against a perennial of any kind is to starve the root system. It’s helpful to begin the process by physically removing as much of the plant as possible. Then, top growth must be removed every time it’s aboveground, perhaps on a weekly basis. You will need to repeat this action a number of times, perhaps over several years.

I look forward to receiving your images so that we can get your project underway.