Bent grass in a Blue grass lawn

by Jeanne
(Minnesota)

How do you get rid of Bent Grass (zone 3) in a lush Blue grass lawn? We have talked to several golf course turf guys and they all say remove all lawn and replace. Whats to stop it from returning?? The expence of replacing with sod is about $5000.00 and they say it is spreading all over the lawn area. It causes large white areas in the spring untill June and then is a light green area all summer. This lawn is irrigated 3 times a week and fertilized/herbicided once a month. Any better ideas?

Doug says that you're creating your own problems with a monthly feeding/herbicide application. You've got such a rich soil and problem area that you're bound to see this problem. I'm also betting you mow fairly low as well and this too makes the problems worse.

Straight up - there is no herbicide registered for control of bentgrass that won't kill the rest of the grass. That's the good news.

But you don't have to replace the entire lawn.

This isn't an uncommon problem with lawns that are intensively managed. In fact, bent grass used to be included in seed mixes (particularly low cost mixes) and is still found as a weed seed in some.

When you see the whitish areas after mowing (scraggling areas when the lawn gets longish), mark the area (surround it with a hose or somthing) let it regrow till it starts to turn green and spray them with an organic herbicide that will burn it to the ground. When it recovers and starts to turn green again, respray with the herbicide - it will go brown again and probably come back one more time. Respray again. When it no longer comes back, you can reseed with your beloved Kentucky Blue.

The key to success is burning off the existing bentgrass multiple times so it doesn't come back. Your problem is that there will likely be a good seed crop in there and the problem may very well reoccur. Good luck.