The Lawn Coach: Bentgrass Is Best Left on the Fairway

The Lawn Coach
Bentgrass Is Best Left on the Fairway

Q: I have patches of "bentgrass" in my lawn that are driving me nuts. I've tried to get rid of them, but they keep coming back each season. Weed products don't seem to help, but I've been told that this is a weed.
A: First, let's define "weed." A weed is simply a "plant out of place." If you don't want bentgrass in your lawn (and I can certainly understand your position), then it is a weed. That said, the weed control products you have been trying don't know that.
Bentgrass is generally used as a golf course grass since it does very well under low mowing conditions. In fact, university scientists spend about a gazillion dollars annually to try and develop stronger varieties that can be mowed even shorter without dying. Currently, they're working on a variety that can be cut down to the molecular level so that men in funny pants can roll a ball even faster. These life changing benefits do not extend to creating a great lawn though.
In a lawn, the patches of bentgrass are solid and do not allow for other grasses to encroach. This creates a very spotted, patchy appearance. Here's the thing though; bentgrass (as the name glaringly implies) is actually a type of grass. That said, spraying a weed control product on it would be akin to hunting a deer with a fishhook poked through a squiggling worm. It works well when going for trout, but that doesn't mean that anything in the animal kingdom will fall prey to it.
For bentgrass, you need grass killer. Seeing any difficulties with this yet? A grass killer will also kill the good grass! SO, you'll have to be careful to ONLY SPRAY THE BENTGRASS PATCHES! Let me give two quick pieces of advice that you must take lest you kibosh this entire process. FIRST: When spraying, do not walk through the sprayed spots! I can't tell you how many times I've diagnosed "mysterious" lawn problems that suspiciously looked like footprints leading from a dead patch of bentgrass toward the gate leaving the back yard. SECOND: Make sure that the grass killer is not a "season long" grass killer. Certain products not only kill the grass, but will also make it impossible to grow grass in that area for a full season. These are great for a gravel driveway, but not so much your lawn.
Okay, fast forward 2 weeks. You now have a lawn with patchy brown spots where the bentgrass once was. What should you do? Rip it out? Nope! That's the best part. You probably won't believe this until you see the end results, but here's one of the coolest things I've yet seen in a lawn. All you need to do is rent a core aerator (which many rental places have) and run over the dead spots a few times to create a bunch of holes through the dead mat. Then sprinkle some seed generously throughout and scratch the whole area a bit with a rake to mix it up. If the patches get consistent water, you'll be able to watch the new grass grow through the holes and fill in the area. The bentgrass will completely die off and the new stuff will take over in just a couple of months.
When done correctly, this procedure will rid your lawn completely of the unwanted bentgrass and you can enjoy a non-polka dotted property once again.

You can visit me on the web at http://TheLawnCoach.Blogspot.com or email me at TheLawnCoach@aol.com. Check out past columns, send in your questions, or even photos and videos of your lawn problem!