I know of nothing that is fescue selective.

Wait until the KBG goes dormant in the winter and spray RoundUp on the green fescue.

I can no longer say that I've never seen you give bad advice, but when you do, it's a duesey.

So you're saying that won't work for KBG and fescue? That method is used all the time for weeds in bermuda.

Heya dchall,

No, for a couple of reasons.

1. Both KB and fescue and rye for that mater, being cold season grasses are on pretty identical biological clocks. So they are going to go into winter dormancy (slowed/stopped top-growth) pretty much at the same time, in fact, I'd guess fescue might before KB. I've never seen KB in Ohio or Pa. turn brown in winter from dormancy. The only time I can recall it going brown was this last winter and it was winter kill from the polar vortex, not dormancy. (lost a lot of plants including ornamental grasses which I think are in the fescue family). Maybe morpheuspa can confirm this (or not). It may work for killing off rye or fescue in bermuda down south because one is a warm season and the other is cool season grass, so two opposite biological cycles?
2. Even if KB did turn brown, the temperatures would be too low for the fescue to be actively growing and the RU would be ineffective.
3. I've never seen any research on fescue winter root growth, but research does show KB continues to grow roots until the soil reaches 32F. So, I'd fear that the RU might possibly affect the "active" KB.
4. Snow cover. :)

I have always wondered based on KB and fescue's different drought dormancy defenses, if you couldn't force (mother nature cooperating) the KB into dormancy and RU the fescue before it went dormant. I've never been that brave.

This post was edited by yardtractor1 on Thu, Jul 10, 14 at 20:25

>>Wait until the KBG goes dormant in the winter and spray RoundUp on the green fescue.

Mostly what YardTractor said, although there are a few considerations.

Not all KBG goes dormant. Mine is supposed to have poor winter color and tolerance, but still stays green in February.

>>So you're saying that won't work for KBG and fescue? That method is used all the time for weeds in bermuda.

Not very reliably on KBG/fescue; they're both adapted to similar temperatures. Even if the blade on KBG has been dropped for the winter, the crown will stay up later partying with its friends since work is done for the year. Spraying will kill the crown, and from there the rest of the plant.

Fescue and KBG mixes have three very specific vulnerabilities (it's actually easier to trim fescue out of KBG).

One is the herbicide Certainty, which hits fescues much harder than KBG, but the line is rather fine and it will damage the bluegrass. I used it to abolish fescue mix from the border between my property and the neighbors' where I couldn't, ethically or legally, renovate. Nowadays the Abbey and Midnight bluegrasses fight it out (the Midnight is winning). I accepted some damage on the KBG as the price for that.

Two is watering. If in a dry period, discontinue watering for 8 weeks. Nada. Not a drop. Most of the KBG will survive and come back when rainfall or watering resumes, most of the fescue will not as it can't go dormant. This is unreliable as it requires Mother Nature to work with you--and she so rarely does (plus eight week droughts are extremely rare in the coastal regions of the northeast, and this year isn't one of them).

Three is feeding. While reliable, it's slow, and what I did on my initial lawn to turn the builder's tri-mix into a halfway decent Abbey bluegrass lawn (that I later tore out for my current elite mix). Feed the lawn at the high-end rate for Kentucky bluegrass, or six pounds of nitrogen per year. I'd say, using synthetics, 1 pound N in each feeding in May, September 1, September 20th, October 10th, October 30th, and you can probably squeeze that last one in around November 10th in Mass, but it's no huge deal if not.

Organically, fire at will, but do try to avoid heavy organics in July and August. If I can't overdo the N organically at 37 pounds per thousand square feet, neither can you.

Fescues object slightly to that much feeding, but mostly it's so the bluegrass is in sharp competition with the fescue--and you're handing the advantage to the bluegrass.

Also, as the fescues inevitably die out (it's a clump grass, after all) the bluegrass rapidly spreads into the open space.

There's really a fifth method, complete renovation to bluegrass, but I'm going to presume that's off the table unless told otherwise.

And a sixth--selective painting with Round Up using a cotton glove or old cloth, but that's tedious, time consuming, and more hassle than most people want to bother with. I did it to a massive chickweed incursion one year, though.

Okay, thanks, y'all. I'm taking notes. I never learn anything when people agree with me.

Only fair. :) I've learned plenty from you, Finally found and read your post on Organic lawn care a while back. Wish you'd update it with your new tweaks.

I painted Roundup onto my Tall Fescue.

It took (2) seasons, but I finally got rid of all of it.

I found a herbicide called Panoramic 2SL. It is labeled to control fescue but is not rated for residential lawns. Has anyone heard of this and know if it is effective on fescue in bluegrass? It is available for purchase online. I have Certainty but it just destroys the bluegrass. I am even afraid to use it with the experiences I've had.