Killing Grasses Except Blue Gramma
I attempted to reseed my yard with Blue Gramma, following instructions about killing previous turf, etc. But up came weeds and other grasses like crazy, along with the Blue Gramma. In frustration, I let it all grow. Maybe next year I'll try again. Question: Is there any herbicide that will kill all weeds and grasses EXCEPT Blue Gramma? If so, maybe I can save the Blue Gramma I have and try some over seeding this fall. Any advice would be welcome.
Adams County Colorado lawns and turf
As far as I'm aware there is not herbicide available which distinguishes between other perennial grasses and blue gramma. One strategy you can try is to use a product containing glyphosate in the late fall or early spring while the blue gramma it is still dormant. It is a warm season grass so it does not green up until some time in May and is goes dormant shortly after the first frost frost. Many cool season grasses are active much earlier in the spring and later in the fall. Make absolutely sure that you do not see any green blades of the blue gramma (ie that it really is dormant) before spraying.
Once the blue gramma is up and established a selective herbicide containing quinclorac or other products labeled for use on blue gramma or buffalo grass can be used to control broadleaf weeds (always check the label as some selective herbicides safe for use in bluegrass are not safe for blue grama).
After the 1st year a pre emergent herbicide (such as crabgrass preventer) can be used control annual grasses growing in the bluegrama.
The city of Colorado Springs has a good factsheet on the on blue grama lawns which can be found here: https://www.csu.org/CSUDocuments/bluegramabuffaloinstallation.pdf
Sorry I don't have an easy solution for you. The key to keeping weeds in bluegrama or buffalo grass to a minimum is to avoid over watering (after establishment) or over fertilizing.
I hope this helps, please let me know if you have further questions.
I will follow your directions this fall. In the meantime, I will use quinclorac to get ahead of the broadleaf weeds. Then, I will use glyphosate this fall.
I have another question from reading two different sources. One says to use 2,4-D with Blue Gramma (a herbicide used to control weeds in corn), and another says to not use 2,4-D. Since I’m going to use quinclorac and glyphosate, I guess it’s a mute question. But what is your opinion about 2,4-D?
I do appreciate your help.
2,4-D can cause warm season grasses like blue gramma or buffalograss to yellow. The labels of the most products containing 2,4-D say that it should not be used on buffalo or blue grama because of this. I have been told that this damage is worse when the grass is actively growing and not as severe during times when its is not such as the heat of the summer.