controlling annual bluegrass

[Chas Hurst]

Is there a selective herbicide that controls annual bluegrass growing in perenial bluegrass?

[Eggs Zachtly]

Not that I've ever heard of. I called a spray tech from work, and he said the same thing.

[KC]

I don't have any experience with bluegrass, but I have to ask the question anyway: If annual bluegrass comes back every year from seed, why wouldn't a preemergence control it without harming the perennial?

KC

[Steve]

Pre-e will help somewhat but timing is everything. I use it in August for poa control here in northern Ohio. You have to be careful to stay away from bentgrass with it, and not to apply too much for fear of root pruning on your desirable turfgrass.

You have to apply it after the poa dies back and before it re-germinates, which is generally late summer.

[Eggs Zachtly]

Which then leaves the dillema that you then can't reseed the perennial bluegrass, in the fall. The pre-emergent doesn't care who's seed is trying to poke through the barrier.

Poa annua sucks. I can't imagine trying to rid it from a lawn of P. pratensis. They're the same genus. Even /if/ such a selective herbicide were available, being species-specific would put it well out of reach of a homeowner, both in cost as well as by government regulations.

[Steve]

Yep, between a rock and a hard place to control it, I've heard guys trying growth regulator on it with some limited success too. One of these days a better control will be available and the cash cow will come home to someone like Monsanto or Dow or who knows who..

[NoMoreRGS]

Some info that I have found but have not tried (two snippets). You may be able to google and find it also. ================================================== Poa Annua- Is it yellowish-green? Does it die out under drought conditions? Then it's probably poa annua, or annual bluegrass. If so, then your gardener is on target -- control is very difficult -- but not impossible. Some folks have success with preemergence herbicides (such as Scott's Turfbuilder Halts Plus for crabgrass control), but the application must be timed right; it's probably already too late to do anything about it this year. There is a postemergence product that has been on the market for a couple of years called ethofumesate (tradename Prograss) that is very effective. However, it is available only to professionals; it might not even be authorized for use on residential lawns. ================================================== Abstract: The postemergence herbicide ethofumesate and the plant growth regulator paclobutrazol were evaluated for annual bluegrass control in creeping bentgrass turf managed as golf fairways. Both products were applied under several different timing regimes relative to the time of the year. Paclobutrazol treatments provided significantly greater annual bluegrass control than ethofumesate. There were no differences between rates of paclobutrazol (0.28 and

0.14 kg ai/ha) when applied from spring through summer. Annual bluegrass control after spring and summer applications of paclobutrazol was 85% or more. Clipping weight data indicated that paclobutrazol suppressed growth in annual bluegrass longer than in creeping bentgrass. It was concluded that prolonged suppression of annual bluegrass by paclobutrazol resulted in creeping bentgrass dominance and subsequent annual bluegrass control. Additionally, applications of ethofumesate in autumn?winter, followed by paclobutrazol applied in spring?summer, provided significant control of annual bluegrass in 1 yr of the study.

Nomenclature: Ethofumesate; paclobutrazol, (±)-(R*R*)-ß-([4-chlorophenyl]-methyl)-a-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; annual bluegrass, Poa annua spp. annua L., spp. reptans Hausskn. #3 POAAN; creeping bentgrass Agrostis stolonifera L. ?Penncross?, ?Providence?. ====================================================

[Steve]

No one said it was going to be easy! Good info, NM, thanks for sharing.