When to Apply Poe Annua Pre-Imergent - Ask Extension
Both Scott's Halts & Bonide Weed Beater Complete state to apply their product in August or September depending on soil temperature to fight next y...
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When to Apply Poe Annua Pre-Imergent #867524
Asked May 08, 2024, 9:10 AM EDT
Both Scott's Halts & Bonide Weed Beater Complete state to apply their product in August or September depending on soil temperature to fight next year's growth of this grassy weed. What does MSU Extension say is the best time to apply this pre-emergent in the Detroit area?.
Macomb County Michigan
Expert Response
Gerard, can you send photos of the weed? Please include a landscape scale and some close up photos.
Thank you :)
Thank you :)
I misspelled it. It's Poa Annua. If you have a smartphone or send to a smartphone, you can make the picture bigger with the printing. I know it's poa annua.
Gerald, I usually recommend August in our area for preemergent applications to control winter annual weeds.
As far as I know we do not have any herbicide resistance to these products in our state thus far.
The biology of annual bluegrass is a little fluid. While it is called "annual" bluegrass, some populations can actually exhibit a perennial lifecycle. You can read more about this and other annual bluegrass issues from this MSUE document: https://www.canr.msu.edu/ipm/diseases/annual-bluegrass?language_id=
If you have a perennial population, then a preemergent herbicide will not control what is there, but could still be helping prevent more individuals from coming up from seed.
If you want to see how your plants are behaving you could flag a couple plant (clumps) and see if the mother plants die back in the next couple of months. If they do not, then you're dealing with a perennial population.
If you have a perennial population there are no chemical options that will not injure your desired turf species, so a broadspectrum herbicide, like glyphosate would be needed and then those areas would need to be reseeded.
Please let me know if you have any questions.
As far as I know we do not have any herbicide resistance to these products in our state thus far.
The biology of annual bluegrass is a little fluid. While it is called "annual" bluegrass, some populations can actually exhibit a perennial lifecycle. You can read more about this and other annual bluegrass issues from this MSUE document: https://www.canr.msu.edu/ipm/diseases/annual-bluegrass?language_id=
If you have a perennial population, then a preemergent herbicide will not control what is there, but could still be helping prevent more individuals from coming up from seed.
If you want to see how your plants are behaving you could flag a couple plant (clumps) and see if the mother plants die back in the next couple of months. If they do not, then you're dealing with a perennial population.
If you have a perennial population there are no chemical options that will not injure your desired turf species, so a broadspectrum herbicide, like glyphosate would be needed and then those areas would need to be reseeded.
Please let me know if you have any questions.
