Invasive grass species eradication - Ask Extension
Hello
My lawn was sodded about 14 years ago. I have always tried to take care of it with timely watering, fertilizer, core aeration and thatch remova...
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Invasive grass species eradication #804863
Asked August 05, 2022, 5:51 PM EDT
Hello
My lawn was sodded about 14 years ago. I have always tried to take care of it with timely watering, fertilizer, core aeration and thatch removal. Over the years ( my lawn was once the envy of the neighborhood) I’ve been getting these patches of very dense fine bladed grass that browns quickly without water that in order to keep green requires sprinkling that I am finding unaffordable. It is so dense that trying to get a rake through it is nearly impossible. I’ve tried overseeding but without ripping through it so the seeds can reach the soil it’s been a waste of money. Can you help me identify the grass variety, suggest a way to minimize its spread and also get rid of it short of digging it out?
Btw the photos attached reflect the fact that I have not irrigated the lawn very much in July and we haven’t had much rain. The only areas that this invasive grass is still green is near the sprinkler heads.
Oakland County Michigan
Expert Response
Rebecca K,
Something might (still) be wrong w/ Ask Extension because I opened this question and it took several minutes
to see the photos that were attached but I couldn't open them. Nor could I type in any reply. Closing the site
and reopening didn't improve the problem. Help!
Dick Moldenhauer
Dick Moldenhauer
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From: Ask Extension <<personal data hidden>>
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Sent: Mon, Aug 8, 2022 11:49 am
Subject: Question assigned to you (#0074794)
Hi Dick,
Question #0074794 has been assigned to you by rebecca k.
Invasive grass species eradication
Hello My lawn was sodded about 14 years ago. I have always tried to take care of it with timely watering, fertilizer, core aeration and thatch removal. Over the years ( my lawn was once the envy of the neighborhood) I’ve been getting these patches of very dense fine bladed grass that browns quickly without water that in order to keep green requires sprinkling that I am finding unaffordable. It is so dense that trying to get a rake through it is nearly impossible. I’ve tried overseeding but without ripping through it so the seeds can reach the soil it’s been a waste of money. Can you help me identify the grass variety, suggest a way to minimize its spread and also get rid of it short of digging it out? Btw the photos attached reflect the fact that I have not irrigated the lawn very much in July and we haven’t had much rain. The only areas that this invasive grass is still green is near the sprinkler heads.
From: bobsolak
Submitted: 08/05/2022 5:51 PM
Submitted: 08/05/2022 5:51 PM
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So have you fixed the problem?
The system problem seems to have gone away.
I'm not able to make a positive identification of the 'rogue' grass in your lawn from the photos. I suspect it may be creeping bent grass (Agrostis palustris) or maybe roughstalk (or rough) bluegrass (Poa trivialis). Here are some links to more info on both species and their control:
https://www.canr.msu.edu/ipm/diseases/creeping-bentgrass#gallery
https://plantscience.psu.edu/outreach/plant-id/grasses/bentgrass_creeping
https://u.osu.edu/athleticfieldmanagement/2017/04/06/selective-creeping-bentgrass-control/
Weed-Rough Bluegrass (Poa trivialis) -IAState
https://turf.purdue.edu/roughstalk-bluegrass/
http://misin.msu.edu/facts/detail/?project=misin&id=465
https://extension.psu.edu/roughstalk-bluegrass-a-cool-season-perennial-grass
Both of these grass species are difficult to control except by physical or chemical removal. Physical removal needs to go beyond the visible boundary of the current growth. Chemical removal is best accomplished by proper use of glyphosate.
When using products containing glyphosate there are a few important points to consider. First, as with any pesticide, remember to read and follow all labeled instructions. Second, glyphosate is a broad-spectrum (non-selective) herbicide, meaning it will injure or kill other plants contacted during application, so care is needed to avoid green plant material, exposed roots, and injured bark of desired plants (it will likely be unavoidable to kill some of the desirable grass in this case). Third, glyphosate is relatively safe in the environment when used as labeled. It adsorbs strongly to soil in most cases (i.e. clay and organic matter), allowing even sensitive crops to be planted shortly after application; meaning no carryover issues are expected. Fourth, glyphosate alone can take up to 14 days to show full activity under ideal growing conditions. Retreatment of the area may be needed depending on the degree of infestation. Glyphosate is most effective for perennial control in the fall but can be applied anytime the plants are actively growing (temperatures consistently above 50F) and not under stress (e.g. hot, dry conditions). Finally, be sure that the product you choose has only the active ingredient glyphosate or glyphosate + pelargonic acid. Products with additional active ingredients may have other unwanted effects and may delay the planting of other plants in the coming season(s).
You should be able to get a positive identification by contacting MSU Plant & Pest Diagnostics at:
https://www.canr.msu.edu/pestid/
You should be able to submit photos for the identification. I'd include a 3rd close-up photo of the turf, dug out of the lawn, soil brushed off the roots and laid on a white sheet of paper for their use. If you do have MSU P&PD identify your rogue turf, I'd appreciate it if you would please send me an email with their answer so I can learn too. Their email is: <personal data hidden> and the office phone # is 517.355.4536
I'm not able to make a positive identification of the 'rogue' grass in your lawn from the photos. I suspect it may be creeping bent grass (Agrostis palustris) or maybe roughstalk (or rough) bluegrass (Poa trivialis). Here are some links to more info on both species and their control:
https://www.canr.msu.edu/ipm/diseases/creeping-bentgrass#gallery
https://plantscience.psu.edu/outreach/plant-id/grasses/bentgrass_creeping
https://u.osu.edu/athleticfieldmanagement/2017/04/06/selective-creeping-bentgrass-control/
Weed-Rough Bluegrass (Poa trivialis) -IAState
https://turf.purdue.edu/roughstalk-bluegrass/
http://misin.msu.edu/facts/detail/?project=misin&id=465
https://extension.psu.edu/roughstalk-bluegrass-a-cool-season-perennial-grass
Both of these grass species are difficult to control except by physical or chemical removal. Physical removal needs to go beyond the visible boundary of the current growth. Chemical removal is best accomplished by proper use of glyphosate.
When using products containing glyphosate there are a few important points to consider. First, as with any pesticide, remember to read and follow all labeled instructions. Second, glyphosate is a broad-spectrum (non-selective) herbicide, meaning it will injure or kill other plants contacted during application, so care is needed to avoid green plant material, exposed roots, and injured bark of desired plants (it will likely be unavoidable to kill some of the desirable grass in this case). Third, glyphosate is relatively safe in the environment when used as labeled. It adsorbs strongly to soil in most cases (i.e. clay and organic matter), allowing even sensitive crops to be planted shortly after application; meaning no carryover issues are expected. Fourth, glyphosate alone can take up to 14 days to show full activity under ideal growing conditions. Retreatment of the area may be needed depending on the degree of infestation. Glyphosate is most effective for perennial control in the fall but can be applied anytime the plants are actively growing (temperatures consistently above 50F) and not under stress (e.g. hot, dry conditions). Finally, be sure that the product you choose has only the active ingredient glyphosate or glyphosate + pelargonic acid. Products with additional active ingredients may have other unwanted effects and may delay the planting of other plants in the coming season(s).
You should be able to get a positive identification by contacting MSU Plant & Pest Diagnostics at:
https://www.canr.msu.edu/pestid/
You should be able to submit photos for the identification. I'd include a 3rd close-up photo of the turf, dug out of the lawn, soil brushed off the roots and laid on a white sheet of paper for their use. If you do have MSU P&PD identify your rogue turf, I'd appreciate it if you would please send me an email with their answer so I can learn too. Their email is: <personal data hidden> and the office phone # is 517.355.4536
