What is this weed?

Question: Every year about this time this weed appears in my yard. With the lack of rain there are lots more of them this summer.  Would like to know what the name is and what I can spray them with to kill them but not harm my grass.

responder: Steve Miles  Master Gardener, Hennepin County MN (I answer using human intelligence, not AI)  Replied July 19, 2023, 2:21 PM EDT
response: Thank you for writing. I have lots of spotted spurge. It seems easy to pull out but leaves root fragments that regrow.  https://www.minnesotawildflowers.info/flower/prostrate-spurge#:~:text=The%20only%20other%20hairy%2C%20mat,surface%2C%20and%20seed%20lacks%20conspicuous

responder: The Question Asker Replied July 19, 2023, 2:40 PM EDT
response: Thanks for your quick reply. Please confirm I can spray these pesky weeds with a typical post emergent herbicide. I have some Spectracide Weed Stop for lawns concentrate on hand and I think this will do the trick. On Wed, Jul 19, 2023 at 1:21 PM Ask Extension <<personal data hidden>> wrote:

responder: Steve Miles  Master Gardener, Hennepin County MN (I answer using human intelligence, not AI)  Replied July 19, 2023, 4:00 PM EDT
response: Thank you for writing. There is no specific herbicide for spotted spurge.  Spectracide has multiple active ingredients. This is the official toxicity analysis.   https://t8u6c2z7.stackpathcdn.com/~/media/HomeAndGarden/Spectracide/Files/SDS/SpectracideWeedStopforLawnsConcentrate<personal data hidden>5SDSAug21.pdf  One may expect that many non-target plants will be affected if this is not applied carefully on a dead calm day.  This is called herbicide drift and will affect flowers and edibles alike. https://extension.psu.edu/herbicide-drift-and-drift-related-damage Follow the directions especially for dilution and intensity of application.   One may expect this will be toxic to life forms that live in water including fish and frogs.   i do not understand why the spurge is sitting in such a dead patch. Correcting the conditions which led to spurge invasion might be more effective and more pleasing than a herbicide.

responder: The Question Asker Replied July 20, 2023, 9:07 AM EDT
response: I am dealing with a strip of grass between the sidewalk and the street. This area has really poor soil and the grass quickly goes dormant when it gets dry. I was planning to remove all the grass and about 4” of dirt in this area this year and replace it with good top soil and new grass. Felt it best to postpone this project due to the drought conditions this summer. The spurge is starting to really thrive in the current conditions so I figure it would be good to knock it down. Your advice about overspray and impact on life forms is well taken. Given where this spurge is located I believe applying selective herbicide will be OK.  Steve in Forest Lake,MNOn Wed, Jul 19, 2023 at 3:00 PM Ask Extension <<personal data hidden>> wrote:

responder: Steve Miles  Master Gardener, Hennepin County MN (I answer using human intelligence, not AI)  Replied July 20, 2023, 11:22 AM EDT
response: Thank you for writing back. Lets think through the sod part. Most sod contains mostly Kentucky bluegrass which is the frailest of grasses and takes large inputs of water and nutrients etc.  https://extension.umn.edu/lawn-care/seeding-and-sodding-home-lawns https://turf.umn.edu/news/eric-watkins-turfgrasses-minnesota-lawns This site is also susceptible to salt damage from winter plowing. In fact, it may be that salty soil and drought and sun are what killed the grass.  You would do better with a tougher, more drought resistant grass such as category 1.  The fescues are seriously drought resistant. https://extension.umn.edu/lawn-care/renovating-lawn-quality-and-sustainability You can get these at any good garden center or even but some grasses and mix them up yourself.  Ultimately it will be survival of the fittest-my guess is that the fescue will reproduce better.  Finally, lawns should be cut no shorter than 3.5 to 4 inches.  The taller the grass, the deeper the roots. The deeper the roots, the more resistance to drought, weeds and also for leaving a space that works for Japanese beetle slugs.