I wouldn't spray right underneath it -- bound to get some on the sumac. Cleaning or even scraping out the grass and applying mulch would be my suggestion.

get a pump tank.. fill it with water.. and learn how to use it ... by manipulation tank pressure ... that includes how many pumps.. trigger pressure.. and tip adjustment ... practice on cement or blacktop... so you can see the effect ...

gravity dictates that large drop fall to the ground.. you can make those with rather low pressure ...

after that.. apply according to the label ... and just try to hit clumps of grass .. go for about 50% hit rate ... then come back a week later and hit what isnt dead ...

dont try for 100% kill on first try ...

and avoid hitting the plant .. and you should be all set ...

this isnt french perfume.. there is no upside to atomizing it.. and then complaining it drifted everywhere...

i dont know anything about the product.. i use roundup ...

ken

Thanks, gardengal48. I will, but the grass is really tangled up within the shrubs. I guess I'll just start by spraying around it and see if I can hand pull the rest, but I'm not very optimistic! I'm sure heavy mulch would be helpful, too.

also.. when i went at something like this.. i started with a circle about 2 feet out from the plant ... and killed all that.. then methodically... over the weeks.. worked my way in toward the plant ... you might be surprised how interconnected the mat can be.. leaving very little in the interior of the plant.. if you are lucky ...

also ... once you apply a good thickness of mulch ... the soil under will become more fluffy come spring ... i just cant think of the proper term .. friable ... allowing you to pull it out easier in spring ...

ken

https://duckduckgo.com/?q=friable+soil&t=ffcm&ia=web

Friable! That's a new word for me!

hey... you learned something new.. may as well go back to bed for the day ... lol ...

roots need air almost as much as they need water ... so nice fluffy soil can really make a difference ... total lack of air.. would be a bog ...

it also allows deep penetration of water ... for the roots ...

clay is not friable ....

and.. the point was ... you can pull weeds out of fluffy soil ... especially in spring .... much easier .. so you hopefully can get the whole root out.. so you dont have to keep trying to pull out the same weed ...

ken