Won't be pretty but it will work. Put black plastic over it until it's dead--at least a year, probably no more. If it can't photosynthesize, it will die.

Thanks Lacey, I’ll pass it on. Sounds like he’ll want to try chemicals though

i dont understand what A/c pipes or wires would be underground ... they go thru the wall usually ...

and you dont kill a plant by poisoning the ground .... unless you misapply the plant killer by not using it according to label instructions ...

ken

The city will come out and mark any underground pipes &/or wires. ("Call before you dig.") It might be a good first step to do that. Then if you discover it's OK to dig, the quickest solution is available, dig this stuff up.

Boiling water would kill it, but such a large patch would take several large applications. Cutting as much debris away as possible, and then chopping down into the crown (an inch or two, to not disturb supposed wires) in several places would enable more of the deadly hot water to reach the crown & roots.

I used round up to kill mine.

Thanks guys, I’ll let him know all these suggestions.

I honestly don't think boiling water will kill this. In my experience getting the water out into the garden while still boiling and in quantity is really difficult. It starts to cool the second it is taken from the heat source and the act of pouring cools it further. And I was only trying it on dandelions. A large tough clump of grass like that wouldn't bat an eyelid, unless you have a way of producing large volumes of boiling water right on the spot. I'd dig it out. But if you choose herbicide wait until the grass is in vigorous growth.

Thank you! I wondered that as well, having both killed much smaller things w boiling water and also dug up these types of grasses. I’ll pass it on!

you could use vinegar. How to Kill Ornamental Grass (sfgate.com)

Flora, I am not sure why you've decided to disagree with everything I say, even the word "similar" in a recent discussion. What's up with that?

Agree with Flora. Boiling water most definitely will not work on that huge grass.

I haven't been able to get boiling water to kill anything. Lawnmowers, OTOH, can be very effective. It can take a while, but is very easy.

mad gallica has definetely a point, those kind of plants are not adapted to frequent disturbance, in that case mowing. if you keep cutting it as soon as it is mid shin/ under knee high,

it will probably give up within one season or perhaps try a weak go next season

I’ll pass it on! Thanks :)

cover it with rock salt. not poisonous & will dissipate in a year. ( i do not kill dandelions, i plant them. early forage for honey bees. )