I used to mow / bale hay when I was a teenager. I used a sickle type mower, think that would work for you?
What I've been leading up to is I don't think you really want to "kill" the Bahia. Realize if you do truly kill it Mother Nature will grow something else in it's place that will be as much if not more of a problem and probably be more unsightly. I'll tell you a story in a second.
What I really think you want to do is:
#1 get the grass down to a reasonable height. This might be easier done when the grass goes dormant or as dormant as it's going to get.
#2 From a chemical standpoint what you want to do is regulate the growth aka slow it down. You could do this with very light applications of the mentioned Glyphosate or MSM (Metsulfuron). If there's St. Aug present the MSM wouldn't harm it and at those light rates it shouldn't harm the Oak trees.
Here's the story:
There was this guy, kind of a deekhead, want me to spray his yard with my magic juice aka weed control. I checked the yard out and determined his yard was mainly what I would classify as weeds, Bahia and other wild stuff. Most of the nice yards in my area are St Aug or Centipede like your area. I told him I didn't advise spraying his yard as it would only open the door for a host of other even less desirable things. He kept on and on and I would explain it over and over. I finally did it just to shut him up and give him what he deserved. I sprayed it and just as I predicted Mother Nature unleashed a multitude of Plants, what we call weeds. Looked like sheet BTW. He proceeded to tell me I didn't know what I was doing and would tell everyone how incompetent I was. I reminded him of my earlier statements and predictions. I made sure to do this all on text so I would have a record of every conversation.
Hope this helps.
Good luck with your battle with cancer
Thanks for the input and especially for the well wishes and concern, that really means a lot to me.
I have thought about what might happen if all dies. It can't look any worse than it does now man. And I'm not concerned with how it looks if it's short. I don't have a neighbor for miles, only cows. I care about it getting too overgrown for me to be able to handle it personally, even if I am in good health at some point. If I get to where I have 4inch diameter stuff growing in there, then it is beyond my capability to mess with in terms of my equipment.
Basically I am trying to make this the least possible burden for someone else i if I can't tend to it after my treatment is over.
That is why I just want to go Agent Orange onall of it. If it got down to dirt, that is the best case scenario. No other weeds can be harder to eradicate or more unsightly than this crop of bahia. And it's density prevents me from getting in the middle of to cut down the saplings and woody stuff that is getting bigger by the day.
I absolutely don't care one iota what it looks like after spraying, which is why I wouldn't think twice about burning it if it weren't for the structures there.
I just want it gone at any costs and will deal with the consequences later. My original plan was to spray it multiple times per year and after the spraying, till it under about 6 inches to elimnate the rhyzome mat and eventually get rid of it all that way.
My health just isn't up to that much time in the tractor seat right now, but hopefully after my treatment I will pursue that same method. Right now, I am severely out of breath after I take a sip of water from a glass and super fatigued. That is the main symptom of the type of cancer I have.
So I am just trying to buy time. There is nothing more that I want than for this stuff to be DEAD AND GONE, at least for now. If I am in shape enough to tend to it next spring/summer then so be it.
But I don't want it progressing any further and if something happens to me, a member of my family will have to pay someone to come out there and clear the land with a skid steer mulcher/dozer in order to sell my house. I am trying my hardest to avoid putting someone in that position.
I am open to just keeping it stunted with Gly, but it has to be knocked down first, it is beyond that point. I have looked into the calculations for that but I don't know what I did with my numbers.
There was actually a lawn company here that had rigged up a system to secretly spray a light application of Gly under his deck. He had a contract to spray pumping station etc out in the middle of nowhwere for oil and gas companies, but they specified that he not use Gly.
These are just fenced in areas with pipes rising out of the ground in the middle of the swamp basically, so I don't know why they didn't want him to spray. Anyway, I thought that was a funny story.
Lol I know jerks exactly like you are describing. You do exactly what they want after you try to protect them from themselves and then they get mad at you lol. Sorry you had to deal with that.
Honestly a heavy duty flail with hammers vs knives and mainly better wire protection than the one I have would solve all of this with no spraying necessary.
My flail was doing great until the bahia got sucked into the bearings. There just isn't a guard on mine or any way that I can fabricate one based on how this thing is put together.
But there are some modern ones that have a concentric pieces of pipe/metal surrounding the cuttershaft to prevent foreign stuff getting in there.
If I had one of those, problem solved...even if I am too sick to drive the tractor I could get a buddy to do it. But I don't have type of mower and can't afford it.
Regarding the sickle, most hay guys around here have abandoned them due to maintenance. There are so many anthills around here and apparently they dull the sickle mowers up pretty quickly.
Most guys around here use disc mowers. I have contemplated getting a drum mower, which would be great for this and cheaper than the flail plus low maintenance. There are 2 guys on craigslist here with Kuhn PZ flails that are pretty ancient and reasonably priced, but they are not responding.