I'm trying to devise a plan for killing the briars around the 5 acres my house sits on. Do briars have a formal name? Trying to find the best way to research this on google is tough partly because the word briar seems too general. I know Roundup would work but I don't want to kill everything in some of the spots, & the briars are in a tough spot to mow, yet quite tall to safely spray some of them. I want to treat them at the right time of the year too. I could disc trim 'em but they'll probably grow right back. 1 year I tried pulling them & that didn't work. Some are so big I'm leaning towards snipping them at ground level & putting garlon on the cut 'stump.'

Greenbriar, tough little plant, hate those little spikey needles, hard to kill, I cut them off close to the ground and Round-up the stump.

You said it...You need a scientific name. Post a photo at least. Once we know what you are trying to manage, you might get some better advice.

We call them briars or brambles. 'Rubus'. They're basically a 'rose' family member.

Ammonium Sulphamate seems good on them. Doesn't seem to bother grass either, unlike glyphosate.

Granted, it's early days for my experiencing it. But, I sprayed some on and gave it a week or so. They looked Bad! Practically black! Leaves And stems!

I've now brush cut those out the way and am considering my next move. Continue trying to spray / cut? Wouldn't really be an option with acres to deal with.

Or, might I wait till they die back a little, with winter. Brush cut my way through them. Heap and burn. Then walk about spraying the short stuff left behind?

Murderous things.

Multi flora rose by any chance? Nasty stuff to deal with but the critters like to eat the berries and deer hide in there.......jk

I think I know what AJE is talking about. I would feed the briars to goats. I don't think herbicide works that great long term . Just my 2 cents.

You can try searching the word Smilax, it is the genus for many different species collectively called greenbrier. Rubus is the genus for blackberries/brambles, and Rosa is the genus for roses. Hopefully one of those three can help narrow it down for you.

If you don’t already have it, there’s a free app called “Seek” that uses your smartphone camera to identify plants & animals. It’s been helpful for me.

Use Crossbow herbicide on them!

I don't like broadly spraying any herbicide on an area that isn't just one type of plants. I want to kill one specific plant, not everything that is growing there so I target the pest plant.

If you kill everything you open up the area for invasion of undesirable stuff, like thistles, buckthorn, garlic mustard and so on.

I'm not sure what OP means when he says briars. I have lots of blackberry bushes in my woods that can be very aggressive and they take over any area that has any significant amount of sunlight.
I snip them an inch or two above ground height and then treat the stump with a 20-30% concentration of glyphosate. I use this also for any other plant that I come across that I want to get rid of like Autumn Olive, Multi-flora Rose, Mulberry, Bush Honeysuckle (there is a native honeysuckle vine that is good), Burr-docks, certain thistles (not all thistles are bad) and so on. It works pretty good. This can be very time consuming and its a pain, literally the scratches can be painful at times, for thick areas of blackberry but once done they don't come back as long as you seed the area with something else or have something else growing there that can keep the black berries from coming back.

At other times when a plant is smaller and has just a few leaves I will use a mix of foaming agent, dye and glyphosate and use a dispenser that puts out a foam (like shaving cream) right on to the plants leaves. There is zero effect on plants that are close by or even touching the treated plant.

As long as I don't spread seeds by moving them around

I tried pulling some briars yesterday along the edge of my yard but it wasn't working very well, as they wanted to snap off just above the ground.

Get a garden fork and dig up the root wad, pretty impressive, and a sure fire way to kill it off.

Use crossbow!

Take a pic of what it is

Rubrus species aka brambles

Rubrus is a huge family present worldwide and includes blackberies and raspberries.

Roundup works well.

Some of those look like our raspberry plants. Our green brier looks a lot different than what I see in that photo.

Looks like black raspberries to me, I would encourage thier growth.

The waxy round stemmed vine to the right of the pic is Raspberry.

If these produce fruit it is not enough to speak of, not in this particular patch anyway.

Those are young canes would love to have em here