what to spray for wild blackberries?

[greybeard]

If spot spraying I would probably use my nuclear mix. Of 1to 100 tordon22 mixed with 1to 50 remedy. I haven't found much it won't kill.
I think for broadcast I would probably lean toward surmount.
Pasturegaurd and chapperal are pricey options if you don't have a applicator licence

I like Tordon too, but can't use much of it. Got too much water I have to be careful about.
Tordon is certain death to tallow trees tho.

Does everyone call those dewberries, or is that a local thing here?

Rafter, Over here in lowly San Jac county, dewberries grow down low, and blackberries make bushes big & tall as a tractor..or bigger.

Something I'll never forget.....
Decades ago, I'd been stationed in Tenn for a year, then got sent to Guantanmo for 24 months and came back on 30 day leave to find one of the 40 acres parts of my dad's place completely grown up in blackberry higher than I could see over. I decided to mow while I was home, & started his nearly new Leyland and hooked a 5' Modern bush hog behind it. "I got lots of them mowers, but that's the best one--don't tear it up" is all he said...

I'm easing thru that stuff, standing up on the floor plates so I could kinda see, watching for a cross fence I knew we built in the late mid 60s, (knew it was there because I'd got hit by lightening building on it) when the whole front end dropped off in a big ditch about 15' across and 4-5' deep. Came close to chunking me over the hood. Killed the engine, crawled off the back and over the mower and went to find my Dad.
"You run out of diesel already?"

No, I'm stuck"
Well, get in the truck, I'll pull ya out".

me:
We're gona need more than your truck..I drove off into some kinda big axed ditch that didn't used to be there and I can't back out of it or even start it--it's under water up to the radiator fan"

him:
Oh, &^%$* son, I was gonna tell ya about that and forgot to. I had it dug 2 summers ago when I had an excavator in here doing some dam work, so the horses would have water all the way to the front. There's 2 more further over East too".
:bang: :bang:
Every time I think about that, I think how lucky I was I drove straight into it and not from the side with both right side tires dropping off. Woulda turned over sideways and drowned me right there with my last thoughts on Earth being "What the hell did I just drive into? --that was never here before..."