What sort of capacity?
I use "dumpy bags" for clearing up garden cuttings/waste - they're roughly 1 cubic yard.
Not really as far as I'm aware, except for the specimens cultivated deliberately.
We have stinging nettles, but they have different active compounds with different time frames. A nettle sting hurts straight away, causes a rash (oftentimes with small blisters), the effects last from a few minutes to a few days depending on how much you got stung.
(Sidenote, this week I cleared 5 dumpy bags of nettles and brambles from around my garden... I really should weed those areas more often.)
I am not sure of the capacity, but I would estimate maybe 50% larger than a typical yard waste bag, which is definitely bigger than a kitchen trash bag.
We have stinging nettles as well, I would take them over poison oak any day. I don’t find them terribly painful and for me they typically last a half hour or so. Easy stuff.
Poison oak, ivy, and sumac are closely related species, they might be limited to certain regions, I’m not sure. They all cause irritation with the same chemical, which I cannot remember the name of. Google-Fu could answer that question in a hurry.
The plants issue an oil that you get on you if you touch them, and the oil holds the irritant. It is subtle and you won’t realize it is on you if you don’t realize you brushed up against it. It could be on your clothes, and from that it gets spread to other parts of your body. If it is on your hands and you rub your eyes or pick your nose or take a pee, you’ve got real trouble. If your dog runs in it, you can get it from his fur. I think most animals are immune to it. Then it takes a day or two before you get symptoms, and it can take a week for all of it to materialize, so it seems like it just keeps getting worse. So if you don’t realize you were exposed, you might have no idea what is happening to you. Then it takes 3-4 weeks to finally go away, and the itch can last a week or two after the rash is visibly gone.
If you wash thoroughly very quickly after exposure, you MIGHT avoid it. But it chemically bonds to your skin and then it’s too late. The severity of reactions can vary from person-to-person, and some few lucky bastards are immune to it.
The oil does not break down, it needs to be washed away or you can get re-contaminated. Contaminated clothing has been put in storage, then taken out 30 years later, and caused reactions in people who handled it.
I wonder how the early European settlers handled it, before they knew what it was. Probably not washing much, not knowing what was causing the problem, wearing contaminated clothing, the delayed symptoms making it more difficult to identify the source, must have been miserable if they didn’t have Native Americans to teach them about it.