What weeds, their seeds and roots will survive 6 month drowning?

[JustPotteringAbout]

I've set aside a couple of barrels for the drowning of perennial weeds. I chop the annuals/ ephemerals and leave them on the soil. I have one barrel for odd years fill, one for even years- as with my composters it helps rotation (though I have a finish bin for compost).
I leave the perennials on a black polystyrene box with a glass cover to dry them out.

Are there weed roots that will survive drowning for 6 months up to a year?
If any one the weeds have run to flower or seed (nettles, dandelion, Senecio spp) would the seeds be viable after their dunk?

[mothhawk]

Only aquatic ones, I think! Most weeds rot after a month or so completely under water, and that's the operative word here - completely. If you leave a bit of green sticking out, some perennials will just say thank you for watering so well The warmer it is, the faster they will rot, so stick your barrels in the sun, and do put a lid on, both for safety (animals, birds, small children) and because it will pong.....a lot!

[Two_Sheds]

Are there weed roots that will survive drowning for 6 months up to a year?

No, so long as you put a lid on the barrels, to block the light.
And seeds can't germinate if they've rotted

[JustPotteringAbout]

Thanks all. I painted the barrels with pound shop matt blank paint and the weeds are weighted down.
I left the lid off last year's batch in my haste to go to a talk this evening and there's a not unpleasant strong smell all the way up the street leading to my place again. I've smelt a lot worse.