Just down the road from me, there's a bit of land (where I believe some cottages used to stand) which is now a 'nature park' but also serves as a sort of community garden, planted with apple, cherry and plum trees, and with a good growth of brambles.
I was very excited about the prospect of making plum jam, but someone picked the tree bare while I was off boating. Maybe next year. I'm toying with the idea of a plum tree in the garden - I have a lovely sunny wall - but ... wasps.
However, as I walked back through the park each day I picked a few blackberries, and put them in the freezer. Today, I finally got them out - because I've run down my stock of pre-prapared dinners, and wanted to take the opportunity to defrost the freezer. So, I had to preserve the blackberries the old-fashioned way:
I had 1 lb 11 oz (or 777g, if you prefer, which I don't. Love metric for measuring, but not for cooking) of blackberries. Having been frozen gave them a head start in the squishiness stakes, so they didn't need much stewing.