black berries

Cut back all the dead growth off the black berries today. I was wondering about what to give them a feed. With and other fruit bushes

Would potash be ok for other fruit bushes raspberry gooseberry red currant

no help to you i'm afraid but i have a massive blackberry bush that grows over my fence from the industrial estate behind my garden. obviously i don't feed them and god knows what substance they grow on. they gave a massive crop last year, which was a bonus as it's a new house to us.

not wanting to hi jack the thread but is it worth pruning / cutting back any of the old growth?

if so how would i go about it and what do i cut and what not to cut?

i can only get to the parts of the jungle that are 6 or 7 foot tall (at the top of the fence), and have no access to the growth that is the other side of the fence.