The Pine rust is a real concern. When I was a kid we had half dead pines around our garden. Turns out they had contracted something from are black currants.
I had a good
feed of black currants yesterday, from an area that gets slightly more sun than the one in the video.
A single plant becomes a clump, becomes a patch. It can be sped up with some transplanting. Then you do nothing. You don't prune them, you don't
water them, you don't worry about them. Just pick.