Leaves curling on black and on white currants
I hope this is the right forum for this. I have planted 3 currant bushes this spring within 6 feet of each other. A red, a black and a white. The red is doing OK (i think) but the black and the white ones are showing some leaf curling (and yellowing) as seen in the picture below. I have checked for aphids/mites but can't see anything.
Any ideas what could be causing this? Do I need to worry/do something?