Posted: 20/04/2015 at 16:55
Hi Panda. We inherited a maturish Victoria plum tree which didn't fruit at all the first couple of years we were here (same with the mature Egremont Russet apple).
Two years ago we did major landscaping & the planting included 4 crab apple trees. Last year we had loads of blossom = loads of pollinators = super, bumper crop of really nice apples and bumper (well ok - 11 - ) crop of plums.
I have concluded that the poor cropping of plums is due to lack of pollination (Victoria is supposed to be self fertile) but I'm hoping it will get better year on year as we increase the pollinator friendly planting. Meantime I might try the old paintbrush trick myself...
Re aphids on the apple tree - encouraging birds is a good idea. I also get a bucket of soapy water and stiff brush and scrub off any of those patches of cotton wool the woolly aphids hide in. Doesn't get rid of them but helps to control them. I have been known to sprinkle ant powder round the base of my tree before now - didn't last long but made me feel better.