What are these bugs on my baby trees and what should I do?

[BaleOfHay]

I bought three young cherry trees and am waiting to plant them. Their tips have become overun with little black bug and ants. What should I do?

Blackfly (aphids). The ants “farm” aphids for their sugary excretions. You could blast with a hose, or spray with a drop of washing up liquid diluted in a hand sprayer.

Or just gently rub off with finger and thumb. Remember they’re 90% water and mist if the rest is sugar - helps to diminish the ick factor

In future, try & encorage natural predators like ladybirds & their nymphs as they'll keen the aphid population down.
I've spent the last two years really focusing on making our garden a nature garden & this year is the first year our Cherry Tree (was planted 12 years ago) hasn't been infested with black aphids. There are loads of ladybirds & other insects in the garden helping to keep the pest population down.

I have a blackfly infestation on a philadelphus (among other things) and my flock of sparrows completely ignored it. However the day after I went and squished most of them (blackfly not sparrows), they came and perched on every bit of it. Presumably eating the remaining ones. Weird. I am trying to get the birds to do most of the pest control in my garden, the starlings have brought their fledglings for a leatherjacket feast for the past few days.

Blast them off with a hose or soapy water. When you've got all that you can find, run a few rings of vaseline round the stump of the tree and do so frequently to keep ants from trying to farm them.

Last year we had the same thing and I'll be honest I got a bit sick of putting vaseline on the trees and ended up just watching them interact. It was fascinating. But this year I'm back with a renewed energy to protect my apple tree and I'm not willing to let the bastards get me down.