Ants on cherry tree but no aphids....
We have got a dwarf cherry tree and it is growing well, however, we have noticed ants are really interested in these red nodules on the stems of the leaves. There don't appear to be any aphids and we have treated it just in case but the ants still come back and carry on. Two questions from a complete novice are : 1) what are these red things on the stems and 2) what are the ants doing/ is it harming the tree?
Thank you for any help given as I've scoured the internet and asked as many people as i can but to no avail.