Elsa, a few years ago I wiped out an aphids infestation literally overnight by sprinkling an order of ladybugs on them. I got them via a vendor on Amazon.
By morning, the ladybugs had flown, but there was not an aphid to be seen!
This spring, though, I had to cut out witches brooms in my bush honeysuckle. Those are caused by honeysuckle aphids. They tend to lay their eggs in the witches brooms. I hope I have ended that infestation by cutting out and bagging all those witches brooms, and then giving the entire bush a general shearing, and bagging those clippings as well. If the infestation recurs, my next step will be a new order of aphids from Amazon.
There is also an entirely different species of aphids that afflict irises. The summer they started to become a problem, I was able to get rid of them by spraying each iris fan on both sides with the Cornell recipe, containing water, neem oil, baking soda, and a drop of dish liquid to give wetability. I found the recipe online, and it really works. It also helps prevent mildew on peonies.
