I don't have any problems with aphids at all. Years ago I used to spray them with soft soap. Now I just encourage ladybirds into my garden by not cutting back the herbaceous plants in the autumn and by refusing to use any sprays at all. I leave the leaves and stems in situ and don't cut back the old stems or clear the soil until about late April or May. The ladybirds settle down nicely in the old leaves and stems etc, keep warm over winter and then breed like mad from the spring. Their young eat the aphids.The garden looks stunning in the frosts of winter. It's a bit untidy in the spring for a little while - but it's worth it!