I am new to gardening and recenty planted two campanula bernice under a red robin standard tree in our back garden which is east west facing. I planted them on the sunnier side of the gaden. I’ve been giving them a liquid feed once a week but they don’t look very happy! The flowers seem to get sticky and die off before they open? Any ideas what could be the problem?
It does not want or like liquid feeding every week. In general, the vast majority of garden plants can get enough nutrients from ordinary soil, only vegetables, roses and fruit trees need feeding.
So water once a week until you see signs of active new growth and leave it at that. The photinia might grow out over it eventually and the campanula will need to be moved.