My ground roses that are exposed to very hot sunny conditions and are near my neighbors trees are not flourishing. More water or fertilizer?
The lack of good sunshine is likely the problem. It could be that the trees are providing too much shade on those roses and thus their performance is stunted. I would have a conversation with my neighbor and see if they or I could limb up/prune the trees just a bit to allow more sunshine through to the roses. If that works out, the problem could be cured. Otherwise there may be little hope of having their performance match the others. Keep feeding and watering as you are as it sounds like the other roses are doing fine. Those in the shade will either adapt in time and have the best performance they can for their growing conditions or stay in a stunted state that may well lead to disease taking hold and their demise.