I am always aware that not all gardeners are lucky enough to have a garden but have to suffice with a terrace or patio or even just a wall to hang pots from as is found in Southern Spain where the famous patios of potted flowering plants are part of a tourist route. Here Geraniums really do well and I find that literally any little cutting just stuck in a pot will take root. Unfortunately, we suffer that little grey butterfly that lays its eggs and the hatching larvae burrows into the stems of the Geranium. You are aware of this when the flower stem rots back and there are little black holes near the leaf joints. Cutting the stems back to below the black holes can frequently save the plant but it’s best to catch the butterfly if you can before it lays its eggs. There is a pesticide available for just this plague available from the garden shops and Co-op. There are those who believe in the vinegar mixture but it’s up to each one of us how we protect our plants from plagues.