Seamus O’Brien, head gardener of Kilmacurragh surrounded by the flowers of the tree rhododendron, R.arboreum ssp. cinnamomeum, which is in full bloom in the gardens at the moment. Photograph: Richard Johnson

An awfully long time – roughly 140 years – has passed since the famous Broad Walk of Kilmacurragh in Co Wicklow was first laid out by siblings (...)