We are, as a nation, partial to gardens. The garden visitors (as opposed to the house visitors) are those I remember best from the years when my parents used to open their Jacobean home to any and all, every weekend – and hope for custom. Bad weather often kept house tourers away; downpours never defeated the gardening enthusiasts. Peering down from the nursery window on gusty Sunday afternoons, I watched our visitors undergo their transformation from checked shirts and floral skirts into an army of intrepid marching mushrooms in beige and black: they got extremely wet, but they never quit.

Catherine Horwood, in this ambitious study, suggests that gardening runs in families. Alas, but no. My grandmother, so far as I know, had nothing whatsoever to do with the gorgeous gardens at Chirk Castle (of which she was, during her married life, the chatelaine). Instead, she sensibly recruited