Theo spent thirty-five years as a gardener on a National Trust for Scotland estate before retiring to a terrace in Edinburgh. The transition from walled gardens to a north-facing flat was, in his words, "educational."

He writes the long plant-care guides with the tone of a man who has actually killed the plant he's warning you about. He's particularly good on the old reliables — pothos, philodendron, sansevieria — and on the difference between what a plant tolerates and what it wants.