Tommy Tønsberg gardens in chilly Norway. The former editor-in-chief of Norsk Hagetidend, Norway’s largest gardening magazine, now writes about and grows plants. He also photographs and broadcasts about them. He lives on a property about 30 minutes north of Oslo with his partner Kenneth and three cats, Big Cat, Little Cat and Grey Cat. When not gardening, they propagate herbaceous perennials and some tender plants for their small nursery. I asked him about growing a garden in his Zone 7 climate and the jungle of houseplants inside his house. You…