When you look at those colorful plant tags tucked into the pots at the nursery, there’s usually a tempting picture on the front and, on the back, some text. Apart from a short description and some advice on the conditions the plant prefers, you’ll find something that may seem little puzzling: 'Zone 6' or 'Zone 7', perhaps only 'Z6' or 'Z9'.
When you see 'Zone 6' or 'Z6', this refers to a hardiness zone, and is a guide to the winter temperatures that the plant will survive. But what does it mean?
