Before you fall in love with a new plant, it's worth checking your hardiness zone. These maps divide the country by typical winter lows, giving you a clear indicator of what will thrive and what might freeze. In the US, use the USDA Plant Hardiness Zone Map; in Canada, use the Natural Resources Canada Plant Hardiness map. Keep in mind that your garden's unique layout—like being tucked in a valley or surrounded by concrete—can make it slightly warmer or cooler than the official zone suggests.