Collin County is Zone 8a

When making a plant selection it is important to know the zones where the plant will do best.

The USDA Hardiness Zone Map is a system for rating the cold-hardiness of plants, issued by the United States Department of Agriculture. This system divides the United States and Canada into eleven zones, based on average minimum temperatures in winter. The map was updated in 2012 to adjust for a trend towards warmer temperatures in various parts of the country. 

USDA Plant Hardiness Zone Map

According to the 2012 map, Collin County is in zone 8a. This means that generally, the coldest temperatures we experience range from 10-15°F. (The National Arbor Day Foundation hardiness zone map was also updated to reflect recent climate warming trends and has subsequently expanded Zone 8 to include all of North Central Texas.)

A word of warning about these maps: when choosing plants for your landscape, you should certainly pay attention to hardiness to understand how much heat and cold a plant can withstand, but take the zone information with a grain of salt. Such variables as sun, shade, wind and moisture can all affect how hardy a plant really is.