However, there are exceptions, as a few newer rosemary cultivars have been bred to survive temperatures as low as USDA zone 6 with ample winter protection. Ask your local garden center about ‘Arp,’ ‘Athens Blue Spire,’ and ‘Madeline Hill.’ Read on to learn about protecting rosemary plants in winter.
How to Protect Rosemary in Winter
Here are some tips for winterizing rosemary plants: Plant rosemary in a sunny, sheltered location where the plant is protected from harsh winter winds. A warm spot near your house is your best bet. Prune the plant to about 3 inches (8 cm.) after the first frost, then bury the plant entirely with soil or compost. Pile 4 to 6 inches (10-15 cm.) of mulch such as pine needles, straw, finely chopped mulch, or chopped leaves over the plant. (Be sure to remove about half of the mulch in spring.) Unfortunately, there is no guarantee that your rosemary plant will survive a cold winter, even with protection. However, you can add a bit of extra protection by covering the plant with a frost blanket during cold snaps. Some gardeners surround rosemary plants with cinderblocks before adding mulch. The blocks provide extra insulation and also help hold the mulch in place.
