Whether your phlox is winter-hardy really comes down to the specific variety you’ve got in your garden. Some types just can’t handle the chill, while others are total rockstars that can withstand temperatures as low as -20°F.
Annual Phlox: One Season Only
Annual phlox needs to be planted or sown fresh every single year. Even if you try to baby it with winter protection, it simply won’t survive the freezing months. That said, it’s totally worth the effort to replant annually—the color variety is absolutely stunning and adds a huge pop to any flower bed.
Perennial Phlox: Built for the Cold
Most perennial phlox varieties are quite hardy and can stick around for 10 years or more if you treat them right. While they are generally tough, it’s a good idea to take some winterizing steps if you live in a very cold climate or are facing a long deep freeze. You definitely need to step in if:
- Your phlox is growing in a pot or container.
- The plants are still very young.
One pro tip: Phlox actually needs a little water during the winter so it doesn’t dry out. Wait for a day when the ground isn’t frozen, and give it a light watering—just don’t overdo it!
Container Phlox Needs Extra Love
Plants in pots are more vulnerable because their roots don’t have the insulation of the deep ground, making them easy targets for frost. To keep them safe, move your pots onto a wooden board or a piece of Styrofoam to get them off the cold pavement. You should also wrap the pot itself to keep the root ball cozy. Great options for wrapping include:
- An old blanket
- Garden fleece (frost cloth)
- Bubble wrap
Adding a layer of mulch or evergreen brush on top of the soil also helps tremendously.
Protecting Your New Plants
A “baby” phlox isn’t nearly as hardy as a well-established one. If you’ve just recently finished planting or sowing, your little guys will need some extra help. A thick layer of mulch or some brush over the planting site is the best way to keep the frost from reaching those delicate new roots.
