Johnny Jump-ups (Horned Violets) are a total garden favorite for spring, and they’re great because they keep those cute little blooms coming all summer and even into the fall. But what happens when the thermometer starts dipping toward zero and that first frost hits?
Are Johnny Jump-ups Frost-Hardy?
These little guys are tougher than they look! Since they’re originally from the Pyrenees mountains, they’re used to a rugged climate. Generally, they’re frost-safe down to about 5°F (-15°C), though they’ll need a little help if it gets even colder than that. They actually have a secret weapon: glycerin in their cells, which acts like a natural antifreeze to protect them from freezing. Even so, sometimes they don’t make it through the winter. Here’s why that usually happens:
- “Black Frost” (Freeze-Drying): When it’s freezing cold but there’s no snow cover, the root ball can freeze solid. The plant can’t “drink” any water and ends up drying out.
- Too Much Water: Constant rain or poor drainage leads to soggy soil, which rots the roots.
- Old Age: Sometimes the plant is just at the end of its life cycle and doesn’t have the energy left to survive the winter.
How to Overwinter Your Violets
If you live somewhere with brutal winters, frequent dry freezes, or tons of winter rain, your Johnny Jump-ups will need a little TLC. While plants in the ground are pretty hardy, those in pots or window boxes are much more vulnerable and always need some extra protection.
Most modern hybrids can handle temperatures down to 5°F, while some heirloom varieties are hardy to about 23°F. For plants in your garden beds, you’ll want to cut them back in late October and cover them up with:
- Garden fleece or frost blankets
- Brushwood or evergreen boughs
- Dried leaves
- Moss
- Bark mulch
During the winter, you can skip the fertilizer and usually the water, too. The only exception is during a dry freeze—if the soil is parched, give them a little water once the ground thaws out. Interestingly, a snowy winter is actually great for them! Snow acts as a perfect insulator and provides steady moisture, so don’t bother shoveling the snow off your flower beds. You can pull back the winter mulch as early as late February or as soon as the snow melts.
Overwintering Violets in Pots
If you have the space, you can move your potted violets into a frost-free garage or basement. If they’re staying outside, you’ve got to protect the containers so the roots don’t freeze solid. Move your pots and window boxes to a sheltered spot and wrap them in burlap, frost fleece, or even bubble wrap. It’s also a smart move to lift them off the cold ground by placing them on a wooden pallet or a piece of Styrofoam. Finally, cover the soil surface with some evergreen branches or leaves.
Pro Tip: If you’re growing these in pots, always make sure you have a good drainage layer of gravel or broken pottery at the bottom. Preventing “wet feet” is the number one way to keep your violets happy during a rainy winter!
