Not all varieties of the popular Coreopsis (also known as Tickseed) are fully hardy enough to stay outside all year long. Some types need a little extra TLC to make it through the frost without damage. Here’s how to keep your Coreopsis happy and healthy until spring.
Not All Varieties Are Winter-Hardy
While some Coreopsis varieties are tough as nails and can handle freezing temperatures on their own, not all of them share that “winter warrior” DNA. Some subspecies simply won’t survive a harsh winter in the ground and need to be overwintered properly to ensure they come back next year.
Overwintering Hardy Varieties in the Garden
Even the hardy types have their limits when the thermometer really drops. While they can generally stay in your garden beds, it’s a good idea to give them a little extra protection just in case.
Mulch is Your Best Friend
Cover your garden Coreopsis with a protective layer of mulch. You can use whatever you have on hand, such as:
- Pine or spruce needles,
- Bark mulch,
- Fallen leaves or grass clippings,
- Or similar natural organic matter.
A good mulch layer doesn’t just protect the roots from freezing soil; it also helps the ground retain much-needed moisture.
Using the Plant’s Own Foliage
You can certainly prune your Coreopsis before winter sets in. However, another great trick is to leave the withered foliage on the plant until spring. This dead growth acts as a natural insulation blanket against the cold.
Overwintering in Pots
If you’re growing Coreopsis in containers, or if you have a non-hardy variety, it’s time to move them to a “winter home.” Look for a spot that is bright and cool, but strictly frost-free. Dry, bright basements, garages, or unheated sunrooms are perfect. Avoid bringing them into your heated living areas; the warmth can trick the plant into sprouting too early, which weakens it.
If you have a hardy variety in a pot and want to leave it outside, make sure to wrap the pot in burlap or garden fleece. Also, lift the pot off the cold ground by placing it on a piece of Styrofoam or wood to provide some insulation.
Winter Maintenance Tips
Don’t “set it and forget it!” Even during their winter nap, Coreopsis plants need a little attention. Whether they are in the ground or in a winter shelter, the soil should never dry out completely. Give them a drink of water every now and then. Persistent drought during the winter can be just as damaging to the roots as the freezing cold!
