Crocosmia (also known as Montbretia) are only somewhat hardy in our neck of the woods. When the temperatures really start to plummet, these beauties need more than just a little extra mulch—they often do best if you move them to a cozy winter home. Here’s the lowdown on how to keep your Crocosmia happy until spring.
–Crocosmia aren’t totally frost-proof
Since Crocosmia originally hail from the sunny landscapes of South Africa, they aren’t naturally built for our freezing winters. While they can usually handle a light frost or temperatures just below freezing, a long winter full of heavy snow and deep freezes can be a death sentence. To keep them coming back year after year, you’ll need to give them a little TLC when the cold hits.
–Your options for wintering
When the leaves start to turn, you’ve got a few choices for how to handle your Crocosmia. Generally, you can:
- Leave the corms (the bulb-like roots) right in the garden bed.
- Dig them up and move them to a protected spot.
- If they’re in pots, you should always bring them indoors for the winter.
***Wintering Crocosmia in the garden
If you live in a region with mild winters, your Crocosmia can stay put in the garden. Just make sure you give them a “winter coat.” Don’t cut back the withered leaves and stems yet—leave them attached to the corm throughout the winter. They act as a natural layer of insulation against the frost.
On top of that, you’ll want to spread a thick layer of mulch over the soil. Use a few inches of bark mulch, fallen leaves, or evergreen brush. This layer doesn’t just keep the frost out of the ground; it also helps maintain the right moisture balance and adds some natural nutrients back into the soil as it breaks down.
***Moving Crocosmia to winter quarters
If your winters are harsh, your best bet is to dig up the corms and bring them inside. This is also the way to go for any plants you have growing in containers. You’re looking for a spot that is cool and dry, but definitely frost-free. A dry basement, a garage, or a temperature-controlled greenhouse or sunroom works perfectly.
Before you tuck them away, go ahead and trim off all the top growth. Leaving the old foliage on actually drains energy that the corm needs for new growth in the spring. One pro tip: don’t let the root ball dry out completely over the winter. Give them a little water every now and then, but be careful not to overdo it—you definitely want to avoid soggy soil and standing water.
To make your life easier, I highly recommend using planting baskets or containers. If you plant the corms in these baskets before putting them in the ground, it’s a total game-changer. Not only does it protect them from hungry voles, but it also makes it incredibly easy to lift them out in the fall and pop them back in the ground once spring arrives!
