While our perennial plants can withstand the winter without a problem, our annuals aren't quite as resilient when it comes to braving the cold and snow. In fact, in our cold climate in North Dakota, they aren't resilient at all-they die off after the first frost or two. Many gardeners are used to parting ways with their annuals in the fall and prepared to start fresh in the spring. But the beauty of annuals doesn't have to be so short-lived! If you've got the space, try overwintering yours indoors this year so they'll still be kicking around in the spring!
Just because you bring annuals indoors, doesn't mean they're going to survive. Plants that adapt well to overwintering are ones that might actually be considered tender perennials-perennials that are grown as annuals in cold climates. Here in North Dakota, we grow a lot of plants that could actually survive the winter in warmer climates, but that just can't handle our Northern winters.
There are a few different methods for overwintering plants. Here's how you can help your annuals make it through the winter:
If you're familiar with keeping plants over the winter at all, you might already know that many of them are able to masquerade as houseplants for the cold months. Heliotropes, impatiens, jasmine, hibiscus, and hostas are just a few of the lovely plants you can keep cozy with you indoors this winter.
The most important thing is to get them out of the ground before they can be damaged by the first frost. If they're planted in your garden, dig them up and place them in a container with fresh potting soil-like a little winter vacation home.
When you bring your containers inside, try to imitate their ideal growing conditions as well as you can-unless they'd rather hibernate. Many plants will enjoy a warm home near a sunny window to ensure they receive plenty of light. Water your plants as needed, but keep in mind that they won't need quite as much since they aren't doing much growing at this time of year.
Sometimes gardeners choose to overwinter plants that could survive the winter outdoors, but that would rather not. While most perennials will pop back up in the spring, some might be lost if they aren't covered and insulated well enough, or if they don't conserve enough water during the fall.
For example, overwintering hostas indoors and overwintering hydrangeas indoors is a good idea if you've had a particularly dry fall. If these are one of your garden favorites and you don't want to take any chances, you can let them live out their dormant state in a cool, dark place inside, like a garage or shed. Other plants, like brugmansia and dwarf canna, would prefer to hibernate in a dormant state as well.
Not all plants are well-suited to the houseplant lifestyle. Instead of trying to save the "mother" plant, sometimes it's easier to simply take a plant cutting that can be re-planted to your spring garden to grow a brand new, baby plant!
Herbaceous annuals with soft stems, like coleus and geraniums, might be easier to re-grow through cuttings than to keep as houseplants. To do this, take 3 to 5-inch cuttings of non-flowering plant shoots during mid- to late-summer. Be sure to choose young, healthy stems rather than older, tough or woody stems that might not be as successful. If there are any flowers or buds, make sure to pinch them off, as well as any leaves that remain on the lower portion of the cutting. Stick the cutting in water and wait for the roots to develop, at which point you can plant it in a small container and place it on the windowsill. Keep the soil moist and fertilize your cutting regularly, and it'll be more than happy to be re-planted in warm soils when spring arrives!
Similar to taking cuttings, you can also dig up tender bulbs and tubers in the fall and store them to be planted back in the ground come spring. This is how you can overwinter begonias indoors, as well as dahlias, canna lilies, calla lilies, elephant ears, and sweet potato vines. You'll know it's time to dig them up when the existing plant's foliage begins to yellow. Take care not to damage the bulb as you remove it from the ground, gently shaking off any soil. Rinse them to clean off any remaining dirt, and place the bulbs in a shaded, dry place to dry out. Most bulbs can then be stored in a dark, dry place or replanted in a pot and kept as a houseplant for the winter.
Saving your annuals from certain demise not only makes your spring a lot more colorful, but it makes your winter a little more lively, too! Surrounding yourself with hibernating plants is a great dead-of-winter reminder that you'll see the grass again, even when it seems as though the snow will never melt in Bismarck. Overwinter your favorite annuals this year to beautify your winter home and enhance your spring garden!