If you live in a cold climate, you might think you have to give up container gardening once the temperatures dip. However, there are lots of things you can do to garden in pots all year long.
Fall is a great time to experiment with texture and color in your container gardens. While mums and asters can be spectacular and classic in a fall container garden, there are lots of other choices that will last well beyond the first frost. Winter is tricky as many pots will break apart if they freeze, but there are some that will hold up to even the most frigid temps. Use this advice for keeping your garden growing all winter long.
Choose Cold-Hardy Perennials
While summer is a terrific time to go crazy with flowering annuals (those plants that only last one season in cold climates), fall is a wonderful season to try hardy perennials that will stand up to the cold in your container gardens. Have fun experimenting with color combinations you didn’t use in the summer. Purples and oranges, mixed with bright greens and deep reds can look stunning. Think texture by using grasses and interesting leaf textures like fuzzy lamb's ears.
For the best chances that your plants will survive a cold winter, choose perennials that are rated two zones colder than your area. Life in a pot is harsher and the roots aren't as protected as they are in the ground.
For fall containers, try some of these cold-hardy perennials:
Add Cool-Looking and Cold-Loving Annuals
While there are lots of annuals that instantly die at the hint of frost, there are plenty that will last well past the first frost. Some will even look fabulous and sculptural with a coating of snow. Try combining different heights and forms, or go simple and pot a single dramatic plant in a beautiful container.
Try some of these cold-loving annuals:
- Flowering cabbages
- Flowering kales
- Annual grasses
- Creeping wirevine
- New Zealand flax
Use Containers That Tolerate Cold
Make sure that your containers are made of a material that will withstand freezing and thawing. Ceramics, terra cottas, and thin plastics probably will not survive. Instead, try containers made of the following materials:
- Thick plastic
- Hollow logs
Throughout the winter, make sure that drainage holes are clear and use pot feet to elevate your containers. That way they won't freeze to the ground, which can break even the hardiest pot.
Plan for Frost
While you can’t buy your plants tiny down coats, you can help them survive the winter. In the fall, continue watering your container gardens. Stop fertilizing containers, particularly those that contain perennials, about six to eight weeks before the first frost date is predicted for your area. You don’t want to encourage new growth. It is too tender, won’t survive cold temperatures, and could even weaken or kill your plant. During a severe freeze, insulation blankets sold at most garden centers provide extra protection.
Understand What "Freezing" Means
According to the "Farmers' Almanac," here's what to expect:
- Light freeze (between 29 to 32 degrees Fahrenheit): Tender plants are killed, other vegetation is not dramatically affected.
- Moderate freeze (between 25 and 28 degrees Fahrenheit): Heavy damage to tender and semi-hardy plants can occur.
- Severe Freeze (below 25 degrees Fahrenheit): Only the hardy survive.
Replant Your Perennials as Needed
If you have a delicate container filled with perennials, dig the plants out and put them into a garden bed before the soil freezes. Or, depending on the plant, you may be able to turn it into a houseplant. Some plants that go dormant will survive in an unheated basement or shed. Do some research on your plant to see what the best chance for survival is.
Even if a plant is a hardy perennial, if it doesn't look great, or you just aren’t crazy about it, get rid of it. Add it to your compost pile and at least it will become food for some other plant down the line.