We all love the big splash of color that outdoor container plants deliver, but the cost of refreshing those pots once a year or more can get steep. It’s a two-step ritual: buy a horde of flowers at the garden center in spring, and then uproot and toss them in the compost in fall. Wouldn’t it be great if you could save some over the winter to replant for next year’s garden? It turns out many popular outdoor plants can handle life indoors and overwinter well with proper care, according to plant experts.
Which Plants Can Overwinter Indoors?
Not every type of garden plant will overwinter well indoors. “There are many plants produced for our summer’s use as ornamentals in containers or gardens. They fall into two groups,” says Byron Martin of Logee’s Plants for Home & Garden, a Connecticut nursery specializing in rare and tropical plants. “One group is made up of annuals, like zinnias or marigolds, and the rest are perennials, usually tropical perennials. So, when winter comes outside, they die off,” he says.
For example, most houseplants, from philodendrons to hoyas, are tropical perennials, Martin explains. If you’ve moved any houseplants like these outdoors for the summer, they need to come inside before the cold arrives or they’ll die. The same is true for many plants you may think of as a summer annual like begonias or geraniums.
You may have heard of overwintering geraniums (Pelargonium spp.)–perhaps your grandmother hung the dry root balls upside down in the basement–but you can also keep many other warm weather favorites such as begonias, abutilon, coleus, tropical hibiscus, impatiens, and sweet potato vines (Ipomea spp.) indoors.
“Theoretically anything can be grown as a perennial in the house as long as it’s given the conditions it needs to thrive,” says Martin.
Match the Plant to Your Conditions
Providing direct bright light, either on a sunny windowsill or via supplemental artificial light, is key, Martin says. The short days of winter reduce the natural light indoors significantly.
Though the plants may not continue to flower indoors, your goal is more to sustain their foliage and root system through the winter. They’ll be in a near-stasis of slow growth during the winter. For any plant you want to bring inside, research the air temperatures, humidity, and light the plant needs to survive.
Justin Hancock, horticulturist for Florida based houseplant experts Costa Farms, says most outdoor plants need “really bright light, like an unobstructed glass south- or west-facing patio door (east-facing may work if you live in the South).” If you don’t have the right natural light, he says, “A good set of LED shop lights can do wonders.”
When it comes to temperature and humidity, Hancock recommends “average household temperatures (65-85°F) and average relative humidity levels (40-60%).”
Selecting Plants to Overwinter
Hancock has successfully overwintered many types of tropical plants, even through long Midwestern winters. Here are a few that he liked to keep indoors until spring:
Some plants are easier to overwinter than others. For example, coleus, geraniums, succulents, abutilon, sweet potato vine, and begonias are among the easiest. More challenging plants such as jasmine, tropical hibiscus, and mandevilla require lots of light and consistent warmth that the typical home may not provide.
Ways to Overwinter Plants Indoors
There are several methods of overwintering plants inside, from semi-active growing in a warm, well-lit spot, to dormancy in a cool, dark space. For many plants, it’s easier to do the latter method because you’re not asking the plant to maintain vegetation in your low-humidity, low-light house.
Some plants go fully dormant for dry storage with soil removed, like dahlia tubers. Others can be kept dormant in pots once the leaves are cut to the base, like banana plants, cannas, and Colocasia, says Martin.
Hancock keeps prized plants that he knows he wants to overwinter in containers, even if that means planting the pots in soil. That way he can just dig up the whole pot in fall, saving the plant from the root stress of transplanting.
If you want to keep the plant in a semi-active state, don’t be surprised if the plant reacts to its new environment by dropping leaves soon after it comes indoors. It may also grow leggy and lanky, reaching for the light by spring. One thing that can help is to take stem cuttings close to spring. Impatiens, geranium, coleus, and begonias root easily in water, damp perlite, or seed starting mix, says Hancock. With fresh new roots, your cuttings should be ready to grow well once moved outdoors again.
If you fall in love with these plants inside, Hancock says coleus, bougainvillea, abutilon, and rex begonias are some popular summer annuals that can become full-time houseplants.
Steps for Overwintering Plants Indoors
Once you’ve selected the plants you want to overwinter in your home, follow these steps to keep them going until the next spring.
- Bring outdoor plants indoors. Make the move indoors before temperatures fall below 40°F.
- Clean off plants. Deal with any insects or disease issues if necessary. Remove dead leaves and prune as desired.
- Pick a sunny spot. Place your plants in your sunniest space indoors. In order of light strength from brightest to lowest, choose south, west, or east-facing windows.
- Water sparingly. After watering the plant well upon coming indoors, keep it only lightly watered through the winter, allowing the soil to dry out between waterings. Unless growing quickly, most plants won’t need fertilizer. As days lengthen and brighten toward spring, growth should speed up, at which point you can water more often and lightly fertilize.
- Harden off before going outdoors again. Wait until temperatures have warmed to at least 50°F, then begin hardening your plant off gradually. To do so, take the plant out to a shady location in the afternoon when temperatures are warmest, and bring inside after a few hours. Keep moving the plant in and out for about a week, slowly increasing its sun exposure if it’s a plant that needs direct sun. After hardening off, the plant can remain outdoors wherever you’d like it.