Crotons

Crotons are prized for their eye-catching leaves that sport splotches and splashes of red, yellow, and orange. These plants are native to the tropical regions of Asia, and they don’t fare well when temperatures dip below 50°F. In chilly nights, cover your crotons with a frost blanket. Before cold weather sets in for good, bring them indoors. Crotons also make exceptional houseplants.

Elephant Ears

Elephant ears are only winter-hardy in Zones 9 and up, and they grow best in warm weather. Once temperatures fall below 50°F, elephant ears should be protected with frost blankets or covered with a cardboard box, a plastic jug, or another type of insulation that wards against frost.

Even with this extra protection, elephant ears will only last for so long in cold weather, but you can dig up and overwinter the tubers indoors to replant them next year.

Petunias

Although wave petunias and a few other cultivars survive light frosts, most petunias aren’t frost hardy. In cold weather, they wither away or turn to mush, but insulating them can keep them in bloom a little longer.

If you’re growing petunias in small pots or hanging baskets, simply move your plants indoors when frost is in the forecast and put them back outside when the weather warms again.

Ornamental Peppers

Peppers are native to areas of Central and South America where temperatures stay relatively mild year-round. Although they may survive a light frost, they struggle when temperatures fall below 55°F and will die back entirely after a hard freeze. Ornamental peppers have the same temperature sensitivities.

When it gets too cold for the plant outside, simply bring it into your home and give it a spot near a sunny window. As a houseplant, ornamental peppers add a welcome burst of color during the dark winter months.

Before bringing any plant from outside into your home, check it over for pests. Wash the foliage, both top and undersides of the leaves, thoroughly with water, and let the foliage dry completely before bringing it indoors.

Begonias

The tender stems of begonias store a lot of water, which helps them naturally resist dry soil. However, those water-filled stems also make begonias more susceptible to frost damage, as these plants freeze right through in cold weather.

Many gardeners treat outdoor begonias as annuals and toss them in the compost pile at the end of the season, but some varieties, like rex begonias and angel wing begonias, make excellent houseplants if you overwinter them indoors.

Million Bells

Million bells, also known as calibrachoa, grow best when temperatures linger between 55 and 65°F, while colder weather causes damage or death to these plants. As with other frost-sensitive flowers, million bells benefit from cold weather protection with a box or plastic jug before frost hits your area.

If your plants sustain minor cold damage despite this protection, trim away the worst-hit stems and leaves, and your plants may just flower a little longer.

Coleus

A top pick for window boxes and porch planters, coleus are some of the most popular foliage plants. Despite their fleshy leaves, these plants are native to tropical regions of Southeast Asia and Australia aren’t built to withstand the weather in colder regions.

If you want to try overwintering coleus indoors as houseplants, place them near a humidifier or pebble tray to meet their needs for high humidity.

Annual Geraniums

Unlike hardy geraniums, which are perennials in most climates, the common annual geranium won’t survive a hard frost or freeze. These plants will usually stop growing when temperatures fall below 50°F, and temperatures lower than that cause stress and more serious damage. 

To prolong the plant's lifespan a little, cover it with a sheet during cold nights. Once daytime temperatures get too cold, most gardeners discard the plant.

Impatiens

Like begonias, impatiens have fleshy stems that make them more vulnerable to freezing. Most impatiens grow best when nighttime temperatures are above 60°F, but some hardy varieties continue to grow even when the weather gets a little cooler. Frost, however, will cause major damage to these plants, and they definitely won’t survive a freeze.

To overwinter potted impatiens indoors, bring them inside when nighttime temperatures drop below 60°F.

Sweet Potato Vine

Whether you grow them for their edible tubers or simply as ornamental vines in container gardens, sweet potatoes are heat-loving plants that won’t tolerate cold weather one bit. Temperatures below 50°F damage the plants, and hard freezes will kill them.

However, like crotons, begonias, and many other container plants, sweet potato vines can be grown as houseplants if you want them to last through winter.

Dracaena

In fall container gardens, dracaenas are often used as thriller or filler plants whose spiked, colorful leaves add texture to arrangements. These tropical plants aren’t hardy and suffer when temperatures drop below 60°F, so they should be moved indoors as fall weather sets in. To keep dracaena healthy as a houseplant, run a humidifier to ensure average or above-average humidity.

Basil

Some gardeners grow basil in containers as an edible, or use ornamental basil varieties to add color and texture to container gardens. Basil is a cold-sensitive plant whose leaves turn black when temperatures drop below 50°F. When exposed to frost, plants die. If you’re growing basil for edible use, be sure to harvest the remainder of your plants while the weather is still warm.

Once it's too cold outside, move your basil indoors and grow it year-round on a sunny windowsill.