Most gardeners think they know the difference between annual and perennial plants. Annuals survive for just a season, whereas perennials come back stronger from the ground each year. Perennials are a fantastic investment for yards looking for a long-term investment, but many gardeners are attracted to annuals because they bring a quick pop of color for a great price. It turns out some of the frost-tender plants often sold as annuals in our climate can actually come back the following year under the right conditions.
Gardeners can be successful experimenting with perennials that are too tender for our climate if they select a warm location in the yard. Usually snow melts fastest in the part of the garden that faces south or west because that’s where the soil warms up the fastest. It’s also important to choose a spot that doesn’t sit in water during the wintertime, because this can promote rot. Tender plants will not survive in planters outside over the winter because the soil is exposed to much colder, but they are easy to bring inside.
Here are five common plants sold as annuals that actually survive the mildest winters in our climate. All of the plant in this list store the majority of their energy inside their roots. Like the classic perennials we know and love, these plants perform better and better with each passing year.
Calla lily
Calla lilies are a flower everyone has seen in a bouquet, but fewer have seen it as landscape plants. They absolutely deserve a spot in the garden though with their bold tropical foliage and flowers that last for 2 weeks or more! The small growing Calla lily varieties with colorful flowers are less cold tolerant than the larger, white flowered ones. The largest Calla varieties can grow up to 4 feet tall and survive temperatures down to 0°F.
These plants are often confused with Cannas, which also have bold foliage and beautiful flowers. Cannas have similar cold tolerance and will also come back from the ground with vigor if they are planted in a warm spot and the roots don't freeze.
Begonias
These plants have a reputation for being very tender annuals, but if the roots don’t freeze they will come back every single year. Even if the entire top of the plant seems dead, if the roots stay warm, they will easily outperform the new seedlings available at nurseries each spring. Begonia varieties like the “Wax Begonia” will recover from brief freezes down to 20F and are capable of going dormant for several months. They will only survive our mildest winters outside, but they are very easy to keep in a cool space like a garage and will patiently sleep until warm weather arrives.
For gardeners looking for a more uncommon plant, there are some "Hardy begonia species". One is the best is Begonia grandis, which can survive temperatures below 0°F.
Hedychium Ginger
This easy tropical plant is very rare to find growing in our area, but they are easy to take care of and can even survive the winter. Like edible gingers, Hedychium gingers have a large rhizome where most of their energy is stored. Although these are technically edible, they are grown for flowers, not food. The flowers are beautiful and incredibly fragrant, and the foliage goes in a symmetrical shape that adds a beautiful texture to the landscape.
Hedychium ginger will survive temperatures down to 10°F, or lower. It cannot survive if the roots freeze, and because they are such shallow plants, it’s a lot easier to just dig the root system up after the first freeze and keep it in a cool spot inside until next season. I've left a few of my ginger outside in the ground and have been surprised to see them return.
Tradescantia
This colorful ground cover is grown as a houseplant or a filler for planters during the summertime, but some varieties are cold tolerant. One of the more hardy is “Purple Heart” which has a deep purple color that no other perennial in our climate will provide. In mid and late summer, these plants produce adorable tiny flowers that are easy to fall in love with.
These plants are easy to start these plants by cuttings. Snip off a few vines in autumn and leave in a jar filled with water in the house. You’ll have new plants next spring if experimenting with them leaving them outside doesn’t work out.
Brugmansia
Brugmansia, also known as Angel Trumpets, is an incredible tropical tree that can be easily grow as a dieback perennial. These plants are grown for their large, fragrant trumpet flowers which appear in late summer and autumn. The plant is typically too tender to survive the winter outside but can surprise some gardeners during mild years. It’s very easy to cut back, dig up and store in a cool spot during the winter.
Just keep this plant away from curious children and pets. All parts of the plant are extremely poisonous if eaten.
True Annuals
It's true that many plants sold as annuals can actually live for many years, but there are plenty of plants that truly finish their entire life cycle in just a few months. The most famous annual is the common Sunflower which will not resprout after it finishes its bloom cycle. However, even these plants can (and often do!) make a surprise appearance the following year. Sunflower seeds survive our winters with ease and will patiently wait for spring to arrive. A few tropical plants, like Coleus and Vinca, will produce so many seeds that they'll sometimes pop up the following summer. What's especially fun about these plants is the offspring might look totally different from last year's parent plants.