Geraniums are one of the most popular flowering plants used in summer containers and garden beds. Their bright colors and mounding habit make them a garden favorite, which leads many gardeners to wonder if they need to be replanted every spring. The answer depends entirely on which plant you are growing and where you live.
Understanding the Geranium Identity Crisis
The confusion stems from a long-standing misclassification between two distinct plant genera that share the common name “geranium.” The bright, showy plants most people buy for window boxes and patio pots belong to the genus Pelargonium. These are often called zonal, ivy, or scented geraniums, and are native to warm regions, primarily South Africa.
The other group, the Geranium genus, contains the plants known as “true geraniums” or cranesbills. While less common in annual displays, they are widely used in perennial garden borders. Both genera belong to the same plant family, Geraniaceae, but their drastically different winter hardiness determines their fate each year.
The Fate of Common Bedding Geraniums
The popular Pelargoniums are technically tender perennials that would live for multiple years in frost-free environments. In most temperate climates, however, they are treated as annuals because they cannot survive freezing temperatures. A single hard frost will kill the entire plant, including the roots and stems.
Garden centers sell these plants as annuals because they reliably provide color for one growing season before succumbing to the cold. In USDA Hardiness Zones 3 through 8, winter temperatures fall below the plant’s tolerance threshold, preventing the common bedding geranium from returning after winter.
How True Geraniums Return Annually
True geraniums, or cranesbills, are reliably cold-hardy herbaceous perennials that return year after year. These species (Geranium genus) thrive in USDA Hardiness Zones 4 through 8. They are characterized by deeply lobed foliage and smaller, saucer-shaped flowers, often in shades of blue, pink, or purple.
Hardy geraniums survive winter by dying back to the ground in the fall and entering dormancy. The root system remains alive beneath the soil, protected from the cold, storing energy until spring. They require minimal intervention, often just a spring cleanup of old foliage before new growth emerges.
Overwintering Tender Geraniums
If you wish to save your tender Pelargoniums rather than repurchasing them, there are several methods to keep them alive through the winter.
Taking Cuttings
The most common and space-efficient way is to take cuttings from the mother plant before the first hard frost. Take three to four-inch stem tips, remove the lower leaves, dip the cut end in rooting hormone, and place them in a sterile rooting medium like perlite or vermiculite.
Growing Indoors
Another option is to bring the entire plant indoors and treat it as a houseplant for the winter. Before bringing them inside, check the plants thoroughly for pests and consider washing the roots to prevent bringing unwanted insects into your home. The plants prefer cooler indoor temperatures, ideally between 65 to 70 degrees Fahrenheit during the day, and should be watered only when the soil surface is dry.
Storing Bare-Root
A third method, ideal for saving space, is to store the plants bare-root in a dormant state. Dig up the plant before the first frost, gently shake the soil from the roots, and trim the plant back significantly. Place the bare-root plants in a paper bag or hang them upside down in a cool, dry, and dark location (40 to 55 degrees Fahrenheit). Periodically misting the roots or soaking them for an hour once a month will prevent them from completely desiccating during their winter rest.