How to Overwinter Geraniums in Montana
Every fall someone tells us they hate to “throw away” their geraniums when frost comes. Good news: you don’t have to. Geraniums are one of the easiest plants to carry over the winter, and a plant you keep going gets bigger and better each year. Here are the three ways we do it — pick the one that fits your space.
First, beat the frost
Whatever method you choose, bring your geraniums in before the first hard frost — here in the valley that can come in September. A light frost can nip them; a hard freeze will end them. So keep an eye on the forecast and act while the plants are still healthy.
Method 1: Pot them up as houseplants
The simplest approach. Dig or lift your geraniums, pot them in fresh potting soil, and bring them indoors to your sunniest window — a south-facing one is ideal. Cut the plant back by about a third to reduce stress and legginess. Water only when the top inch of soil is dry; indoors they need far less than they did outside, and soggy soil is the main way people lose them. Don’t expect much bloom in the dark months — you’re keeping the plant alive, not pushing growth. In spring it’ll wake up and take off.
Method 2: Take cuttings
If you don’t have room for big pots, take cuttings instead. Snip 4-inch tips from healthy stems, strip the lower leaves, and let the cut end callus for a few hours. Pot them in a light, well-draining mix, keep them in bright indirect light, and they’ll root in a few weeks. One parent plant can give you several new ones — a nice way to multiply a variety you love or share it with a neighbor.
Method 3: Dormant (bare-root) storage
The old-timers’ trick, and it works. Dig up the whole plant, shake off the soil, and store it bare-root in a paper bag or hung upside down in a cool, dark spot that stays around 45–50°F — an unheated basement or root cellar is perfect. Once a month, soak the roots in water for an hour to keep them from shriveling completely. The plant will look dead all winter; it isn’t. In spring, cut back the dried tops, pot it up, water it, and watch it come back. This method saves the most space and the most plants if you have the right cool, dark place.
Come spring
However you carried them over, harden your geraniums off gradually before they go back outside, and don’t rush them past our late-May frost. A little effort in fall means a head start — and free plants — in spring.
Want to add to your collection, or not sure which method suits your variety? Come see our geraniums and we’ll talk you through it.