Overwintering geraniums – how to protect your plants and help them survive the cold winter months

Geraniums are among the most popular summer plants in the UK, putting out beautiful, long-lasting blooms. But overwintering geraniums means you'll be able to enjoy the flowers next year, too.

Learning how to grow geraniums is easy, but if you're wondering what to do with geraniums after flowering, you don't need to turn to the compost bin just yet – in fact, these plants can survive the winter months with the right overwintering techniques.

'Geraniums aren’t fans of cold weather, but the great thing is they’re pretty easy to care for during winter with just a bit of planning,' agrees David Denyer, expert florist and gardener at Eflorist.

We've put together a guide to overwintering geraniums to help you out.

David Denyer

David Denyer is a six-time Chelsea Gold Medalist and two-time Florist of the Year at Eflorist. With over 35 years of floristry experience, David has captivated global audiences with his artistic talent, creativity, and passion. He has become a well-celebrated and influential figure in the industry, solidifying his reputation with appearances on the renowned television show Gardeners’ World.

Overwintering geraniums: a how-to guide

Geraniums hail from warmer, drier climates, so if you're wondering how to overwinter geraniums, you'll need to keep them dry and frost-free during the colder months.

There are several different overwintering methods you can use...

1. Bring them indoors as houseplants

Believe it or not, you can bring your geraniums inside and treat them like houseplants during the winter. Just make sure you bring them indoors around six weeks before the first frost.

'Geraniums can make fantastic indoor plants during the colder months,' says David. 'They’re low-maintenance, cheerful, and can really brighten up your space when the outdoor garden is dormant.'

First, you'll need to choose a spot with the right conditions. 'When bringing them inside, lighting is key,' David says. 'Geraniums thrive on light, so try to place them in a sunny window where they’ll get at least six hours of sunlight a day. If you don’t have a bright enough spot, don’t worry – grow lights work just as well.'

You can buy grow lights at garden centres and various online suppliers, like the wolezek Grow Lights from Amazon.

Even though your geraniums will thrive best in the sun, they do prefer cooler temperatures – around 10-18°C, according to David. Keeping the plants cool will prevent them from becoming leggy.

If your plant does become leggy, a light prune will do the trick. 'If they start stretching out and becoming leggy, just pinch back the stems,' says David. 'This will encourage a fuller, bushier plant that will look great all winter long.

'As for watering, it’s pretty straightforward. Let the top inch of soil dry out before watering. Geraniums are fairly drought-tolerant, so it’s always better to underwater than to overdo it.'

If your geraniums are already in pots, you can keep them as is: let the pots go fairly dry (but without drying out completely) and bring them indoors for overwintering.

If your geraniums are planted in your garden borders, however, Chris Bonnett, founder of GardeningExpress.co.uk, says you can absolutely dig them out and pot them up with fresh soil. 'You’ll want to prune the plants by half to encourage growth next spring,' he adds.

2. Take cuttings

Fun fact: learning how to take geranium cuttings is absolutely a form of overwintering geraniums. Who knew, eh?

By raising cuttings into new plants, you can bring copies of your beloved geraniums into next year. Whether you choose to overwinter your remaining plants or dispose of them is up to you.

'You should aim to do this before the first frosts occur, as geraniums do not usually survive winters in the UK,' says Graham Smith MCIHort, gardening expert at LBS Horticulture.

3. Bare root storage

Only suitable for overwintering geraniums with thick, woody stems, this method demands that you lift plants from the ground before the first frost and store them as bare roots.

'Shake off any excess soil and place them somewhere cool and dark, like a basement or garage, where the temperature stays around 7-10°C,' advises David from Eflorist. 'Hang them upside down or store the roots in paper bags if you have some on hand.'

Check on the roots every few weeks to make sure they aren't dry. If they do feel dry, lightly mist them with water.

When spring arrives, inspect the roots for new growth and discard those without. Soak the roots in water for a few hours, then pot them up and cut back all stems to around 10cm. Water them sparingly and keep them in a greenhouse until they're ready to be hardened off and planted outdoors.

4. Cool storage

Another riskier method of overwintering geraniums asks that you cut the plant back by one-third to one-half, wrap the pot in bubble wrap, water it deeply, and stash it in an unheated greenhouse or shed.

Some people prefer to cover their plant babies with a garden fleece like this one from Amazon, just as an extra precaution.

If you choose to follow this method, keep checking the plant for signs of disease, keep the temperature at around 2 to 4°C, and water sparingly when they show signs of drying out.

FAQs

Can I overwinter geraniums in the garage?

A garage is a popular overwintering location, but you'll need to make sure it doesn't get too cold if you'll be keeping your geraniums there. Avoid overwintering bare roots or plants in the garage if gets frosty in there during the winter, as these conditions will kill the plants. If you're not sure, consider wrapping the pots in horticultural fleece or bubble wrap for extra protection.

How do I save my geraniums for next year?

If you don't have lots of geraniums, the easiest way to keep them alive over winter is to make like the Swedish and bring them indoors as house plants. Find them a bright spot (a sunny windowsill is ideal), water them sparingly, and get ready to plant them out next spring.

Just be sure to harden them off first, either by using a cold frame or, alternatively, wrapping them in fleece and popping them in a sheltered spot.

Personally, we're most fond of the first method for overwintering geraniums, as it means we get to enjoy them and coddle them for longer. How about you?