If you want to know how to overwinter your favourite tender geraniums (more correctly called pelargoniums) to enjoy the following year, we’ve got you covered. Pelargoniums don’t have a dormant period, so the easiest way to keep them going through the winter is to dig them up and keep them as indoor houseplants on sunny windowsills. Here’s our how-to guide and video to tell you everything you need to know about overwintering pelargoniums.
How do I choose which geraniums to overwinter?
First, consider whether the variety you have is a favourite and worth spending time and trouble on. If it’s not, leave it in the garden to fend for itself and buy a different variety next year!
Second, think about whether you have enough space for all your tender geranium plants. Few of us have enough frost-free room to keep every plant, especially if they’ve grown very large. You can either:
- Cut back the plants you have in pots, so that they spend the winter re-growing and bushing out. This works if you have plenty of frost-free space.
- Take pelargonium cuttings and leave the old plants to get on as best they can, or throw them away. Cuttings are much smaller than full sized plants, and make better use of limited storage space.
Top tips for overwintering your geranium plants – video guide
Watch our video and follow these top tips to successfully overwinter your favourite pelargoniums:
- Before bringing your geranium plants inside for the winter make sure you examine them well first. Clean off any dead leaves or dying flowers and look for signs of pests and diseases like rust. This only affects the zonal pelargoniums but it’s getting more common. It first came into the country in 1968 and particularly thrives during a damp summer or autumn. Luckily, it doesn’t seem to infect the plants very rapidly and is easily treatable, so simply removing the affected leaves is a good control. You could also try spraying with a fungicide called Dithane945.
- Light is still important in the winter so place your overwintering plants somewhere bright and sunny. If your plants are over three feet away from the window they get 50% less light!
- Keep the roots moist because your plants continue to grow over winter. Geraniums will often survive a drought, but will not thrive. People growing show plants are careful to ensure their plants’ roots are moist but never wet during the winter.
- Ventilate as often as possible to keep the atmosphere around your plants dry. If you don’t allow the air to move, your plants will end up a mouldy, rotting heap. Automatic electric fan heaters are best as they move the air around whilst also increasing air temperature.
- Geraniums only need to be kept frost free, so are very economical to overwinter in the greenhouse. However, we do recommend using a heater to ensure temperatures stay above freezing. If your heater has a thermostat, set it at 5°C or 41°F. If the stems get frosted then the plant will die and not recover! Porches, sunrooms or conservatories are also excellent places to keep your tender pelargoniums through the winter.
We hope we’ve given you plenty of ideas to help you enjoy your geraniums from one year to the next. For more information about growing and caring for these popular plants, visit our geraniums hub page, packed with great resources. And do get in touch via our social channels to share your own favourite geranium plants with us – we love to hear from you.