Geraniums (Pelargonium spp.) are one of the most popular summer flowers, and though they’re technically perennials, most people grow them as annuals. But if you take a few simple steps this month, you can overwinter your geraniums and grow them again next summer.
Overwintering geraniums is a great option if you’re looking to save money. Instead of having to buy new plants at the nursery every year, you can keep on growing the same plants year after year. As autumn approaches, now is the ideal time to start prepping your geraniums for the cold season.
Here’s what you need to do with geraniums in September to help them survive and thrive in your garden again next summer.
1. Remove Dead Flowers & Foliage
The first step in preparing your geraniums for winter is cleaning up any dead foliage or faded flowers. Use a pair of sharp, clean pruners – Editor-in-Chief Melanie loves her Felco pruners from Amazon – to cut off any dead flower heads or brown leaves and stems.
You can also deadhead faded geranium flowers by hand. The spent blooms are easy to snap off with your fingers. Just find where the stem holding up the flower meets the main stem of the plant and gently snap it off. You can put the dead flowers and foliage into your compost bin as long as it doesn’t show any signs of disease or pests.
2. Take Cuttings to Propagate
September is a great time to take cuttings to propagate geranium plants and expand your collection next summer. Even if you overwinter your existing plants, it’s nice to have backup plants that you can either share with friends and neighbors or fill bare spots in your garden next year.
To propagate geraniums, use a sharp, clean pair of pruners to cut a 4-5 inch (10-12 cm) section from a non-flowering stem. Be sure to cut just below a leaf node to encourage new root growth. You can also encourage roots by using a rooting hormone powder like this one from Walmart.
Stick the cuttings into potting mix or perlite in a container with drainage holes. Keep the potting mix moist and place the container in a frost-free location over winter – a greenhouse is an ideal spot. In spring, after the last chance of frost, plant your new geraniums in individual containers or in the garden.
3. Move Plants Indoors
Before the first frost arrives in fall, move your geraniums indoors or into a greenhouse. Before taking plants inside, though, check for any signs of pests or diseases to prevent spreading them to your other indoor plants. If you find pests on your geraniums, use a neem oil or insecticidal soap spray – both of which are available on Amazon – to kill them before bringing plants indoors.
Choose a location indoors that has bright indirect sunlight and is away from heating vents. Hot, dry air from indoor heating can cause geraniums to crisp up and turn brown over winter. Clustering multiple potted plants together can help raise the relative humidity in the area and prevent geraniums from drying out too much.
4. Reduce Watering & Fertilizing
As the season draws to a close and geraniums move towards winter dormancy, it’s time to reduce watering and fertilizing. Feeding geraniums at this point in the year can stimulate new growth when plants should instead begin hunkering down and saving energy for next spring and summer.
Watering geraniums too much in September can also spur on new growth, but it can cause root rot as well. Potted geranium plants need less water during fall and winter than they did during the heat of summer. The temperatures are more mild, which means moisture remains in the soil longer.
Only water plants once soil has completely dried out. If you’re in doubt about whether or not your plant needs more water, a soil moisture meter like this one from Amazon, gets rid of the guesswork.
