No garden is complete without colorful geraniums, and they’re so easy to grow that practically any gardener can successfully tend. Native to South Africa, geraniums can be grown right in the garden in USDA zones 8 through 11 where winters are mild, but they bloom even better when they are slightly root-bound (tightly packed, such as in a container), as long as they have good drainage. When grown in pots, geraniums can also be relocated at a moment’s notice, whether to show them off near an entry, to bring them indoors during surprise freezes, or to move them to a shadier spot during the hottest days of summer.
Types of Geraniums
These popular perennials are available in a multitude of species and hybrids, each with its own benefits. Some, like "zonal" geraniums, are grown for their variety of colorful flowers and velvety rounded leaves that feature bands of color arranged in zones (hence the name). Others, such as the handful of species known as scented geraniums, are beloved for the many different fragrances of their finely-cut leaves. Although the plant is not edible, the leaves of rose, mint, chocolate, and lemon fragrant geraniums can be used to impart delicate flavors to sugars, preserves, and drinks.
Whatever species or hybrid you grow, all geraniums need protection from winter freezes, summer heat, and soggy soil caused by overwatering. As long as you follow a few simple tips, geraniums will be some of the easiest and most prolific flowers you’ll ever grow.
Provide Full Sun
Geraniums need lots of direct sunlight to bloom well, so allow them to soak up those rays by placing them on the south side of walls, on patio tabletops, or as an accent in sunny areas of the garden. If you notice that your plant has stopped blooming in summer, don’t panic. Geraniums have a tendency to stop flowering during especially hot weather, so just move your plant somewhere where it will receive some afternoon shade if you live in a hot climate.
Mind the Moisture
Although geraniums do require moisture, they will likely rot if their potting mix stays wet for too long. To prevent this, water only when the top inch of the soil is dry, and make sure that moisture can easily drain away through holes in the base of the pot. Additionally, geraniums are relatively drought-tolerant plants—they can survive a fair amount of neglect, but should be never be allowed to dry out completely.
Keep Geraniums Blooming
To keep your geraniums in bloom, remove spent flower stalks periodically. To keep the plants bushy, full, and packed with flowers, pinch out new growth occasionally by pruning the tips of each stem with sharp, clean shears. Geraniums bloom best when they're somewhat root-bound, so repot your geraniums into larger containers only when necessary, and use a container only one size bigger than the previous one. Geraniums are heavy feeders, so fertilize your plants in the spring and summer with a balanced fertilizer, according to the product label's instructions. Stop feedings at the end of summer.
Protect From Cold Weather
Gardeners in USDA zones 8 to 11 can get away with merely covering their geraniums up on frosty nights, but everyone else should overwinter them indoors. Bring your geraniums inside before the first hard frost and place them in a sunny window, or let them go dormant in a cool, dark place.
Keep Them Healthy Indoors
Keeping geraniums in bloom indoors can add some cheer to a drab winter spent inside. The key is to keeping them healthy is maintaining temperatures above 50 degrees Fahrenheit, allowing the top inch or two of soil to dry out before watering, and keeping an eye out for any diseases or pests.
Watch Out For Spider Mites
Keep an eye on your overwintering geraniums for signs of a spider mite infestation. You may notice parched leaves, webbing, or tiny specks that resemble spiders when seen under a magnifying glass. Spider mites are best treated early, so move quickly as soon as you spot the problem. First, separate the affected geraniums from the rest of your plants and then treat them consistently and aggressively with neem oil. While it won't kill them immediately (it's not a poison), it will interfere with their biological systems, slowly ending the infestation. Soak both the plant and the top inch of the soil for best results.
Let Your Plants Go Dormant
If you’re lacking space indoors or don’t have a sunny enough window, you can let your geraniums go dormant for the winter by placing them in a cool (below 70 degrees Fahrenheit) and dark space, such as a garage or basement, as long as the temperatures don't dip below freezing. Let the soil dry out so that it remains only barely moist. Remove the leaves and flowers as they die off, and inspect the roots and crown occasionally for rotting parts, removing any rot with a sharp, sterilized knife.
After the last frost in spring, resume your normal watering cadence and begin placing your geranium container outdoors each day. You will want to harden off your plants for about a week, slowly moving them to sunnier positions so that the leaves can adapt to the extra sun without burning. After your plant is in-position and the weather no longer gets too cold for the plant (nighttime temps above 50 degrees Fahrenheit), you may begin feeding again.