Growing Geraniums in Containers

Ivy-leaved geranium flowers cultivated in a greenhouse
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No garden is complete without geraniums, and they’re so easy to grow that no gardener should be caught without one. Geraniums can be grown right in the garden in zones 8-11 where winters are mild but do even better in containers where they receive the drainage and slightly root-bound conditions that they prefer to bloom their best. 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 in the hottest days of summer.

These South African perennials in the Pelargonium genus are available in a multitude of species and hybrids, each with its own assets. Some, like the 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. While they are not edible and must be removed before eating, the leaves of rose, mint, chocolate and lemon fragrant geraniums can be used to impart delicate flavors to sugars, preserves, and drinks, among other things. Whatever species or hybrid you grow; all geraniums need protection from winter freezes, summer heat, and soggy soil caused by overwatering. However, as long as you follow a few simple tips, geraniums will be some of the easiest and most prolific flowers you’ll ever grow. Here are the rules for growing geraniums in containers.

Provide Full Sun

Geraniums need lots of direct sums to bloom well, so let them soak up those rays by placing them on the south side of walls, on 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 blooming during hot weather, so try placing it where it will receive some afternoon shade if you live in a hot climate.

Mind the Moisture

While geraniums do require moisture, they will likely rot if the potting mix stays wet for too long. To prevent this, only water when the top inch of the potting mix is dry, and make sure that moisture can easily drain away through drainage holes in the pot. Geraniums are relatively drought-tolerant and will survive a fair amount of neglect, but should be watered before the roots are allowed to dry out completely.

Keep Geraniums Blooming

To keep geraniums in bloom, remove spent flower stalks periodically. To keep plants bushy, full and packed with flowers, pinch out new growth occasionally by pruning the tips of each stem with sharp, clean pruners. Geraniums also bloom best when somewhat root-bound (meaning that their roots are snugly packed into the container) so re-pot geraniums only when necessary, and use a container only one size larger than the previous one. Geraniums are heavy feeders, so fertilize in spring and summer with a balanced fertilizer, according to label instructions. Stop feedings at the end of summer.

Protect from Freezes

Gardeners in zones 8-11 can get away with merely covering their geraniums up on frosty nights, but everyone else should overwinter them indoors. Bring your geraniums indoors before the first hard frost and place them in a sunny window to brighten up your home, or let them go dormant in a cool, dark place.

Overwinter Geraniums Properly

Keeping geraniums in bloom indoors is a great way to add some cheer to your winter. The key is to maintain temperatures over 50 degrees, allow the soil’s top inch or two to dry out before watering and stay on top of any diseases or pests. Keep a watchful eye for spider mites especially. Spider mites can be identified by parched leaves, webbing, or tiny dark specks that resemble spiders when seen under the magnifying glass. They are best treated early—as soon as you spot the problem. First, segregate them from the rest of your plants and then treat them consistently and aggressively with ​Neem oil spray.

If you’re lacking in space or don’t have a sunny window, you can let your geraniums go dormant for winter by placing them in a cool (below 70 degrees) and dark space such as a garage or unheated basement, as long as it doesn’t get below freezing; and letting the soil dry out so that it remains only barely moist. Remove leaves and flowers as they die off, and inspect the roots and crown occasionally for rotating parts. These should be removed with a sharp and sterilized knife. After the last frost in spring, resume normal watering (when the top inch is dry) and begin placing your geranium outdoors each day. You will want to harden off your plants for about a week, slowly moving it to sunnier positions over the course of a week so that the leaves can adapt to the extra sun without burning. Once the plant is in position, you may begin feeding again.

Follow the tips above and you’ll agree that geraniums are some of the most carefree and rewarding flowers you’ve ever grown in the container garden.