ISU Extension News

Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915

6/19/03

FOR IMMEDIATE RELEASE

Contacts:
Linda Naeve, Reiman Gardens, (515) 294-8946, lnaeve@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033, jmcguire@iastate.edu

Plant "True Geraniums" in Your Perennial Garden

By Linda Naeve
Extension Coordinator
Reiman Gardens

If someone asked you to describe a geranium, would you describe a round-leafed annual plant that grows 12 to 15 inches tall with a cluster of red, pink or white flowers? If so, you are not alone. The plant we commonly refer to as geranium has had a mistaken identity for years. Geranium is the genus name for an entirely different group of plants. The geranium we are familiar with belongs to the genus Pelargonium and is not a "true" geranium. Both geraniums are beautiful plants, but are used differently in the garden.

There are more than 250 species in the Geranium genus and so it is a surprise that so little is known about them. They are sometimes referred to by their common name - "cranebill geranium." They were given that name because the shape of the seed head or fruit resembles the bill of a crane.

Hardy geraniums are underused in Midwest gardens. They are hardy, long-lasting and bloom reliably for several weeks. The plants are covered in blooms from early June through July and will always have a few flowers on the plant throughout the summer. The flowers are simple, nickel- to quarter-sized in rose, pink, magenta or blue. Depending on the species, the plants grow 6 to 30 inches in height. The leaves on hardy geraniums are small, round, and deeply lobed.

The most common garden species in the United States is probably bloodred geranium, Geranium sanguineum. They are hardy from USDA Zones 3 to 8 and grow in mounds up to 12 inches in height. They make a good ground cover under tall shrubs, such as hawthornes, lilacs and viburnums. Hardy geraniums also look beautiful in the front of a border in full sun or partial shade. They even look beautiful in a rock garden. The foliage of bloodred geranium turns a stunning red to maroon after the first hard frost.

Hardy geraniums require very little care and attention. A leaf spot infection may appear on the leaves under hot, humid conditions, but fortunately, it is not a serious problem. If the plants become a bit leggy in mid-summer or are infected with a leaf spot, cut them back to about six to eight inches in height. The plants will thank you by sending up a new flush of growth and flowers.

Another excellent hardy geranium for perennial gardens is Geranium x 'Johnson's Blue.' It is an excellent hybrid between G. himalayense and G. pratense. It forms 15- to 18-inch mounds covered with vivid blue, cup-shaped flowers. It blooms in June and then goes somewhat dormant in hot weather.

Hardy geraniums are easily divided in the spring to give you more plants by digging to the side of the clump and removing a side shoot with a strong root system.
You can see several beautiful plantings of hardy geranium at Reiman Gardens. Bloodred geraniums have covered an area to form a beautiful ground cover in the Dunlap Courtyard near the Mahlstede Horticulture Learning Center. 'Johnson's Blue' geraniums are currently making a bold statement in the Patty Jischke Children's Garden and the Town and Country Garden.

To learn more about the Reiman Gardens at Iowa State University visit us on the Web at: http://www.reimangardens.iastate.edu/.

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Editors: A color photo, suitable for publication, is available at right. Click on the thumbnail photo to go to the fullsized photo. The picture's fullsize photo is 476K.

Caption: Johnson's Blue Geranium


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