Geraniums – Reliable Performers with Great Appeal

Janice M. Weber

Dekalb County Master Gardeners

Geraniums have come a long way since the days of Granny's common red-orange garden variety. Today's colors and foliage have pizzazz!

The flowers can range from bold to dainty, or even tulip shaped. The leaves can be variegated, scented, or trailing. Geraniums are reliable performers that can be bought already in bloom, ready to reward you with color until frost.

It's tempting to start planting them when the weather begins to warm and eye-catching colors make their appearance. But geraniums will be injured if planted too early. They will stop growing for a while and their foliage will turn red. Wait until night temperatures stay above 50 degrees, sometime after May 20.

Most geraniums love sun, but they also appreciate a little late afternoon shade. Select a site where water drainage is good because geraniums don't like wet feet. Heavy clay soils need organic matter added each year. Work in about an inch of peat moss, compost, or rotted manure. Use fresh potting mix in containers.

Plant your geraniums no deeper than they were growing in their pots and space them at least 12 inches apart. Water them the first time with a starter solution plant food. It's high in phosphorus for root growth, which will get your plants off to a good start.

Geraniums look nice in front of shrubs, massed in beds and in containers. They add color to the perennial bed after the perennials have finished blooming. Remove old flowers by breaking them off at the stem. This will encourage new buds to develop faster.

Most geraniums do better if kept somewhat dry. Water them well when the soil becomes dry to the touch about an inch down. Yellowish leaves are usually a sign of overwatering. Underwatering causes the leaves to become brown or crisp.

Insect problems are minimal. If a cloud of white appears when the plants are disturbed, spray them with an insecticidal soap. Those are whiteflies. Deer will eat just the flowers. During wet summers plants may suffer from botrytis, a bacterial rot on leaves and flowers.

If you want to keep your favorite geraniums from year to year there are two recommended methods. The first way is to dig up the plants, trim them back one-half their original height, repot them and place them in a sunny window. Pinch back the new growth to keep the plants symmetrical and well branched.

The second method is to snap off 3-4 inch stems in late August. Strip off all but about 3 top leaves and trim any large remaining leaves to reduce moisture loss. Dip the cut ends in rooting powder and set them in damp sand, a potting mix, or a seed-starting medium in small pots. Place the cuttings in a bright spot out of direct sun and sprinkle the medium with a little water every few days.

The trick to successful rooting is to keep the cuttings on the dry side. They will wilt a little, but usually start to root in about three weeks. You will see new top growth when this happens.

Repot the rooted cuttings in 4-inch pots and gradually introduce them to a sunny window. Make monthly applications of 20-20-20 or 15-30-15 fertilizer at one-half the recommended mixture rate.

Some people save geraniums by digging them up, removing the soil and hanging them in the basement. But modern homes are usually too dry for this to work. It takes 85 to 90 percent humidity and cool temperatures of 50 to 55 degrees.

There are many types of geraniums. To save money purchase the "seed geraniums" available at most garden centers. The flowers may be a little smaller and the leaves are plain, but they are steady bloomers.

Ivy-leafed geraniums have succulent, glossy leaves and trailing stems that look good in containers. They do best in an east or north exposure and like to be kept evenly moist. They don't do as well during periods of high humidity or temperatures over 85 degrees.

Alpine geraniums are a trailing type that is very heat tolerant. They produce masses of spidery flowers that look wonderful in hanging baskets. You've seen them in photos spilling from the window boxes in Swiss villages.

Geraniums with highly variegated leaves do best with a little shade. Scented geraniums have unassuming flowers. They are prized for their fragrances when the leaves are touched. Stellar geraniums have striking cut leaves and star-shaped flowers. Both like a little afternoon shade when it's hot.

Martha Washington or Regal geraniums have large, showy flowers. They require cool nights of 60 degrees or lower to stay in bloom. They are best grown in pots, which can be moved out of hot sun. Keep them evenly moist. They need 50-55 degrees for six weeks in the winter to bloom the next year.

If you still think of geraniums as overly familiar and common, check out the dazzling variety of colors and styles available at nurseries next spring or visit a geranium specialist, such as Shady Hill Gardens in Elburn, to see the unusual novelty types. You'll soon have many new favorites.