Geraniums are one of the most reliable plants in the home garden. They can be obtained in flower in late spring and will add color to the garden until frost. The new cultivars offer almost shatter-proof flowers that withstand wind and rain. Geraniums can be obtained as seedlings or established plants.

Planting:

Set out plants in the spring after danger of frost is past. Geraniums that have been injured by cold temperatures will produce little growth and the foliage will often be red. Planting in late May is preferable for the most productive plants. Plant geraniums where they will receive sunlight for best flower production. Select a site where water drainage is good.

Geraniums will grow in almost any type of soil if well-aerated and porous. Heavy clay soils should be improved by adding organic matter each year. An inch of coarse sphagnum peat moss, partially-rotted manure, or compost spaded in when preparing the beds is ideal.

Geranium plants are generally available as rooted cuttings or as seedlings in plastic trays or pots. Plants should be set in the soil no deeper than the depth they were growing in the pot. If possible, plant more shallow--stem rot can kill plants if they are planted too deeply. Once planted, firm the soil around the roots. Be careful not to injure the stem of the plant, as this provides an opening for diseases to enter. Water thoroughly after planting.

Liquid fertilizers such as 20-20-20 or 15-30-15 should also be applied at the rate recommended on the package. Water after applying to ensure that the fertilizer reaches the roots and to avoid burning. Any fertilizer that gets on the foliage of the plants should be sprayed with water.

Cuttings:

Additional plants can be started from stem cuttings, or "slips." Remove cuttings, 3 to 4 inches in length, from the tip of the stems. Shorter cuttings can be taken if necessary. Strip off the lower leaves to facilitate sticking the cuttings in the rooting medium. Perlite or sharp sand alone or mixed equally with sphagnum peat moss is an ideal medium for rooting cuttings. Place cuttings 1 inch deep in the medium and water thoroughly. Place container in a north or east window until rooted. Rooting occurs best with soil temperatures of 72 to 75 degrees F. This generally takes 3 to 4 weeks. Water sparingly during this rooting period--the trick to successful rooting is keep the cuttings fairly dry. When cuttings have rooted, place them in 4-inch pots.

After the cuttings become established (approximately 1 week), start fertilizing with a liquid fertilizer such as 20-20-20 or 15-30-15 at one-half the recommended rate of application. Make monthly applications thereafter until the plants are planted outside in beds.

Problems:

Pest problems are minimal with geraniums. Always keep fading flower stalks removed to reduce botrytis, which can be a problem during wet seasons. Proper plant spacing will help to minimize botrytis. Bacterial blight can be a serious problem on geraniums--usually evidence when the plant or single leaves wilt for no apparent reason. Infected plants wilt most readily under high (70 to 80 degrees F) temperatures. No sprays are available and the plant should be removed from the site immediately.

Propagation:

It is possible to keep geraniums from year to year by taking cuttings in late August and rooting them as discussed earlier. Plants can also be dug, trimmed back to one half their original height, repotted and placed in a sunny window for the winter months. Some people also save geraniums by digging up the plants, removing soil and hanging from the rafters in the basement on hooks. This method requires high humidity (85 to 90 percent) and cool temperatures (50 to 55 degrees F).

Cultivars:

There are many types of geraniums. The majority today are produced from seed. Look for plants in these seed-propagated families - Ringo, Bandit, Elite, Orbit, Pinto, Multibloom and Lone Ranger - for good results. Red cutting type geraniums that perform well include Kim, Mars, Tango, Yours Truly and Sincerity. Pink and other varieties include: Cherry Blossom, Helena, Katie, Pink Expectations, Pink Satisfaction and Rio.

Unusual geraniums such as ivy-leafed, scented and Martha Washington can also be grown by homeowners. Ivy-leafed geraniums display a characteristic of trailing stems that make them ideal for containers. Keep evenly moist in a east or north exposure. Ivy types do not tolerate temperatures above 85 degrees F for long periods. Scented type geraniums should be grown in full sun to develop the volitile leaf oils. Flowers are less significant with this group, but the soft scented leaves give fragrant oils that are useful in sachets. Martha Washington or Regal geraniums are sold in early spring and require cool temperatures (60 degrees F and below) at night to stay in bloom. Warm summer temperatures will cause flowering to cease until fall, when temperatures become favorable.

Adapted from Charles T. Behnke, Ohio State University Extension, 2000