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Growing Geraniums

by Charles T. Behnke    

Geraniums are one of the most reliable plants grown in the home garden. They can be obtained in flower in late spring and will add color to the garden until frost. Some plants become quite large, with huge flowers; others are smaller. The new cultivars offer almost shatter-proof flowers that withstand wind and rain. Geraniums can be obtained as seedlings or established plants.

Set out plants in the spring after danger of frost is past. Geraniums that have been injured by cold temperatures will stand still and make little growth, often with red foliage. A late-May planting will be more satisfactory as the plants will establish better. Plant geraniums where they will receive sunlight for best flower production. Plants will grow in partial shade, but flowering is reduced even though foliage is produced. Select a site where water drainage is good. Geraniums will grow in almost any type of soil if well-aerated and porous. This means that 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.

Garden centers, greenhouses and retail outlets sell plants in the spring. These plants may or may not be in flower. Plants are generally available as rooted cuttings or as seedlings in plastic trays or pots. These are sure to grow because all you do is remove the container without disturbing the soil around the plant. Plants should be set in the soil no deeper than the depth they were growing in the pot. If possible, plant more shallow. If you plant too deeply, stem rot will usually kill the plant.

Once planted, firm the soil around the roots. Be careful not to injure the stem of the plant since this provides an opening for diseases to enter. Water thoroughly after planting. Liquid fertilizers such as 20-20-20, 15-30-15 should also be applied at the rate recommended on the package. Water after applying fertilizer, not only to get it into the soil where the roots of the plant can get it, but also to avoid burning. Any fertilizer that gets on the foliage of the plants should be sprayed with water.

Additional plants can be started from stem cuttings, or "slips." Remove these cuttings from the tip of the stems. They should be three to four inches long. Shorter ones can be taken if necessary. Strip off the lower leaves to facilitate sticking the cuttings in the rooting medium. Perlite, sharp sand alone or mixed equally with sphagnum peat moss is an ideal medium for rooting the cuttings.

Stick the cuttings an 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 three to four weeks. During the rooting period water sparingly. The trick to successful rooting is to run the cuttings on the dry side. When cuttings are rooted, place them in 4-inch pots. After the cuttings become established, which takes about a week, start fertilizing with a liquid fertilizer such as 20-20-20, 15-30-15 at one-half the recommended rate of application. Make monthly applications thereafter until the plants are planted outside in beds.

Pest problems are minimal with geraniums. Always keep fading flower stalks removed to reduce botrytis. Proper plant spacing will reduce botrytis on leaves that can sometimes build up during wet seasons.

Occasionally, geranium plants or single leaves will wilt for no apparent reason. This should alert the homeowner to a serious problem known as bacterial blight. Infected plants will more readily display this symptom under high (70 to 80 degrees F) temperatures. No sprays are available and removal of the plant from the site should be done immediately. Plants purchased from greenhouses have been started from clean stock plants or seeds thus eliminating many potential disease problems.

Gardeners often like to experiment and keep over their geraniums from year to year. This is possible 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 them, removing soil and hanging from the rafters in the basement on hooks. In general this method will work under high humidity, 85 to 90 percent and cool temperatures of 50 to 55 degrees F, but modern homes are too dry, thus causing dehydration of the plant. Because there is no sure way of knowing if this method will work in your home, try it and if successful you will have plants next spring.

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. Cutting type geraniums that perform well include in the reds: 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. Flowers are more toned to the pastel range of their hues. Keep plants 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 are favorable.


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