Pansies must be planted on certain dates to reach their full potential

With summer ending, many of fall blooming plants are starting to appear at garden centers. We are very fortunate to have numerous plants we can use in our landscapes to provide us with color during the fall and winter months.

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Pansies, violas, snapdragons, flowering kale and cabbage are some of the more common plants we can use. We have to know these plants, however, in order to get the best color from them.

Due to intensive plant breeding, pansies are available in many colors, from white to rich gold, purple, red, rose, maroon, orange and violet, with many shades in between. You also can choose from solid colors (called "clear" faced pansies) to blotches (having a darker, contrasting center, often referred to as "faced" pansies), two-tones and all sorts of color blends and pastel shades. Some varieties have petals with crinkled or ruffled edges. Others have large flowers up to 4 inches in diameter. There are more than 300 varieties of pansies on the market.

In our area, the best time to plant pansies is from the middle of October to the start of November. The reason for these specific planting dates is that pansies require soil temperatures between 45 and 65 degrees for best growth. Pansies planted after soil temperatures go below 45 degrees show stunted, pale green leaves, little growth and, most importantly, little or no flowering.

Cold-stressed root systems are less efficient in taking up nutrients. During very cold weather, when soil temperatures fall below 45 degrees, plant roots literally shut down.

On the other hand, pansies planted too early and exposed to warm temperatures often appear yellow; the stems stretch and the new growth will appear as small rosettes at the ends of stems. As a result, the plants flower poorly and become more susceptible to frost damage and disease.

Fertilization requirements of pansies differ from other types of seasonal color plants. Avoid using fertilizers containing high amounts of slow-release ammoniacal nitrogen, which can weaken the plant and make it more susceptible to winter injury.

The best fertilizers to use will contain formulations with nitrogen derived from potassium nitrate, calcium nitrate, and perhaps magnesium nitrate.

The soil needs to have good drainage in order for pansies to do their best. Pansies don't like wet feet. If the soil is holding too much moisture, the pansies will get root rot. Use fine ground pine bark or some other material to improve the drainage of the soil. Soils that hold moisture should be raised 6 to 8 inches above their existing level to help with drainage. Pansies work well in containers because the soil in containers drains well.

Also, carefully monitor irrigation and try to keep pansies slightly on the dry side. This will help to harden the plants so they can better withstand cold weather. It is best to water during the day so the plant has time to dry before night.

Diseases that cause problems in pansies are crown and root rot, black root rot and Botrytis blight. Crown and root rot is the most significant disease on pansies. It is most active in warm, wet weather and thus occurs on pansy beds in the fall and late spring. The fungus infects the plant at or just above the soil line. The crown lesion begins to rot and the entire plant dies.

The next most damaging disease is black root rot, which attacks the fine feeder roots of the plant. An infected plant will be yellow in color and stunted.

The last disease is Botrytis blight, an airborne fungus that attacks almost any flower and dead, dying or damaged plant tissue. It is most common on plants that have high rates of fertilization, death of lower leaves, low light intensity, frequent watering, early flower production, and plants that are crowded.

You can control most of these problems by managing your pansy beds properly.

Columbia County Extension Agent Charles Phillips can be reached at (706) 868-3413 or by e-mail at charlesp@uga.edu. The Extension Web address is www.ugaextension.com/columbia.