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Perennials should be planted in autumn

Published 7:24pm Monday, September 6, 2010

Many perennials live long prosperous lives and multiply readily with some care and have therefore earned the nick name “passalong plants.”
Planting perennials properly at the correct time can determine how well they will perform the first year or two. Here in the South, the preferred season to plant most perennials is considered to be fall.
For the Marengo County area, start planting perennials in October or as soon as the weather starts to cool down, but before the first hard freeze. This time frame gives the plant time to develop a good root system during fall and spring to enable strong development before hot weather begins.
This below-ground development, though slow, accounts for the rapid flowering and the stocky, well-branched growth observed in the spring.
Maintaining perennials is not a difficult task as long as the plants are carefully chosen and correctly spaced. Perennials do require routine maintenance, as do all plants in the landscape. The following are some of the routine tasks for perennials:
Carefully water after planting and during the first season while the perennial is becoming established.
Keep watch for weed infestation, especially perennial weeds in the first few years; maintaining good mulch should control annual weeds.
Cut the dead foliage to the ground after the first hard freeze in the fall or winter. This may be done later but should be done before new foliage begins to sprout in the spring.
Some marginal perennials such as salvias and Heucheras may need a light mulching of pine straw over the crown of the plant to extend the heartiness zone.
Divide most perennials periodically. Some require deadheading for continued bloom time and others benefit from staking or other form of support.
Fertilize perennials in the spring according to soil test results or apply 2 or 3 pounds of a complete fertilizer per 100 square feet. Do not fertilize perennials in the fall.
Most perennials eventually become overcrowded and require division. As perennials grow they expand in size by producing new growth away from the center of the crown. In time, the older center of the crown of the plant is no longer productive and dies out.  This can also cause poor flowering or overall lack of a healthy appearance to the plant.
Dividing perennials is done for any of three reasons:
•To rejuvenate the plant and stimulate new growth. Overcrowded plants compete for nutrients and water. Restricted airflow can lead to diseases. Dividing the plants into smaller sections reduces this competition and stimulates new growth as well as a more vigorous blooming.
•To control the size of the plant. Since plants grow at varying rates, division may be used to keep plants that spread rapidly under control.
•To increase the number of plants. Division is an easy and inexpensive way to increase the number of plants in your garden or “passalong” to friends.
Know your perennials and how they are supposed to grow in your area. It is best to divide perennials on cloudy, overcast days. Dividing on a hot, sunny day may cause the plants to dry out too fast. If the area to be worked on is dry, water the soil a day in advance. Dividing should also be planned when a few days of showers are forecast to provide adequate moisture for the new divisions.
The timing of perennial divisions also has a “general rule:” divide spring and summer blooming perennials in the fall and fall blooming perennials in the spring. Dividing the plant when it is not flowering allows all of its energy to focus on regenerating root and leaf tissue. How often to divide is something else; this is where your knowledge of your perennials comes in.  Some perennials such as garden mums need to be divided every year, where as others like ginger only need to be divided every 6 to 10 years.
To learn more about perennials and which ones are recommended for Alabama, visit our Web site www.aces.edu and search for “perennials.”
You may also read one of our publications titled “Herbaceous Perennials in Alabama” for plant recommendations at http://www.aces.edu/pubs/docs/A/ANR-0566/.

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