Planting perennials properly and at the right time can determine whether they bloom the first year. Fall is considered the best time to plant perennials. I advise planting in fall, since hard-freezing weather may come early.
In general, you should plant at least six weeks before hard-freezing weather occurs. Most parts of Dawson County will have a hard freeze by late October or early November.
Fall-planted perennials continue to develop after planting. They produce an extensive root system during fall and spring, enabling them to firmly establish growth before hot weather begins. Plants continue to develop above ground parts, too. This development, although slow, accounts for the initiation of flower buds and stocky vegetative growth. This growth habit explains why well-branched plants emerge in the spring and flower profusely at the proper time.
Soil preparation is probably the single most important factor in growing perennials successfully. In addition to good drainage, provide good quantities of organic matter, a soil pH of 5.5 to 6.5, and fertilizer.
Add fertilizer based on soil test results, or use about 2 to 3 pounds of a complete fertilizer per 100 square feet of area. Add about 3 to 4 inches of organic matter into the soil to improve soil aeration and drainage, both of which encourage a healthier root system.
Soils amended with organic matter are much easier to plant and manage. Adding both lime and fertilizer when you prepare the bed insures an adequate fertility and pH level. Incorporate fertilizer, lime and organic matter into the soil to a depth of 8 to 12 inches. Incorporation can be accomplished by spading or tilling.
If plants are somewhat pot-bound at planting time, simply loosen the roots around the bottom and sides of the root ball and spread them out in the bottom of the planting hole. Cover and firm the soil lightly around the plant.
Two important factors to growing perennials successfully are watering and controlling weeds. Following planting, thoroughly water plants to settle the soil around the roots and dispel any trapped air. Supplying adequate water during the establishment period is essential, and periodic irrigation, especially during the summer, is necessary for plants to grow well.
Weeds crowd out perennials and destroy their attractiveness. Mulching and occasional weeding are two methods of combating weeds.
Mulch perennials lightly after planting to keep weeds down and prevent rapid moisture loss. Heavy mulching in the fall, however, encourages crown rot. Pine straw makes an excellent mulching material. I have successfully used weed block cloth under mulch.
You can fertilize established perennials in the early spring. Usually 2 or 3 pounds of a complete fertilizer per 100 square feet is adequate.
Clark Beusse is the Dawson County extension agent.