Annual flowers provide a splash of color to brighten the summer season. Modern breeding has resulted in an increased range of color, form and texture for a diverse palate.
These vigorous plants can be easy to grow but do require maintenance to keep them happy and flourishing. In the Kansas City area, an even supply of water is a must. The other important requirement is a constant supply of nutrients, which can be provided from timely fertilization.
Annual flowers have a very short period of time to grow: Their life is over with autumn’s first frost. Maximum flowering is achieved when they have enough nutrients for continual growth. If the nutrients run out, so does the growth that produces the new flower buds.
Annual flowers should be fertilized monthly throughout the growing season. The first application should be made at planting to give them a jump-start. Continue with a monthly feeding through September. September and October can be some of the best months for color as the daytime and nighttime temperatures are more conducive to growth. Cooler temperatures usually bring more intense flower color.
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As with many gardening chores, there is more than one way to accomplish the task. A water-soluble fertilizers that is diluted in water and poured on the plant is one option. Be sure to read and follow the directions. Water-soluble fertilizers are usually applied more frequently than once a month. They work by providing a lower dose more often.
One fallacy with some of these products is the recommendation that the mixture be sprayed on the foliage. Leaves really do not absorb nutrients, the roots do. So aim these applications at the soil.
Time-released granular products also can be used. These are slow release and feed the plants over time. Once again, there is a fallacy in the application recommendations. They do last the length of time stated on the package under cool soil temperatures. But under typical summer KC heat they release nutrients more rapidly. A good rule to follow is to apply more frequently by cutting the recommended application frequency in half.
The simplest and most cost effective-garden fertilizer is probably already sitting in the garage. Based on our region’s average soil fertility, use a fertilizer such as 30-0-0 or 25-5-5 at the rate of 2 to 3 tablespoons per 10 square feet of bed. Spread evenly over the planting and water it into the soil thoroughly after each application.
No matter which option you chose, just do it. The timely feeding will promote new growth and your flowers will be bigger, bolder and showier than ever.
Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Got a question for him or other university extension experts? Email them to firstname.lastname@example.org or visit KCGardens.KansasCity.com.