Nothing can make your landscape "Pop" like annual flowers.

 Annual flowers can provide landscaped areas with more seasonal variety and colorful accents than most other plants. The key to success with annuals is to plant only the area that can be adequately cared for. Remember, color can have more impact on the landscape than any other design element. However, nothing has a more negative impact than a poorly maintained color area.

 Soil preparation is perhaps the most important aspect in maintaining seasonal color areas. This begins with the addition of large quantities of organic matter to obtain optimum aeration, drainage and water holding characteristics. Generally speaking, beds should consist of at least 50% organic matter for best results. In addition, bed areas should be raised to a minimum of 4-6 inches to avoid "drowning" during wet, rainy weather. Since organic matter can be difficult to re-wet after excessive drying, a wetting agent can be used to achieve uniform water distribution throughout the soil.

Then just before or immediately after planting, apply a pre-emergent herbicide labeled for ornamental use, such as Treflan, and leave it undisturbed on the surface.

Fertilizer should also be incorporated into new beds. Select one where the ratio of N-P-K is 1:1:1 or 1:2:1 and apply according to label directions. Normal rate of application on new beds is generally 1 to 2 pounds per 100 square feet. On established beds, a soil test is recommended; normally, 1 pound per 100 square feet would be sufficient. Spade, rototill or otherwise mix well until uniform and level off.

Wait...don't try to jump the gun on planting! Most spring annuals can't be planted until after the danger of killing frost has passed; refer to the chart on hardiness for more details. Many warm season plants, such as periwinkles and caladiums, can not tolerate cool soil temperature. Delay planting until the medium reaches 70 degrees.

Many annuals, chiefly begonias, impatiens, coleus, alyssum, ageratum, lobelia, vinca, salvia and others, require little additional care. Their flowers fall cleanly from the plant after fading and do not need to be manually removed.

Others, such as marigolds, geraniums, zinnias, calendula and dahlias will need to have faded flowers removed. This is known as "deadheading" and not only keeps plants attractive but also discourages disease and keeps plants from going to seed so the plants will produce more flowers and look tidier. Deadheading can be done with pruning shears or sometimes with the fing

In most of Texas and the southwest, color areas can be changed out 2-3 times per year. Spring planted annuals are usually set out from late February through the first of June. A second planting of heat tolerant annuals, such as verbena, periwinkle or portulaca, is frequently used from June through the hot summer months. Fall planted annuals, like pansies and dianthus, are nerally set out when temperatures begin to cool off in late September-October. Managing color change outs is an important part of keeping plant materials looking their best.

Selecting a well adapted variety is the most critical element for success with seasonal color in the landscape. There are literally hundreds of varieties available but few will thrive in our stressful environment.

An excellent way to create more economical and sustainable color beds is to combine the annual flowers with flowering perennials. If designed properly, there will be year round "Action" and a reduced amount of seasonal planting.
For more information on the best ways to create more colorful impact in your landscape contact me at Cgreen.

Taken in part from the Texas A&M Horticultural Extension Website.

Mark Taylor
Cgreen Landscape and Irrigation
Building and maintaining your outdoor dreams.