This is the time of year when flowering annuals strut their stuff. Make the most of these blooms and lengthen their colorful display with just a little extra care.

Watering: Most annual flowers have shallow root systems, so dutiful attention to watering is important, especially with flowers in containers. Keep the soil slightly moist, except for drought-tolerant plants. Don't depend on the appearance of the potting soil to tell you if it's dry or wet. Use a finger to feel down an inch or two. If you aren't diligent and the plants wilt on a regular basis, flower production will lag.

Excessively moist soil also is a problem. I once had a problem with the flowers in a wine barrel planter -- the soil seldom needed watering. I supposed it was because there were no holes in the bottom of the barrel, although my other thriving barrels didn't have drainage holes either. Finally, I figured out that because the lawn sprinklers reached this particular planter, my flowers were drowning in wet soil. I moved the planter, dried out the soil, but the plants never recovered.

Hanging planters often require more frequent watering than other containers, especially if they're in full sun or are moss baskets, where the soil and roots are more exposed. Baskets should be watered from the top when the first 1/4 inch of soil becomes dry. In our region, this can be as much as twice a day.

Dead-heading: This is the removal of spent flowers from flowering annuals, perennials and shrubs. Annual flowers usually look better and keep flowering longer if you regularly remove old flowers before they set seed. I like to use a petite pair of flower pruning sheers to snip off the spent blooms. This can be tedious with lots of flowers. For grooming these plants, like my gigantic sage, I use a small electric hedger. Right after flower removal with the hedger, the plants look ragged but within a week or two new growth covers the cut ends and the plants look much better.

Many newer varieties of annual flowers don't require dead-heading. They either don't have seeds or they were bred to be "self-cleaning." The flowers of these plants drop off and fade away on their own.

Petunias and some other flowering plants have a tendency to become leggy and unkempt as the season grows longer. These plants benefit from having their stems cut back by half in mid-summer once flowering slows. Again, some of the newer varieties of petunia don't need this special attention.

Fertilizing: When planting annual flowers in beds, a fertilizer that provides slow-release nitrogen should be mixed into the soil before planting. Plants in containers depend on gardeners to supply their nutrition. Many potting mixes contain a slow-release fertilizer may not last the entire season. If your potting mix did not contain a slow-release fertilizer, you can apply a water-soluble fertilizer once a week. Use the per gallon rate recommended on the label. If only a monthly rate is provided on the label, divide this by four and use that amount once a week when you water. You also can use a water-soluble fertilizer if you suspect your slow-release fertilizer has dissipated.

The belief that phosphorus fertilizer stimulates flowering and root growth is a myth. If your annuals are growing well but not flowering satisfactorily, the problem may be a lack of light. If the plants aren't growing or flowering well, the limiting factors could be light as well as soil moisture, nitrogen, potting soil or drainage.

Annual flowers are a delight. To keep them looking their colorful best, give them a little extra attention through the summer.

* Marianne C. Ophardt is a horticulturist for the Washington State University Extension Office in Benton County.