What Are Flush Flowers?

Herbaceous Annuals and Perennials

• Deadheading is the practice of removing spent flower heads before they go to seed. It encourages the plant to produce new flowers, extending the blooming period for both annuals and perennials. Pinching, another pruning technique, can help create denser growth with more flowers. To pinch a plant, take the last bud on a stem and the pair of leaves just below it between your thumb and forefinger and pinch the stem off. You can control and extend the blooming flush by pinching one-third of the plant one week and another one-third each of the next two weeks.

Flowering Shrubs

• Flowering shrubs fall into two categories, spring flowering and summer flowering. Shrubs that flower in the spring flower on growth started in the late summer and fall. Pruning these shrubs in the fall, winter or spring removes all the flower buds, so wait until after flowering and prune in early summer. Shrubs that flower in the summer flower on new growth initiated that spring. They can be pruned any time after flowering until new growth begins in the spring. Old, woody growth is less likely to flower; cutting it out will initiate succulent growth and increase blooming. Deadheading is recommend by the Colorado Master Gardener's Program for both spring- and summer-flowering shrubs.

Fertilizing for Flowers

• Annual and perennial flowering plants and shrubs require different fertilizer application schedules. Fertilize your annual flower bed prior to planting and then again six to eight weeks later. Late-blooming annuals may require a third application six to eight weeks after the second to encourage fall blooms. Fertilize perennials in the spring, just as new growth begins. Some long-flowering perennial plants may require a second application six to eight weeks after the first. Fertilize shrubs in the spring as new growth begins. Use fertilizer with either equal amounts of nitrogen and phosphorous, or less nitrogen than phosphorous. Nitrogen stimulates leaf growth, while phosphorous promotes flowering.

Large Blooms

• Some gardeners prefer a few, large blooms to several, smaller blooms. Grow larger flowers on your perennials and shrubs by pinching the lateral, or side, buds and not the terminal, or end, bud. The plant will put all of its energy into those few flowers, making them larger. According to Penn State University, thinning your perennials and shrubs may also increase flower size. Cut one-third of the plant's stems back to the ground to increase light penetration and reduce old growth. Since less of the plant's energy is used for leafy growth, flower size may increase.