Dusty miller (Senecio cineraria) is a shrubby plant valued for its fuzzy, silvery-white leaf that offers stark contrast to colorful blooming flowers and bright green foliage. Dusty miller, that attains heights of 8 to 15 inches in adulthood, based on the variety, is a tender perennial suitable for growing in U.S. Department of Agriculture plant hardiness zones 8 through 10.
Pinching the new development of youthful dusty miller plants early in the summer delays blooming slightly, but the consequence of the simple task is complete, bushy growth and a healthy, compact plant. To pinch dusty miller, use your fingernails or garden clippers to remove 1/2 to 1 inch in each developing tip. New stems develop from each pinched spot.
A healthy midsummer pruning rejuvenates a tired dusty miller plant and keeps it looking healthy and full for the remainder of the season. There are two ways to do a midsummer pruning. The fastest method is to shear the whole plant by about one-third of its span. Although thriving is delayed by a few weeks, the plant comes back healthier than previously. A less painful way to prune in midsummer is to prune a long stem every day or two, which also results in a more natural look. Make each cut just above a leaf or leaf node, and the plant will send out new development at each cut.
Dusty miller is grown mainly for its striking leaf; however, clusters of long-stemmed, creamy yellow or white flowers develop on the plant in summer. Most gardeners prefer to remove the flowers, as the somewhat unsightly flowers redirect energy in the leaf. Pinching back the blooms the moment they looks encourages healthy development of the leaves.
Bright sunlight brings out the very best in dusty miller. In color, the leaf is sparse, loose and more likely to develop into long and leggy, while plants grown in sunlight are leafy, dense and brilliant white. In mild climates, dusty miller stays attractive until after the first light frost and then reappears in spring. In this case, the plant frequently becomes shrubby and reaches heights up to two feet. In cooler climates of USDA zone 7 and under, dusty miller is grown as an annual.