Senecio cineraria is commonly known as dusty miller, white diamond dusty miller, or diamond bedder dusty miller. This plant is native to Mediterranean countries including the Spain, France, Italy and Greece. In the United States it is hardy in zones 8 through 10. Dusty miller can be used as an annual in both container plantings and garden beds. Distinguished by delicate silvery-white foliage it stands out, and adds both texture and interest in the garden.
The leaves of the dusty miller plant are woolly in appearance, and they have a fern-like look. This plant has a low mound-like growth pattern, and generally reaches a height of approximately 12 inches--and a spread of a little over a foot. Plants grown as a perennial produce yellow flower heads that are 1 inch in circumference in their second year.. Flower heads form in clusters that are around 4 inches across. However, since dusty miller is used mostly as an annual flowers are rarely seen.
Dusty miller is hardy in zones 8 to 10. "Mediterranean climates are found in only five places on Earth: California and northern Baja California, the basin of the Mediterranean Sea, southwestern Australia, the western cape of South Africa and the central coast of Chile," notes The Nature Conservancy. In these areas dusty miller can be grown as a perennial shrub due to the hot, dry summers and mild, wet winters. In other areas, the plant is grown as an annual.
Dusty miller should be grown in full sun, and in well-drained soil. It grows well in most soil conditions. Although drought tolerant it will need to be watered if extreme drought conditions exist for a long period of time. If the plants become leggy you can prune or pinch them back. Pinching back or pruning promotes growth, and the plants will become bushier.
Whether planted in containers or in garden beds, an application of a time-released fertilizer with an NPK ratio of 10-10-10 improves plant health and makes them better able to fight off pests and disease. An application of a time-released fertilizer that is designed specifically for flowers usually lasts for 3 months. The first application can be applied in early spring, and the second application can be applied in mid-summer.
The silvery foliage of dusty miller provides an interesting contrast to the colorful blossoms of other annuals and perennials. It can be used in container plantings as well as window boxes and hanging baskets. Dusty miller can also be used as a border in flowerbeds. It is often seen in cut flower arrangements.