Dusty Miller (Silver Ragwort) Plant Profile

Dusty Miller Plants

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Every flower garden needs a foliage foil to act as a contrast for its blooms, and dusty miller stands out as a neutral go-to plant for any color scheme. The silvery leaves of dusty miller look stunning when paired with cool purple and blue flowers, but also pair well with hot red and orange flowers. Even white flowers benefit from the glow of dusty miller in moon gardens. Although dusty miller is an old-fashioned annual that has been around garden centers for decades, the drought tolerance and pest-free nature of this plant make it worth revisiting for busy gardeners who want to add dazzle without fuss to their landscapes.

  • Botanical Name: Jacobaea maritima
  • Common Name: Dusty miller, silver ragwort
  • Plant Type: Hardy annual
  • Mature Size: 6 to 18 inches
  • Sun Exposure: Full sun
  • Soil Type: Average and well-drained
  • Soil pH: 5.5-6.0
  • Bloom Time: Summer
  • Flower Color: Yellow
  • Hardiness Zones: USDA growing zones 7-10
  • Native Area: Mediterranean region
Dusty Miller in Bloom
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Dusty Miller and Red Flowers
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Dusty Miller Close Up
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How to Grow Dusty Miller

Dusty miller is one of those plants that is full of surprises. One of its surprises is that it sometimes survives the winter in zones colder than it is hardy in. Gardeners report plants coming back in zone 5 or even zone 4 landscapes. Another surprise is the yellow flowers that sometimes make an appearance in the second growing season of dusty miller. Dusty miller is not marketed as a blooming plant, and while not all plants will produce the yellow fuzzy flowers, they increase the beauty on mature plants. What a bonus on an already lovely plant.

Light

Dusty miller needs full sun to stay compact. Plants growing in shade are leggy and produce fewer of the hairs that give them their silvery color.

Soil

Dusty miller plants adapt to a variety of soils, but good drainage is key for healthy plants. Whether your soil is on the rocky side or is characterized by clay, you can improve both your pH and drainage by amending it with compost.

Water

The fuzzy growth that gives dusty miller its sheen also helps plants stand tall in periods of drought. Like other plants that hail from Mediterranean climates, dusty miller can get by with occasional watering once it is established. A layer of organic mulch will make plants even less dependent on supplemental irrigation. One inch of water per week is enough to keep dusty miller growing strong.

Temperature and Humidity

As a Mediterranean plant, dusty miller thrives in hot, sunny climates. Excessive humidity isn't a problem as long as plants have adequate spacing and a position in full sun.

Fertilizer

Dusty miller plants are light feeders, and only need supplemental fertilizers in areas with very poor soil. In this case, it's better to feed and improve the soil at the same time by adding organic matter like manure or leaf mold.

Potting and Repotting

Pot up dusty miller with any commercial potting soil. Add a handful of peat moss to increase acidity. A layer of mulch on the soil will retain water and keep soil from splashing onto the leaves. It's time to repot when you see roots coming out of the drainage hole.

Propagating Dusty Miller

You can propagate dusty miller by cuttings in the spring, when plants are putting out the most rapid new growth. Cut off a six inch stem, and strip the leaves from the base. Dip in rooting hormone, and insert into moist potting soil. Keep moist and warm until new leaves begin to grow, then transplant as desired.

Varieties of Dusty Miller

The difference between dusty miller cultivars can be seen in how dissected the foliage is. Some varieties are very lacy and fine, while others are only slightly lobed. 'Cirrus' has broad leaves with scalloping on the edges. 'Silverado' has the fern-like foliage popular in many gardens. 'Silver Lace' has very fine foliage, as the name implies.

Silver Lace Dusty Miller
Dusty Miller Silver Lace. Akilina Winner/Getty Images 
Dusty Miller Cirrus
Dusty Miller Cirrus. Daniel Saumbraus/Getty Images 

Toxicity of Dusty Miller

Ingestion of dusty miller can cause minor illness like diarrhea or vomiting. The sap of the plant may also cause a rash.

Pruning

Dusty miller plants require no pruning to maintain their pleasing bushy shape. If you feel that the yellow blooms detract from the plants, shear them off as they appear.

Being Grown in Containers

Dusty miller looks fantastic in all kinds of containers, including hanging baskets and window boxes. The finely divided foliage looks so pretty combined with the trailing stems of petunias or million bells, and also make a handsome companion plant for other sun lovers like zinnias, pentas, or salvia. Keep your container in full sun, and water more frequently than plants growing in the ground, at least every other day in summer.

Growing from Seeds

Fill your garden beds with dusty miller by starting a flat of seeds six weeks before the last frost. Cover seeds lightly with sterile potting mix, and grow at 70 degrees Fahrenheit. You will start to see germination in about 10 days. Plant outdoors eight inches apart in pots, or 10 inches apart in the ground.

Common Pests/Diseases

Slugs enjoy snacking on dusty miller plants, especially in flowerbeds that receive frequent irrigation. Handpick the pests, or use beer traps to control their numbers. In addition to attracting slugs, excessive watering can cause root rot in dusty miller plants. This is more of a problem in clay soils, but you can prevent it by growing your dusty miller plants in containers or raised beds in areas with heavy soil.

Dusty Miller vs. Mugwort

Mugwort plants (Artemisia spp.) have the same silvery leaves and deeply dissected foliage as dusty miller. However, mugworts are more reliably hardy to zone 4, and also grow in a more mounding shape, in contrast to the upright form of dusty miller. Mugworts are even more drought tolerant than dusty miller due to their deeper perennial root systems, and are good candidates for the rock garden.