IDENTIFICATION — At first glance, this weed could be a tall, striking ornamental for the back of your border. But its soft gray foliage and tall spikes of yellow flowers can be deceiving. It could take over your garden. Just one common mullein plant is capable of producing about 180,000 seeds, which can remain viable in the soil for 100 years or more.
Common mullein, also known as woolly or flannel mullein, is a biennial. The first year it’s a low rosette of gray feltlike leaves that can be more than a foot long. In its second year of growth, cylindrical spikes of small cup-shaped yellow flowers appear. The flower stalk can be up to 8 ft. tall and often blooms from June until early October. Both the leaves and the stem are covered in soft woolly hairs. Spent flower stalks remain standing through the winter.?
FAVORITE CONDITIONS — Found throughout much of North America, common mullein prefers lean, dry sandy soils. But it will adapt and grow just fine in richer soils, too. And like many plants with gray woolly foliage, common mullein needs plenty of sun to reach its full size. Some of its favorite spots are gravelly areas like ditches, railroad embankments or along driveways. Occasionally you’ll find it growing in vacant lots, fence rows or old garden areas that are rarely cultivated.
CONTROL — You can easily pull common mullein plants out by hand, especially in loose or gravelly soil, because they usually have a single taproot. But if you can’t pull a mature plant, make sure to remove any blooms and seed capsules before they spread. To prevent any unwanted seedlings, dispose of the removed stalks in plastic bags that you send away in the trash.
Herbicides are especially effective on young plants. Apply glyphosate, a nonselective herbicide, to the foliage while the plant is actively growing in spring.