Good time to use the "Garlon spritz" on mullein

Mullein (Verbascum thapsus) is a biennial invasive weed in the figwort family. The first year it is a low-growing rosette and the second year it sends up a tall, ugly, flower stalk which produces lots of seeds. Although it does not compete well, it gets established well in bare areas such as generally exist in early prairie plantings. Although mullein is frequently used as a herbal, it is definitely undesirable in any natural area and should be eradicated.

Yesterday Kathie and I ran across a large patch of mullein in one of our open savannas (Unit 11A). It seemed a little strange, since the area had been a large patch of colorful bergamot in mid-summer. However, the bergamot seed heads were still present but the foliage had senesced and the soil was bare, ideal conditions for mullein to get established. Although it is possible that next year the mullein will be out-competed, we weren't taking any chances, especially since conditions were now ideal for the Garlon spritz technique. Within fifteen minutes we had finished the job.

For this work we used 20% Garlon 4 in bark oil, with an oil-soluble red dye as a tracer. Note that the whole plant does not have to be sprayed, only the center of the rosette. It takes about 10 seconds per plant. You won't see much of a response this time of year, but the roots will be killed as soon as growth starts next spring.

Hand spray bottle next to sprayed mullein rosette. Only the center needs to be sprayed.

Most people control mullein by digging the plant up. This may be necessary for tall second-year plants, but herbicide is ideal for first year plants.

At the same time we were doing this mullein patch we basal barked scattered buckthorn and other woody invasives. One of the great advantages of the Garlon spritz technique is that the same mixture also works for basal bark of woodies.

A large infestation of mullein being sprayed after clearing but before planting in the East Basin. Heisley Lewison photo