Whether it has been along a roadside, in a ditch, on a spoil pile, in a vacant lot, or invading a CRP field, we have all seen them. Common teasel, cutleaf teasel and fuller’s teasel are weeds that have taken over many parts of Northwest Ohio. The plant thrives in coarse, wet, heavy clay soils and recently disturbed areas. It takes over and creates a monoculture by covering the ground surface with its rosettes, blocking sunlight from reaching other plants while preventing seeds of desired species from making soil contact.

Teasel seeds have a remarkable ability to lay in a seed bank for extended periods of time while remaining viable, waiting for the current cover to disappear so they can sprout and dominate the area. Once sprouted, they spend a full year growing their rosette, which grows wide and tight to the soil surface. The second year of growth is often dedicated to growing a fibrous stalk from the middle of the rosette, this is referred to as “bolting”. This stalk can reach heights of 8 feet. Some plants remain as a rosette for several years before growing leaves big enough to absorb the appropriate amount of energy required to bolt. At the top of this stalk are the flowers, some plants having many, which typically bloom June through September. Each seed head can have over 800 seeds, and an individual plant produces over 3,000 seeds on average. After going to seed, the flower and stalk dies, dries up to a light brown, and can stay standing for several years creating an aesthetically unpleasant cover. Seeds are transported by animals, water, and improperly cleaned vehicles and equipment. The aggressive nature of this plant makes it a hassle for landowners who have ditches, riparian areas, spoil piles, wet lowlands, grassy uplands, or conservation covers. This weed does very well in our soil types, and out competes our desirable native species. Though it grows thick and some songbirds eat the seeds, teasel provides very low-quality cover and food for our wildlife.

The best way to manage teasel is to keep your problems small and localized. It is much easier to remove spots of teasel, versus a field of it. Once teasel becomes well established, it pollutes the seedbank with an ultra-durable seed that retains its viability for extended periods of time and can germinate at any time during the growing season. To effectively remove teasel from an area, an ongoing process of mowing, herbicide application and tillage is required. In the late winter or early spring, locate areas where teasel is growing. Use the dead flowers and stalks from the year before to help you find rosettes which will need to be treated with herbicide during the spring, preferably before May. Mowing prior to applying herbicide may be necessary to achieve adequate herbicide coverage. Be sure to properly clean equipment on site after mowing so you do not spread teasel seed to other areas of your property. A follow up mowing during the summer will cut teasel plants before they develop a flower and seed head. This will result in the plant using what’s left of its energy to regrow the stalk and will likely not develop a flower or seed head. Landowners with CRP contracts should follow NRCS mowing guidelines. After mowing in the summer, tilling will help disrupt the roots of established teasel plants, disturb the soil, and encourage teasel seeds in the seedbank to germinate. A second herbicide application during the fall, preferably October/November, will kill any rosettes that have sprouted during the summer after the mowing and discing operations. A successful fall herbicide treatment is the most effective step in ridding teasel. This process may need to be repeated over the span of another growing season for areas that have severe infestations. Replanting the area with a desired species seed mix is recommended to prevent teasel regrowth. It is wise to always be on the lookout for teasel rosettes and spot spray and mow when they are discovered. Teasel infestations can be overwhelming, but it is not impossible to rid this monster from your property. All that’s required is time and proper planning. If you are struggling with teasel on your property or have questions about how to manage this weed, please contact me. I’d be happy to help.