Common teasel (Dipsacus fullonum) - Early Detection Species

Many common teasel flowering heads.

 
 

Common teasel plants can grow to over seven feet tall. They have light purple flowers and their seed heads can persist into the winter. In Minnesota, common teasel is an early detection species as it is not widespread in the state. Common teasel is a prohibited noxious weed on the eradicate list so any plants found must be killed.

Description

Appearance

Common teasel grows as round grouping of leaves (rosette) near the ground for one or more years and then sends up a flowering stalk up to seven feet tall. Common teasel has cylinder shaped flower heads with many small, light purple flowers. The plant dies after setting seed. The stalks and seed heads remain upright and visible over the winter.

Leaves and Stem

Common teasel grows a rosette of leaves near the ground for one or more years. These rosette leaves are somewhat oval-shaped, have white hairs, scalloped edges, and no lobes. The rosette leaves can grow up to 12 inches long and two inches wide. When the plant is ready to flower it puts up a flowering stalk that can grow up to seven feet tall. The leaves on the flowering stalk have serrated edges. Small prickles line the middle of the underside of the leaf. Leaves can be up to 12 inches long. Leaves attach to the stem opposite to one another and form a cup along the stem where they connect. The cup may hold water. The stems are round and have many small prickles.

Flowers

Common teasel has a cylindrical flowering head. The flowering head contains many small, light purple, tubular flowers. There are stiff green bracts under the flowering head. These bracts are longer in length than the flowering head. Flowers bloom June through October.

Seeds

Common teasel stalks and the seed heads can remain upright throughout the winter. Each seed head can produce thousands of seeds.

Roots

Common teasel has a large taproot that can grow up to two feet long. Additionally, there are many fibrous roots.

Biology

Common teasel has a rosette of leaves for one or more years. It then sends up a tall flowering stalk. The plant dies after it has set seed. Plants grow best in full sun, but can live with some shade. Plants grow in a variety of habitats, including prairies, grasslands, pastures, road and railroad rights-of-way, and along waterways.

Origin and Spread

Common teasel is native to Europe. Teasels were brought to the United States as early as the 1700s for use as garden plants and their seed heads were used by the fabric industry. Common teasel seed heads have been used in the cut flower industry. Common teasel is found in the northeastern United States and in western states. Common teasel is an early detection species in Minnesota as it has a limited distribution in the state.

Refer to EDDMapS Distribution Maps for current distribution.

Don't be fooled by these look-alikes

  • Cutleaf teasel, Dipsacus laciniatus (invasive) – Cutleaf teasel has white flowers while common teasel has purple flowers. For cutleaf teasel, the bracts are shorter than the flowering head, while for common teasel the bracts under the flowering head are longer than the flowering head. Cutleaf teasel leaves are divided and lobed while common teasel leaves are not.
  • Bull thistle, Cirsium vulgare (invasive) or other non-native or native thistles – Thistle leaves are alternate (come off the stem one at a time, not opposite one another), the leaves do not form a cup, and leaves and stems can have long spines.
  • Cup plant, Silphium perfoliatum var. perfoliatum (native) – Cup plant leaves come together to form a cup like common teasel does, but cup plant has a square stem and has yellow sunflower-like flowers.
  • Queen Anne's lace, Daucus carota (invasive) – The seed heads of Queen Anne's lace curl up into a "bird's nest" formation that can look like dried teasel seed heads from a distance. Up close the Queen's Anne's lace seed head has visible thin stalks holding the seeds. Queen Anne's lace has delicate, fern-like leaves and when in flower it has white flowers clustered in a flat, umbrella-shaped formation.
 
Regulatory Classification

Common teasel is a Minnesota Department of Agriculture Prohibited Noxious Weed on the Eradicate List meaning that the above and belowground parts of the plant must be destroyed. Additionally no transportation, propagation, or sale is allowed.

Threat to Minnesota

Common teasel can form dense stands that outcompete native species in prairies, grasslands, pastures, road and railroad rights-of-way, and along waterways. This can reduce species diversity, wildlife habitat, and forage availability.

What you should do

One way that invasive plant seeds and fragments can spread is in soil. Sometimes plants are planted purposefully. You can prevent the spread of invasive plants.

PlayCleanGo: Stop Invasive Species in Your Tracks

  • REMOVE plants, animals & mud from boots, gear, pets & vehicle.
  • CLEAN your gear before entering & leaving the recreation site.
  • STAY on designated roads & trails.
  • PLANT non-invasive species.
Native Substitutes
 
Control Methods

Mechanical control can be done by pulling the plant by hand or with equipment such as a shovel. Plants have large taproots that should be removed to prevent regrowth. View the Minnesota Department of Agriculture's noxious weed disposal information for guidance on what to do with the pulled plants. Mowing frequently can reduce the size of plants and reduce flower and seed production. However, plants can resprout and flower on short stalks, so monitor to remove flowering plants by other means. Mowing does not kill plants and can result in spread of seeds.

Herbicide control can be done using systemic herbicides that are taken up by plants and move within the plant, which can kill leaves, stems, and roots. Apply glyphosate or triclopyr herbicides to the rosette stage of the teasel plants. Apply herbicides to the rosettes in the early summer (May to early July) or in the fall (mid-September to the end of October).

Reporting

Report new occurrences by submitting a report through EDDMapS Midwest, emailing Arrest The Pest, calling Arrest the Pest (1-888-545-6684), or contacting your local county agricultural inspector

Resources