Teasel flowers.

The enemy

Common Teasel (Dipsacus fullonum L.), better known as Fuller’s teasel, is a biennial plant that grows up to 6 feet tall. This invader is classified as a B Listed Noxious Weed in Baker County.

It is a tap-rooted plant which produces stout branched stems. This stem is striate-angled with several rows of downward turned prickles. The plant produces purple flowers in dense cone-shaped seed heads. Each flower is covered by spine-like bractlets.

The plant desires moist areas and can become a monoculture. The seeds are not spread by wind, but are a desirable food source for birds, which aids the spread of the plant.

The attack

This plant is widespread throughout North America after it was introduced from Europe as an ornamental. As it likes moist areas such as ponds, irrigation canals, and disturbed sites, it spreads very rapidly. In the fall the stems and fruiting heads are commonly silvered or gilded for winter bouquets.

Once established the plants become quite thick and leave behind a woody growth and is not foragable by animals.

The defense

As with many other plants, do not transport this plant for the sake of its beauty. Also with most biennials digging up small patches can be effective.

Once established, the use of Telar XP (1 ounce per acre), Escort XP (1 ounce per acre), or Opensight (3.3 ounces per acre) are most effective. Bear in mind that none of these products can be used over the top of water. The only biological available is native grasshoppers, but they will only strip the plant of its leaves, but by the time this occurs the plant has already produced next year’s seeds. Mechanical control is effective if one finds just a plant or two.