Teasel (Dipsacus sp.) is classified as an invasive plant. It was originally brought to North America from Europe and has thrived here. Even though it is considered a noxious weed, this biennial’s form and flower are striking. The first year, Teasel produces a rosette of leaves. The second year the flowering stem can grow to a height of almost eight feet.
Teasel is unique in the way in which it blooms. Flowers first form in a ring around the middle of the head. The ring of flowers grows in width over a few days, but since the flowers are relatively short lived, the center of the booming section may die off leaving two rings, one growing towards the top and one towards the bottom. Several long, leaf-like bracts branch out from the base of the flower and curve upward around the head.
Historically, Teasel’s seed head was used in the textile industry to raise the nap on woolen cloth. Although it is invasive and does crowd out native plants, Teasel redeems itself somewhat by providing insects with nectar and birds with a multitude of seeds (2,000 – 3,000/head). (Photo: Painted Lady (Vanessa cardui) on Teasel)