Common name: Threadleaf ragwort, Bush senecio, Creek senecio, Shrubby butterweed, Comb butterweed, Smooth threaleaf ragwort, Mono ragwort, Douglas ragwort, Douglas groundsel, Sand wash groundsel, Felty groundsel, Old man, Yerba cana, Squawweed, Cenicillo, Senecio douglasii
A small, fast-growing plant that is seen in dry, gravelly, sandy areas; Threadleaf ragwort plants bloom profusely with bright yellow flowers covering the plant. It grows to a height of 1-1.3 meters with a heavily branched stem that’s woody at the base and green towards the tips.
Leaves are greenish-white, thin, feather-like, and covered with white downy hair. They are pinnatifid or divided into narrow leaflets with large clefts in between.
Beautiful yellow flowers are raised above the level of the leaves on tall stalks, that branch to produce a cluster of flowers. These flowers have 8-14 distinct yellow petals and a large central tuft of yellow disk florets. These petals are horizontal initially, but later start curling outwards as the flowers age.
The disk florets of Threadleaf ragwort plant later produce tiny seeds that are about 3mm long with a tuft of hair that helps the seeds in wind dispersal. They are also dispersed by water and animals.
Threadleaf ragworts live for 3-6 years producing bushy clusters that can beautify your garden very quickly. In the wild, they can spread over large areas and wreak havoc to the ecosystem, since these plants cannot be eaten by animals. The alkaloids contained in the leaves can cause liver diseases in horses and cattle.
The name Senecio stands for senes or old man, because of the white tufts of hair on the seeds; and the name flaccidus means relaxed, referring to the droopy, nature of the stem and leaves.
There are 3 variants of Threadleaf ragwort plants, Senecio flaccidus var. douglasii or Douglas’ ragwort; Senecio flaccidus var. monoensis or Smoothleaf ragwort; and Senecio flaccidus var. flaccidus or Threadleaf ragwort varying from each other in their leave colors and structure.
Though the plant has some toxicity, it has been used to treat stomach disorders, kidney diseases, cuts, sores, acne, and skin diseases in traditional herbal medicine. The plant was used as a broom, and leaves were used as bug repellents.
Propagation is through seeds.
Image credits: Nicy Joseph