NOXIOUS WEED
CO

     It is commonly stated in wildflower photograph books and in professional floras, that Erodium cicutarium (Filaree) is a non-native plant. Further, it is classified by a number of states, including Colorado, as a noxious weed. However, Utah flora expert Stanley Welsh indicates that as far back as scientific collections of plants have been made in the United States, Erodium has been collected, making it plausible that it is native.

     The most eminent 19th century John Torrey indicated in 1852:
"This plant is widely spread over the western part of North America, from the Rocky Mountains to the Pacific, and is doubtless indigenous".
(From Torrey's description of plants collected by Stansbury, in the Appendix to Stansbury's Exploration and survey of the Valley of the Great Salt Lake of Utah)".

     James Lightner relates the following in his "SAN DIEGO COUNTY NATIVE PLANTS IN THE 1830s":

"Introduction of non-native plants permanently altered the region’s vegetation. Sacks of agricultural seed the Spanish imported contained impurities including common weeds; some plants considered weeds today may have been welcomed by the Spanish as Old-World native forage [32]. Analysis of adobe bricks from the late 1700s and early 1800s has revealed familiar weeds such as Erodium cicutarium (Filaree), Malva parviflora (Mallow), Hordeum murinum (Hare Barley), Medicago polymorpha (Bur-clover) and Melilotus (Sweetclover) [33]. Thomas Coulter wrote of seeing Medicago in California in 1832; Thomas Nuttall collected Erodium along the Oregon Trail in 1834 and Festuca myuros (Rat-tail Fescue) in San Diego in 1836."

Lightner is assuming that Erodium cicutarium is non-native. Perhaps his examples indicate that Erodium cicutarium is native.

Filaree is a very common plant of roadsides and fields, and it often carpets large areas with bright, tiny, pink flowers.  Fall rains sprout the seeds and the resulting basal rosette of finely cut leaves then lies dormant through the winter until spring warmth and moisture brings it into full leaf and flower  --  although warm late fall weather can also bring flowers.  Plants bloom profusely for many weeks in the spring and continue blooming to a lesser degree into the fall.  Flowers open with the morning sun, and depending on how hot the day is, they close early or late in the afternoon to reopen the next day. The deeply cleft, fern-like leaves and deep roots have a strong pungent smell that I enjoy as I walk across patches of the plant on my property.

Given little moisture, few Erodium cicutarium plants grow and they stay close to the ground. Given abundant moisture, Erodium cicutarium will produce numerous interlocking plants crowding out other vegetation and growing to over a foot tall and wide with stout branches, many leaves, and numerous flowers.

The long, narrow, pointed Heron/Stork/Crane's bill shaped seed pods give rise to the genus name, "Erodium", from the Greek for "Heron".  "Arium" is Latin for "similar to", in this case for the resemblance of the leaves of Filaree to those of the poisonous Water Hemlock, Cicuta douglasii.  (Conium maculatum now bears the common name of "Poison Hemlock".  Both Cicuta and Conium plants are extremely poisonous.)

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Erodium cicutarium