Big Tarweed / Center For Plant Conservation
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Plant Profile

Big Tarweed (Blepharizonia plumosa)

Photo Credit: ©2016 Neal Kramer
  • Global Rank: T2 - Imperiled
  • Legal Status: N/A
  • Family: Asteraceae
  • State: CA
  • Nature Serve ID: 130640
  • Lifeform: Forb/herb
  • Date Inducted in National Collection:

Blepharizonia plumosa, or the big tarweed, is an annual herb that is currently threatened by urbanization, residential development, and non-native plant growth. Little is known about B. plumosa but it blooms in clay soils from mid summer into the fall in valley grasslands across Contra Costa, Alameda, and Stanislaus counties. Its conservation status is under review but, for now, it is being identified as “apparently secure”.   

Where is Big Tarweed (Blepharizonia plumosa) located in the wild?


It prefers valley/foothill grasslands where it thrives on clay soil

States & Provinces:

Big Tarweed can be found in California

Which CPC Partners conserve Big Tarweed (Blepharizonia plumosa)?

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 1 accessions of Blepharizonia plumosa in orthodox seed collection. There are as many as 1008 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 08/05/2020
  • Seed Collection

Based on an August 2020 extract of the California Plant Rescue Database, California Botanic Garden has collected 1 seed accessions of Blepharizonia plumosa from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 20 maternal plants

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Taxon Blepharizonia plumosa
Authority (Kellogg) Greene
Family Asteraceae
CPC Number 8088
ITIS 36849
Duration Annual
Common Names Big Tarweed
Associated Scientific Names Blepharizonia plumosa | Blepharizonia plumosa var. plumosa | Calycadenia plumosa | Hemizonia plumosa | Hemizonia plumosa var. plumosa
State Rank
State State Rank
California S2
Ecological Relationships


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