Taxon  Report   6751    
Polygonum douglasii  Greene  ssp. johnstonii  (Munz) J. C. Hickman  
(no longer an active name)
Johnston's knotweed,  Knotweed
Polygonum douglasii ssp. johnstonii, a dicot, is an annual herb that is native to California, is also found outside of California, but is confined to western North America.

Bloom Period
Genus: Polygonum
Parent: Polygonum douglasii
Wetlands: Occurs usually in non wetlands, occasionally in wetlands
Name Status:
Accepted by PLANTS

JEF other name:
Polygonum sawatchense ssp. sawatchense

Alternate Names:
PLANTS: Polygonum douglasii var. johnstonii
PLANTS: Polygonum sawatchense ssp. oblivium
PLANTS: Polygonum sawatchense
. . .
NOTE: Polygonum douglasii ssp. johnstonii is no longer an active name.
More information about  Polygonum douglasii ssp. johnstonii
Nursery availability from CNPLX
Commercial availability unknown.
Jepson eFlora


Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria. [web application]. 2019. Berkeley, California: The Calflora Database [a non-profit organization]. Available:   (Accessed: Dec 15, 2019).