Plant Species: Helianthella uniflora, false sunflower
Phylum: Magnoliophyta -- flowering plants
Class: Magnoliopsida -- dicotyledons
Family: Asteraceae (Compositae) -- sunflower
Variety: the Palouse phase is var. douglasii
Common Name: false sunflower, Rocky Mountain helianthella, oneflower helianthella, Douglas’ helianthella, little sunflower.
Species Code: HEUND
Origin: The species is native to shrub-steppe to open forest of western North America from southern British Columbia to Oregon, Nevada, New Mexico and north to Montana. The Palouse phase, var. douglasii, has a more limited range in southern British Columbia, Washington, Oregon, and Idaho.
Form: forb, perennial from a taproot or caudex; stems clustered, 20-100 cm tall, erect to ascending, mostly simple, harshly puberulent to hirsute overall (sometimes glabrous below).
Longevity: medium lifespan
Habitat Type: prairie, shrub thickets, open forest
Wetland Indicator Status: FACU+
Leaves: basal leaves drying early; lower and middle cauline leaves opposite, scabrous, lanceolate to elliptic, 3-veined, up to 15 cm long.
Mature height: 20-30 inches
Flowers: heads usually terminal and solitary, involucre 12-15 mm tall, bracts lance-linear, subequal, acuminate to obtuse, hirsute-ciliate, margins hairy; ray flowers usually about 13, yellow, 20-30 mm long; disc usually 1.5-2 cm wide, disc flowers yellow, 5-6 mm long.
Flower color: yellow
Bloom: May, June, July
Bloom starts on: late May
Bloom ends on: mid June, sometimes extending into July in more protected areas
Fruit: achene, 6-7 mm long, compressed, wing-margined, finely appressed-hirsute, dark grayish-brown; pappus consisting of 2 unequal awns 3.5-4 mm long.
H. douglasii in Piper & Beattie 1914.
41,087 seeds/lb (USDA NRCS Pullman PMC 2005).
52,560-72,300 seeds/lb (Hassell et al 1996).
Reproduces sexually by seed.
Perennating organ is a caudex.
n=15 (Hitchcock et al 1969, Flora of North America Editorial Committee 1993).
Disc flowers are perfect, ray flowers are neutral.
Fruit is an achene.
Sun requirement: full sun to partial shade
Soil moisture: xeric to mesic
Precipitation: 10-35 inches for the species (USDA NRCS PLANTS Database 2009).
Sowing time: fall
Transplant time: spring
Stratification: cold moist
Seed yield: high
Seed harvest: mid July
Seed first harvest: third season
Seed cleaning: easy
Planting duration: long
Seed insect problem: yes
Seed shatter: low
Seed size: large
Seed harvest date: mid July
Seed comments: flowering is indeterminate, seed ripens over a period of 3-4 weeks.
Key words: upland forb
Alternate Species: douglasii
2 protocols in the Native Plant Network
University of Utah
Pullman WA Plant Materials Center
Other Propagation Information:
Germinates at a constant temperature 15oC or alternating temperatures of 20/30oC in light or dark (Chirco & Turner 1986).
120 days of cold moist stratification with light resulted in highest germination. Germinates at low temperatures during stratification (Nauman 2002).
No pretreatment required (Link 1993).
Germination was only 4-8% under several light and temperature combinations without cold moist stratification (Maguire & Overland 1959).
Reproduces sexually by seed.
Notes: Helianthella uniflora blooms about the time arrowleaf balsamroot is finishing up, so it prolongs the “yellow sunflower” season. Flowers in its second or third season, so it is quicker than balsamroot as well. Seed germination is variable, sometimes good, sometimes very low. It is tap-rooted, so does not take kindly to being transplanted. Flowers in June. Common names include false sunflower, Rocky Mountain helianthella, oneflower helianthella, Douglas’ helianthella, little sunflower (Skinner et al 2005).
Chirco, Ellen, and Terry Turner. 1986. Species Without AOSA Testing Procedures. The Newsletter of the Association of Official Seed Analysts 60(2):2-66.
Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 7+ vols. New York and Oxford. Oxford University Press. Online at http://www.fna.org/FNA/
Hassell, Wendell, W. Rocky Beavers, Steve Ouellette, and Thomas Mitchell. 1996. Seeding Rate Statistics for Native and Introduced Species. US Dept of Interior and USDA, NRCS. Denver, CO.
Hitchcock, C. Leo, Arthur Cronquist, Marion Ownbey, and J.W. Thompson. 1969. Vascular Plants of the Pacific Northwest. University of Washington Press. Seattle, WA. 5 vol.
Link, Ellen (ed.). 1993. Native Plant Propagation Techniques for National Parks Interim Guide. USDA, NRCS, Rose Lake Plant Materials Center. East Lansing, MI.
Maguire, James D., and Alvin Overland. 1959. Laboratory Germination of Seeds of Weedy and Native Plants. Washington State Agricultural Experiment Station Circular 349, Pullman, WA. 15 p.
Nauman, C. 2002. Germination of 12 Palouse Prairie Forbs After Stratification Under Light and Dark Treatments. M.S. Thesis, University of Idaho, Moscow ID.
Piper, C.V., and R.K. Beattie. 1914. The Flora of Southeastern Washington and Adjacent Idaho. Lancaster, PA: Press of the New Era Printing Company. 296 pp.
Skinner, David M., Paul Warnick, Bill French, and Mary Fauci. 2005. Characteristics and Uses of Native Palouse Forbs in Landscaping. Palouse Prairie Foundation. Online at http://www.wsu.edu/pmc_nrcs/Docs/Forbs_for_Landscaping.pdf
USDA NRCS, Pullman Plant Materials Center. 2005. Seed Weights of Some Palouse Native Species. Pullman Plant Materials Center, Pullman, Washington. Online at http://www.wsu.edu/~pmc_nrcs/Docs/Seed_Weights_Palouse_Native_Species.pdf
USDA NRCS. 2009. The PLANTS Database (http://plants.usda.gov, 5 August 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.