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Plant Profile

Peacock Larkspur (Delphinium pavonaceum)

Delphinium pavonaceum in bloom in situ in Oregon.

Photo Credit: Dan van den Broek
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: N/A
  • Family: Ranunculaceae
  • State: OR
  • Nature Serve ID: 146865
  • Lifeform: Forb/herb
  • Date Inducted in National Collection: 03/05/1993
Description:

Between 13,000 and 15,000 years ago, a series of huge ice dams formed in Montana, backing up very large lakes. The dams occasionally broke unleashing immense amounts of water that tore through Oregon and Washington at tremendous speeds (nearing 90 miles per hour (144 kph)). The resulting Missoula floods caused intense destruction, altered stream courses, and destroyed established existing vegetation, but also brought in fresh deposits of silt and gravel. Scientists think that the Peacock larkspur (Delphinium pavonaceum), probably arose during this time, from either a mutation or from hybridization, and became established in sites disturbed by this flood. The peacock larkspur is found only in the Willamette Valley of Oregon. Presently, the natural vegetation of the Willamette Valley is experiencing a threat not altogether different in magnitude from the Missoula Floods - human development. Since nearly all grassland habitat has been converted to agricultural and residential use, the peacock larkspur is now found almost exclusively along fencerows and ditches where small patches of habitat have escaped complete destruction. But even the few populations that have escaped development are at risk. The white-flowered peacock larkspur appears to hybridize with a purple-flowered species and it is in danger of diluting the peacock larkspur's genetics until it is no longer is a distinct species (Goodrich 1983).

Where is Peacock Larkspur (Delphinium pavonaceum) located in the wild?

Habitat:

Well drained areas of native prairie, especially roadsides that have escaped development (Meinke 1982). In floodplains, can be found on high mound areas that are better drained than surrounding prairie (Finley and Ingersoll 1994). Associated species include Potentilla gracilis, Deschampsia cespitosa, Poa pratensis, and Rosa spp. (Meinke 1982) and Spiraea douglasii (Finley and Ingersoll 1994). Along roadsides with Rubus spp., Rhus diversiloba, and Fraxinus latifolia (Finley and Ingersoll 1994).

Distribution:

The Willamette Valley of Oregon.

States & Provinces:

Peacock Larkspur can be found in Oregon

Which CPC Partners conserve Peacock Larkspur (Delphinium pavonaceum)?

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

  • 09/08/2020
  • Seed Collection Orthodox Seed Banking

Seeds from 5 sites stored at Rae Selling Berry Seed Bank and Conservation Program.

  • 09/08/2020
  • Reproductive Research

Comprehensive study of systematics, morphology, distribution, ecology, and reproductive dynamics (Goodrich 1983). A 1994 field survey found that populations varied in size from 3 to more than 2000 flowering individuals. Roadside plants appeared to be immanently threatened by the invasion of reed canary grass (Phalaris arundinacea) and other roadside weeds. Other sites appeared to be threatened by encroaching canopy of trees and tall shrubs (Finley and Ingersoll 1994) Observations indicated no evidence of hybridization with blue-flowered Delphinium menziesii where the two flowers co-occurred (Finley and Ingersoll 1994). Comparison between plants found in burned and unburned areas of a Research Natural Area (RNA) found that abundance, growth and reproduction was higher in burned areas. These observations are consistent with the hypothesis that frequent burning enhances growth and reproduction, but researchers note other factors that could contribute to the difference including a moisture gradient between the two areas (Finley and Ingersoll 1994).

  • 09/08/2020
  • Propagation Research

Germination trials at The Berry Botanic Garden indicate that a long period of cold stratification is required for germination. No seeds germinated when subjected to 8 weeks of cold stratification. When seeds were subjected to 12 weeks of cold stratification followed by constant 68F (20C) temperatures, 33% of the seeds germinated. With 12 weeks of cold stratification followed by alternating 50/68F (10/20C) temperatures, 14% of the seeds germinated (BBG file)

  • 09/08/2020
  • Genetic Research

Turner (1992) described the mitotic and meiotic chromosomes of four Oregon Delphinium species: D. trolliifolium, D. menziesii, D. pavonaceum and D. leucophaeum, for taxonomic comparison. Initial examination of chloroplast genetic variation within a population of Delphinium pavonaceum known to have color and chloroplast variation did not reveal the source of color variation or give insight to any past hybridization event (Mazer 2000).

Edward Guerrant, Ph.D.
  • 01/01/2010

Urban expansion (Meinke 1982) Agricultural development (Meinke 1982) Herbicides (both agricultural and roadside) (Meinke 1982) Woody plant encroachment (Finley and Ingersoll 1994) Hybridization with a purple-flowered Delphinium (Karoly personal c

Edward Guerrant, Ph.D.
  • 01/01/2010

Historically, 35 occurrences known in Benton, Polk, Marion, Multnomah, and Clackamas counties. Only 18 occurrences have been seen since 1980. Population sizes range from as little as 1 to as many as 2000. Most have between 10 and 100 (ONHDB 2000).

Edward Guerrant, Ph.D.
  • 01/01/2010

Comprehensive study of systematics, morphology, distribution, ecology, and reproductive dynamics (Goodrich 1983). A 1994 field survey found that populations varied in size from 3 to more than 2000 flowering individuals. Roadside plants appeared to be immanently threatened by the invasion of reed canary grass (Phalaris arundinacea) and other roadside weeds. Other sites appeared to be threatened by encroaching canopy of trees and tall shrubs (Finley and Ingersoll 1994) Observations indicated no evidence of hybridization with blue-flowered Delphinium menziesii where the two flowers co-occurred (Finley and Ingersoll 1994). Comparison between plants found in burned and unburned areas of a Research Natural Area (RNA) found that abundance, growth and reproduction was higher in burned areas. These observations are consistent with the hypothesis that frequent burning enhances growth and reproduction, but researchers note other factors that could contribute to the difference including a moisture gradient between the two areas (Finley and Ingersoll 1994). Turner (1992) described the mitotic and meiotic chromosomes of four Oregon Delphinium species: D. trolliifolium, D. menziesii, D. pavonaceum and D. leucophaeum, for taxonomic comparison. Initial examination of chloroplast genetic variation within a population of Delphinium pavonaceum known to have color and chloroplast variation did not reveal the source of color variation or give insight to any past hybridization event (Mazer 2000). Germination trials at The Berry Botanic Garden indicate that a long period of cold stratification is required for germination. No seeds germinated when subjected to 8 weeks of cold stratification. When seeds were subjected to 12 weeks of cold stratification followed by constant 68F (20C) temperatures, 33% of the seeds germinated. With 12 weeks of cold stratification followed by alternating 50/68F (10/20C) temperatures, 14% of the seeds germinated (BBG file)

Edward Guerrant, Ph.D.
  • 01/01/2010

Seeds from 5 sites stored at The Berry Botanic Garden.

Edward Guerrant, Ph.D.
  • 01/01/2010

Maintain habitat in an undisturbed state (Meinke 1982). Mowing, hand removal of shrubs and trees, and prescribed burning to prevent encroaching shrubs and weedy species. Concurrent monitoring in order to assess the effectiveness of such techniques (Finley and Ingersoll 1994). Evaluate methods of controlling Phalaris arundinacea (reed canary grass) and implement effective measures (Finley and Ingersoll 1994).

Edward Guerrant, Ph.D.
  • 01/01/2010

Collect and store seeds from known populations. Determine optimum germination requirements. Determine propagation and reintroduction protocols.

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Nomenclature
Taxon Delphinium pavonaceum
Authority Ewan
Family Ranunculaceae
CPC Number 1387
ITIS 821198
USDA DEPA4
Duration Perennial
Common Names peacock larkspur
Associated Scientific Names Delphinium pavonaceum | Delphinium X pavonaceum
Distribution The Willamette Valley of Oregon.
State Rank
State State Rank
Oregon SNA
Ecological Relationships

Photos
Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Bumble bees Bumblebees Confirmed Pollinator Link

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