Isatis tinctoria - L.
Dyer's Woad
Other Common Names: Dyer's woad
Taxonomic Status: Accepted
Related ITIS Name(s): Isatis tinctoria L. (TSN 23151)
Unique Identifier: ELEMENT_GLOBAL.2.138895
Element Code: PDBRA1K010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Mustard Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Capparales Brassicaceae Isatis
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Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Isatis tinctoria
Conservation Status

NatureServe Status

Global Status: GNR
Global Status Last Changed: 22Mar1994
Rounded Global Status: GNR - Not Yet Ranked
Nation: United States
National Status: NNA
Nation: Canada
National Status: NNA (12Oct2016)

U.S. & Canada State/Province Status
United States California (SNA), Colorado (SNA), District of Columbia (SNA), Idaho (SNA), Illinois (SNA), Montana (SNA), Nevada (SNA), New Jersey (SNA), Utah (SNA), Virginia (SNA), West Virginia (SNA), Wyoming (SNA)
Canada British Columbia (SNA), Newfoundland Island (SNA), Ontario (SNA), Quebec (SNA)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

U.S. States and Canadian Provinces
Color legend for Distribution Map
NOTE: The distribution shown may be incomplete, particularly for some rapidly spreading exotic species.

U.S. & Canada State/Province Distribution
United States CAexotic, COexotic, DCexotic, IDexotic, ILexotic, MTexotic, NJexotic, NVexotic, UTexotic, VAexotic, WVexotic, WYexotic
Canada BCexotic, NFexotic, ONexotic, QCexotic

Range Map
No map available.

Ecology & Life History Not yet assessed
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank)
Disclaimer: While I-Rank information is available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. Species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species with higher-than-average impact.

I-Rank: High/Low
Rounded I-Rank: Unknown
I-Rank Reasons Summary: Isatis tinctoria in the eastern U.S. appears to be spreading very slowly from an initial introduction point in Virginia as part of the dyeing industry. Isatis tinctoria in the western U.S. is an aggressive competitor in agricultural and natural areas. The rate of spread in the Intermountain West is high, and may allow for monocultures in areas with previously little vegetation. Methods of control are aided by early detection and prevention.
Subrank I - Ecological Impact: Medium/Insignificant
Subrank II - Current Distribution/Abundance: High/Medium
Subrank III - Trend in Distribution/Abundance: High/Medium
Subrank IV - Management Difficulty: High/Low
I-Rank Review Date: 16Sep2004
Evaluator: Fellows, M.
Native anywhere in the U.S?
Native Range: Southeastern Europe and western Asia (Gleason 1952) including southwestern Russia (CDFA 2004).

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Screening Questions

S-1. Established outside cultivation as a non-native? YES
Comments: (Kartesz 1999).

S-2. Present in conservation areas or other native species habitat? Yes
Comments: May invaded undisturbed sites including intermountain forests (CDFA 2004).

Subrank I - Ecological Impact: Medium/Insignificant

1. Impact on Ecosystem Processes and System-wide Parameters:Medium significance/Insignificant
Comments: No significant negative effects on ecosystem process reported.

2. Impact on Ecological Community Structure:Moderate significance
Comments: Often invades on dry rocky soils that do not have a herbaceous cover, thus creating a new canopy layer (CDFA 2004).

3. Impact on Ecological Community Composition:Medium/Low significance
Comments: May be temporarily allelopathic (rotting seed pods) at the seedling stage, giving it a competitive edge (NWCB 2003).

4. Impact on Individual Native Plant or Animal Species:Unknown
Comments: Toxic to livestock (NWCB 2003).

5. Conservation Significance of the Communities and Native Species Threatened:Medium/Low significance
Comments: May invaded undisturbed sites including intermountain forests (CDFA 2004).

Subrank II. Current Distribution and Abundance: High/Medium

6. Current Range Size in Nation:Medium/Low significance
Comments: Most occurrences are in the western US with a few scattered occurrences in IL, NJ, NY, VA, and WV (Kartesz 1999). Established in western VA, but only occassional elsewhere (Gleason 1952; NRCS 2004).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:High/Moderate significance
Comments: Eight of the 10 western states have placed Isatis tinctoria on the noxious species lists (Kartesz 1999). It is a serious weed only in the west (Prather et al. 2002).

8. Proportion of Nation's Biogeographic Units Invaded:Moderate significance
Comments: Inferred from current distribution (Kartesz 1999; NRCS 2004) and ecoregion boundaries (TNC 2001).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:Moderate significance
Comments: Roadsides, rangeland, agronomic crops (e.g. pastures, grain and alfalfa) and undisturbed natural areas (e.g. forest) in intermountain west region of the northwestern US (CDFA 2004).

Subrank III. Trend in Distribution and Abundance: High/Medium

10. Current Trend in Total Range within Nation:Moderate significance
Comments: Actively expanding range in intermountain west region of US (CDFA 2004). Rate of spread in Utah doubled from 1971 to 1981 (NWCB 2003).

11. Proportion of Potential Range Currently Occupied:Moderate significance
Comments: Given the ability of the species to invade natural, undisturbed areas, and the presence of additional habitats in the US that do not appear to be invaded currently, it is inferred that the proportion of potential range invaded is low.

12. Long-distance Dispersal Potential within Nation:High significance
Comments: Imported originally as a source of blue dye - spread for that purpose (Gleason 1952). Now spread long distances primarily as a contaminant or unintentionally as a result of human or animal activites (CDFA 2004). Seed available for sale on the Internet (9/04), by European companies.

13. Local Range Expansion or Change in Abundance:Unknown

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:High/Moderate significance
Comments: Can invade disturbed and undisturbed sites (CDFA 2004) from nearby seed sources on roadsides (NWCB 1999).

15. Similar Habitats Invaded Elsewhere:Moderate significance
Comments: Present in Canada (Kartesz 1999). The species is not often reported as non-native, as there are various anecdotal reports of Isatis tinctoria man-caused spread within its natural range in coastal areas and salt marshes (Internet 9/04).

16. Reproductive Characteristics:Moderate significance
Comments: Reproduction is by seed with an average of 383 1 seeded fruits per plant (CDFA 2004). No studies have examined the seedbank longevity, although there is evidence to support the theory that a seedbank is formed (NWCB 2003; CDFA 2004). As long as the root crown is not damaged, plants may resprout (CDFA 2004).

Subrank IV. General Management Difficulty: High/Low

17. General Management Difficulty:Moderate significance
Comments: Methods that destroy or remove the root crown such as hand pulling, herbicides or biological control agents are necessary for managment (CDFA 2004). Herbicides are most effective when applied at the rosette stage (Whitson et al. 1996).

18. Minimum Time Commitment:High/Low significance
Comments: Follow up treatments are required, may, in part, be due to a seed bank (CDFA 2004).

19. Impacts of Management on Native Species:Medium/Low significance
Comments: Most management techniques focus on spot treatments, which may cause some non-target damage.

20. Accessibility of Invaded Areas:High/Moderate significance
Comments: Some people consider this an ornamental species, or cultivate it for dye making (NWCB 2003). In addition, plants may grow on hard to reach or difficult terrain (NWCB 2003).

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • California Department of Food and Agricutlure (CDFA). 2004. Noxious Weed Data Sheet. Carduus genus. Available ONLINE: Accessed 2004.

  • Gleason, H.A. 1952. The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. 3 volumes. Hafner Press, New York. 1732 pp.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.

  • Prather, T. S., S. S. Robins, D. W. Morishita, L. W. Lass, R. H. Callihan, and T. W. Miller. 2002. Idaho's Noxious Weeds. University of Idaho Extension, Moscow. 76 pp.

  • The Nature Conservancy. 2001. Map: TNC Ecoregions of the United States. Modification of Bailey Ecoregions. Online . Accessed May 2003.

  • USDA, NRCS. 2004. The PLANTS Database, Version 3.5 ( . National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

  • Washington State Noxious Weed Control Board (NWCB). 2003. Written Findings of the State Noxious Weed Control Board. Available: (Accessed 2004).

  • Whitson, T.D. (ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 1996. Weeds of the West. 5th edition. The Western Society of Weed Science in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark, CA. 630 pp.

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