Plant Assessment Form

Verbascum thapsus

Common Names: woolly mullein; common mullein; lungwort; feltwort; torches; Jacob's staff; velvetplant; old man's flannel; miner's candle

Evaluated on: 26-Jul-04

List committee review date: 27/08/2004

Re-evaluation date:

Evaluator(s)

Carri Pirosko
California Department of Food and Agriculture, Noxious Weed Program
20235 Charlanne Drive, Redding, CA 96002
(530) 545-9119
cpirosko@cdfa.ca.gov
Joseph M. DiTomaso
University of California
Weed Science Program, Robbins Hall, Davis, CA 95616
530-754-8715
ditomaso@vegmail.ucdavis.edu

List commitee members

Joe DiTomaso
John Randall
Jake Sigg
Cynthia Roye
Peter Warner
Alison Stanton

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 3.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes D Reviewed Scientific Publication
Impact?
Four-part score DCUD Total Score
C
1.2 ?Impact on plant community C. Minor Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels U. Unknown Reviewed Scientific Publication
1.4 ?Impact on genetic integrity D. None Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Reviewed Scientific Publication
Invasiveness?
Total Points
12 Total Score B
2.2 ?Local rate of spread with no management B. Increases less rapidly Reviewed Scientific Publication
2.3 ?Recent trend in total area infested within state C. Stable Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal B. Moderate Reviewed Scientific Publication
2.6 ? Potential for natural long-distance dispersal C. Rare Reviewed Scientific Publication
2.7 ?Other regions invaded C. Already invaded Reviewed Scientific Publication
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread
Distribution?
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
C. Low Reviewed Scientific Publication

Table 3. Documentation

Scores are explained in the "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands".

Section 1: Impact
Question 1.1 Impact on abiotic ecosystem processes? D Reviewed Scientific Publication
Identify ecosystem processes impacted:

Not much in literature about abiotic impacts, only post-fire references found, but even those impacts were short-term, see reference below. Appears to temporarily disrupt the normal sequence of ecological succession in post-forest-fire situations: Has been observed to rapidly establish following forest fires in the western Sierra Nevada; high densities of rosettes appear to prevent reinvasion of native herbs and grasses in burned areas- but this is only transient and it eventurally gives away to shrub canopy.


Sources of information:

Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Question 1.2 Impact on plant community composition,
structure, and interactions?
C Reviewed Scientific Publication
Identify type of impact or alteration:

Usually only a problem in sparsely vegetated/bare ground areas; one reference to invading undisturbed area (meadow). Common mullein is not often a significant weed of most wildlands and natural areas, as it is easily crowded out by grasses or other competing vegetation.
It is a problem in sparsely vegetated soils of the eastern Sierra Nevada
Has invaded pristine meadows with undisturbed soils, displacing native herbs and grasses, in Mono Lake and Owens Valley.
Has been observed to rapidly establish following forest fires in the western Sierra Nevada; high densities of rosettes appear to prevent reinvasion of native herbs and grasses in burned areas- but eventurally give away to shrub canopy.
Since mullein forms very dense populations after fire, due to the poor dispersal of seeds from the parent plant, its presence may hinder the establishment of other species and thus the future development of the community.
Thought to serve as host for insects that are themselves economic pests, such as mullein leaf bug, a pest of apples and pears- crops species, no references to impacts to native plant species.


Sources of information:

Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press; Gobbi, M., J. Puntieri, and S. Calvelo, 1995. Post Fire Recovery and Invasion by Alien Plant Species in a south American Woodland-Steppe Ecotone. Plant Invasions- General Aspects and Special Problems, pp. 105-115, Academic Publishing, Amsterdam, The Netherlands.


Question 1.3 Impact on higher trophic levels? U Reviewed Scientific Publication
Identify type of impact or alteration:

No impacts to higher trophic levels noted in literature (Other than references to mullein serving as a host for insects harmful to crops- but crops are not considered higher trophic levels).


Sources of information:

Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

No references in literature to impacts on genetic integrity and no native Verbascum species in California.


Sources of information:

Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
B Reviewed Scientific Publication
Describe role of disturbance:

Mullein is highly associated with disturbance, only one cited reference to invasion into a pristine meadow, see reference below. Mullein is most commonly found as an early colonizer of abandoned fields or along field edges, or roadsides
One of the first species to invade roadsides that have been treated with soil-active herbicides
Has invaded pristine meadows with undisturbed soils, displacing native herbs and grasses, in Mono Lake and Owens Valley.


Sources of information:

Mitich, L.W., 1989. Intriguing World of Weeds, Common Mullein- the roadside torch parade. Weed Technology Vol. 3:704-705. Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Question 2.2 Local rate of spread with no management? B Reviewed Scientific Publication
Describe rate of spread:

Rate of spread is rather slow, as most seed do not move far from parent plant; increases, but less rapidly to stable. Seed dispersal is passive and generally limited to ca. 4 meters


Sources of information:

Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Question 2.3 Recent trend in total area infested within state? C Observational
Describe trend:

Personal observation, have seen more and more along roadsides, roadside pull-outs, and abandoned areas in the northeast part of the state. However, it is an early colonizer, often replace by something else- over time, except in bare ground areas.
Increasing in some areas, but in general probably stable statewide. Mullein is most commonly found as an early colonizer of abandoned fields or along field edges, or roadsides
One of the first species to invade roadsides that have been treated with soil-active herbicides
Movement of soil for highway and building construction assists in dispersal; as well as gardening


Sources of information:

Mitich, L.W., 1989. Intriguing World of Weeds, Common Mullein- the roadside torch parade. Weed Technology Vol. 3:704-705.
Personal observation in NE California, C. Pirosko, also J.M. DiTomaso


Question 2.4 Innate reproductive potential? A Reviewed Scientific Publication
Describe key reproductive characteristics:

reproduces by seed only, prolific seed producer! Field studies show that a single plant produces 200-300 capsules with 500-800 seeds per capsule; thus seed production can be 100,000 - 240,000 seeds per plant.
See notes with Worksheet A


Sources of information:

Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Question 2.5 Potential for human-caused dispersal? B Reviewed Scientific Publication
Identify dispersal mechanisms:

There are numerous opportunities for dispersal to new areas, through constant and widespread roadside construction, but not really into wildland areas. The vast majority of seed do not disperse long distances. Movement of soil for highway and building construction assists in dispersal


Sources of information:

Mitich, L.W., 1989. Intriguing World of Weeds, Common Mullein- the roadside torch parade. Weed Technology Vol. 3:704-705. Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Question 2.6 Potential for natural long-distance dispersal? C Reviewed Scientific Publication
Identify dispersal mechanisms:

Very little potential for natural long-distance dispersal, seed on animals is always a possibility though. Seeds have no specialized structures for long-distance dispersal by wind or animals
Seed dispersal is passive and generally limited to ca. 4 meters


Sources of information:

Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Question 2.7 Other regions invaded? C Reviewed Scientific Publication
Identify other regions:

Found in all 48 contiguous states and in Hawaii, in Canada it is reported to grow abundantly in soils with a pH range 6.5-7.8 and is found from sea level to 8,000 feet elevation
Found throughout the U.S. and in southern Canada, in the British Isles, and throughout Europe, as far north as Norway and as far east as the Western Himalayas
Naturalized through N. America, Chile, Hawaii, Australia, and New Zealand Mullein has already invaded habitat types in California, similar to elsewhere across the globe


Sources of information:

Mitich, L.W., 1989. Intriguing World of Weeds, Common Mullein- the roadside torch parade. Weed Technology Vol. 3:704-705. Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A

Occurs throughout California, but is particularly abundant in dry valleys on the eastern side of the Sierra Nevada. High population densities have been observed in moist meadows and creek drainages near Mono Lake and Owens Valley. It prefers disturbed habitats with little other vegetation, especially on dry, gravelly soils.
Common along roadsides, right-of-ways, and river banks and in forest cuts, meadows, pastures, and waste areas.
Disturbed, open sites: roadsides, abandoned fields, abandoned homesteads, industrial sites
Riparian corridors, shrublands, juniper woodlands, scrub oak savannahs, California sagebrush associations


Sources of information:

Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, 2000. Invasive Plants of California's Wildlands, University of California Press.


Question 3.2 Distribution/Peak frequency? C Reviewed Scientific Publication
Describe distribution:

See references in 3.1 and Worksheet C See references in 3.1 and Worksheet C


Sources of information:

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes
Dense infestations produce >1,000 viable seed per square meter Yes
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually Yes
Seeds remain viable in soil for three or more years Yes
Viable seed produced with both self-pollination and cross-pollination Yes
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes No
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned No
Total points: 8
Total unknowns: 0
Total score: A?

Related traits:

A population usually has both first year rosettes and 2nd year bolting plants, thus populations seed every year; seed can have a long dormancy, requiring light and enhanced by cold temps, can retain high levels of viability for at least 17 years

Worksheet B - Arizona Ecological Types is not included here

Worksheet C - California Ecological Types

(sensu Holland 1986)
Major Ecological Types Minor Ecological Types Code?
Marine Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirs
Aquatic Systemsrivers, streams, canals
estuaries
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrub
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieD, < 5%
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seepD, < 5%
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forestD, < 5%
riparian woodlandD, < 5%
riparian scrub (incl.desert washes)C, 5% - 20%
Woodlandcismontane woodlandD, < 5%
piñon and juniper woodlandC, 5% - 20%
Sonoran thorn woodland
Forestbroadleaved upland forestD, < 5%
North Coast coniferous forest
closed cone coniferous forest
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): A
Distribution (highest score): C

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Central West
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Southwest
  • Modoc Plateau
  • Sierra Nevada East
  • Desert Province
  • Mojave Desert
  • Sonoran Desert