Verbascum thapsus L.

Title: Verbascum thapsus L.

Scientific name:

Verbascum thapsus L.

Common name(s):

great mullein, velvet dock

Source & more images via ALA

Habitat: Temperate regions growing well on dry, disturbed, well drained sites often of low fertility and high pH, in areas with more than 500 mm annual rainfall and moderate summer temperatures (Parsons and Cuthbertson, 1992). It is a weed of roadsides, railway easements, poorer pastures, and unimproved indigenous grasslands (Parsons and Cuthbertson, 1992). Great mullein invades lowland grassland and grassy woodland, riparian vegetation, and alpine and subalpine vegetation (Carr et al., 1992).

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? "Seeds germinate in autumn and spring”. (Parsons and Cuthbertson, 1992, p. 587)

2. Establishment requirements? Establishes in open habitats and ecosystems e.g. areas of abandoned cultivation. (Parsons and Cuthbertson, 1992 p. 587)

3. How much disturbance is required? Invades undisturbed ecosystems (e.g. alpine and sub-alpine vegetation). (Carr et al., 1992)

GROWTH / COMPETITIVE

4. Life form? Erect biennial herb. Other. (Parsons and Cuthbertson, 1992 p. 586)

5. Allelopathic properties? “Allelopathic effects have been reported on wheat seedlings but this is not a practical problem because the plant is not a weed of cereal crops”. (Parsons and Cuthbertson, 1992 p. 588)

6. Tolerates herb pressure? “The rosettes, which cover a large area, are rarely eaten by livestock”. (Parsons and Cuthbertson, 1992 p. 587)

7. Normal growth rate? “It prefers disturbed habitats with little other vegetation”. “It is easily crowded out by grasses or other competing vegetation”. (Bassard et al, 2000 p. 322/23)

8. Stress tolerance to frost, drought, w/logg, sal. etc? Tolerant of frost (occurs in southern Tasmania); drought (occurs in central New South Wales and Western Australia). Occurs in ‘moist meadows and drainage’s’ in California. (Parsons and Cuthbertson, 1992;Bassard et al, 2000 p. 323)

REPRODUCTION

9. Reproductive system? “Reproducing by seed”. “Flowers are autogamous, that is they self-pollinate if cross-pollination does not occur’. (Parsons and Cuthbertson, 1992 p. 586/87)

10. Number of propagules produced? “Single plants produce 200 to 300 capsuled with 500 to 800 seeds per capsule. This seed production can be 100,000 to 240,000 seeds per plant”. (Bassard et al, 2000 p. 323)

11. Propagule longevity? “In Denmark, seeds recovered from soil samples claimed to be more than 650 years old were viable”. (Parsons and Cuthbertson, 1992 p. 587)

12. Reproductive period? “Most plants are biennial but occasionally they can be annual or short lived perennials”. (Parsons and Cuthbertson, 1992 p. 587)

13. Time to reproductive maturity? “Plants usually bolt, flowering stem, in the second year and have a single stem covered with over lapping; woolly leaves from base to inflorescence”. (Bassard et al, 2000 p. 322)

DISPERSAL

14. Number of mechanisms? “Seeds are not adapted to dispersal by wind or animals and usually fall to the ground." (Bassard et al, 2000 p. 322)

15. How far do they disperse? Field studies report that seeds will disperse as far as eleven metres, but 75% fall within one metre of the parent plant”. “Most seeds fall within 1.5 metres of the parent plant when it is moved by wind or large animals." (Parsons and Cuthbertson, 1992 p. 587)

Impact Assessment

RECREATION

1. Restrict human access? Erect biennial herb to 2.5 metres high. The population density of the invasion depends upon the level of disturbance of a site. In England, an infestation of 5.2 flowering plants per square metre was observed in coppiced woodland two years after they were cut (i.e. at the peak of the flowering cycle). Lesser infestations are more common. Dense infestations would be a nuisance to people. (Parsons and Cuthbertson, 2001; Hoshovsky, 1986)

2. Reduce tourism? It invades natural meadow and forest openings. In dense infestations, it may affect some recreational activities such as bushwalking. (Remaley, 1998)

3. Injurious to people? “The leaf hairs are said to irritate human skin. However, an admirable recent use is in gardens frequented by blind people where its velvet leaves are pleasing to the touch.” (Parsons and Cuthbertson, 2001)

4. Damage to cultural sites? The plants are quite noticeable and would impose a moderate negative visual effect on cultural sites. The root comprises a single stout deep taproot, which would not cause structural damage. (Parsons and Cuthbertson, 2001)

ABIOTIC

5. Impact flow? Terrestrial species. (Parsons and Cuthbertson, 2001)

6. Impact water quality? Terrestrial species. (Parsons and Cuthbertson, 2001)

7. Increase soil erosion? In Victoria V. thapsus is most often found as small dense patches on roadsides, railway easements, poorer pastures and unimproved native grasslands. Although the plant does not have an extensive root system, the vegetative cover would limit soil erosion from wind. (Parsons and Cuthbertson, 2001)

8. Reduce biomass? “Seedling growth rates were 4 – 7 times faster on bare soils [than on vegetated soils], producing 2000 times more biomass with the same period.” Its presence in poorer pasture and unimproved native grassland would increase biomass. (Hoshvosky, 1986)

9. Change fire regime? A dense, broad-leaved biennial herb, the dead plant matter may increase the fuel load producing a slight increase in the frequency of fire risk. (“The thick woolly leaves were popular insoles in footwear and were even used as temporary outer soles in hard times.”) (Parsons and Cuthbertson, 2001)

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC=Plains grassy woodlands (E); CMA=Glenelg Hopkins; Bioreg=Goldfields; VH CLIMATE potential. “Intolerant of shade…will grow in almost any open area.” Occurs in medium to large populations in Victoria. Major impact on grasses and shrubs. (Remaley, 1998; Carr et al, 1992)

10(b) Impact on medium value EVC? EVC=Riparian scrub (E); CMA=Glenelg Hopkins; Bioreg=Glenelg Plain; VH CLIMATE potential. Impact as in 10(a) above. (Remaley, 1998; Carr et al, 1992)

10(c) Impact on low value EVC? EVC=Rock outcrop shrubland (E); CMA=Glenelg Hopkins; Bioreg=Central Victorian Uplands; VH CLIMATE potential. Impact as in 10(a) above. (Remaley, 1998; Carr et al, 1992)

11. Impact on structure? “Once established, it grows more vigorously than many native herbs and shrubs, and its growth can overtake a site in fairly short order.” Dense infestations would have a major effect on grasses and forbs. (Remaley, 1998)

12. Effect on threatened flora?

FAUNA

13. Effect on threatened fauna?

14. Effect on non-threatened fauna? The rosettes are rarely eaten by livestock. Likely that native fauna also rarely use the plant as a source of food. The broad rosettes cover a large area thus reducing available fodder. (Parsons and Cuthbertson, 2001)

15. Benefits fauna? No documented benefits

16. Injurious to fauna? The leaf hairs are said to irritate the mucous membranes of animals’ mouths. Possible reason why animals rarely eat the plant? (Parsons and Cuthbertson, 2001)

PEST ANIMAL

17. Food source to pests? Not known as a food source to pest animals.

18. Provides harbor? Not known to provide harbor for pest animals.

AGRICULTURE

19. Impact yield? Animals rarely eat the rosettes, which cover a large area replacing a considerable amount of pasture. Potential to reduce carrying capacity. (Parsons and Cuthbertson, 2001)

20. Impact quality? As a biennial, it does not appear to be a problem in cropping situations. Animals rarely eat the rosettes. (Parsons and Cuthbertson, 2001)

21. Affect land values? The plant is easily controlled in pasture situations through pasture improvement. Occurrence of the plant in this situation is unlikely to affect land value. (Parsons and Cuthbertson, 2001)

22. Change land use? The plant is easily controlled in pasture situations through pasture improvement. Land use not greatly affected. (Parsons and Cuthbertson, 2001)

23. Increase harvest costs? Not a weed of cropping. (Parsons and Cuthbertson, 2001)

24. Disease host/vector? None evident.

Feedback:

Do you have additional information about this plant that will improve the quality of the assessment? If so, we would value your contribution.

Assessment ratings originally made by the Victorian Department of Primary Industries.

The entry of this assessment was made possible through the generous support of The Weed's Network.

Attachments:

velvet dock via ala.JPG
distribution_map (57).png

referenced by (2)

wra1038: Common Name - V (via velvet dock)wra1001: Common Name - G (via great mullein)

Article: wra1872 (permalink)
Categories: :wra:v, :wra:inv1, :wra:invmh, :wra:inv2, :wra:invml, :wra:inv3, :wra:invh, :wra:inv4, :wra:invl, :wra:inv5, :wra:inv6, :wra:inv7, :wra:inv8, :wra:inv9, :wra:inv10, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impml, :wra:imp2, :wra:imp3, :wra:imp4, :wra:imp5, :wra:impl, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:impmh, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:impm, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imph, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 12 October 2009; 11:54:29 AM AEDT

Author Name: Jessica Mackay
Author ID: mackayj