Quick Facts

Quick facts

• Great Mullein (Verbascum thapsus) is a short lived (annual or biennial) herb growing 1–3 m high, with a large basal rosette of leaves, and generally a single large flowering stem, with many 5-petaled yellow flowers to 3 cm  across.
• It is a weed of disturbed sites but also occurs in open habitats such as forest margins and creek beds, and open grasslands.
• It is not generally grazed and can replace a large amount of pasture, potentially reducing carrying capacity.
• It can invade undisturbed ecosystems and has potential to significantly alter plant community structure in these areas.
• Great Mullein is easily removed by pulling or grubbing, but care should be taken to remove and destroy all fruit and seeds. 
• Herbicides are also useful if applied at the rosette stage before flowering.

What Does It Look Like?

What is it?

Great Mullein (Verbascum thapsus) is a large, annual or biennial herb growing 1–3 m in height with a deep, stout taproot. It initially grows as a basal rosette of leaves spreading on the ground, but becomes very upright as it grows, bearing the flowering stem. The stems and leaves are densely covered with soft hairs. The leaves are alternately arranged along the stem, grey-green in colour, and covered with short, matted, stellate (star-shaped) hairs without glands. The basal rosette leaves can be from 8 cm up to 50 cm long, and the stem leaves to 30 cm long, with lower leaves tapering at the base into a petiole (leaf-stalk), with the upper leaves tapering at the base to form 'wings' down the stems without a leaf-stalk. Leaves reduce in size towards the top of the plant. The leaves are obovate (shaped like a section through the long axis of an egg and attached by the thinner end) or oval (elliptical), and the upper leaves are generally more elongated than the lower ones. Leaves are prominently veined on the lower surface, and have entire (smooth) or crenulate (finely toothed) margins. 

The pale yellow-ivory to yellow flowers are densely clustered and are produced on a long spike-like raceme, 20–100 cm long, at the tops of the stems. Great Mullein usually has a single upright main flowering stem, but occasionally smaller flowering stems grow from the upper leaf axils. Flowers are borne on very short stalks 0.1-0.5 cm, and arranged in groups of 1–7 in each bract axil, bracts 12–18 mm long. Sepals (the outer whorl of non-fertile parts surrounding the fertile organs, usually green) are 6–12 mm long. Flowers are 5-petaled, 1.2–3 cm across, pubescent (covered with short, soft, erect hairs) outside with numerous glandular dots, with 5 stamens of different lengths, from10–15 mm long.

The fruits are rounded or egg-shaped capsules, 7-10 mm long and 3–6 mm wide, covered with tiny hairs, and contain up to 600 tiny reddish-brown, rod-shaped, pitted seeds less than 1 mm long, 5 or 6 sided, rod-shaped with one pointed end. (Barker 1986; Parsons & Cuthbertson 2001; Navie 2004; Vic Flora 2016).

For further information and assistance with identification of Great Mullein contact the herbarium in your state or territory.

Flower colour

Yellow

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Great Mullein occurs in temperate, subtropical and some semi-arid regions, and often grows well in dry, disturbed and well drained or sandy sites of low fertility (Parsons & Cuthbertson 2001; Navie 2004). It grows best in open habitats, and is shade intolerant (Victorian Resources Online 2007). It is typically a weed of unimproved pastures or sandy pastures and disturbed sites such as roadsides, old settlements, rocky outcrops, and waste areas (Navie 2004; Hussey et al. 1997), but also occurs in dry or stony creek beds and forest margins (Robbins et al. 1970; Navie 2004).

Are there similar species?

Great Mullein (Verbascum thapsus) is similar to several other Verbascum species found in Australia including, Twiggy Mullein (V. virgatum), Moth Mullein (V. blattaria), and Cretan Mullein (V. creticum). 

Great Mullein (V. thapsus) has grey-green stems and leaves that are densely covered with small, star-shaped hairs. The leaves are entire or finely toothed (crenulate). The flowering stem is robust and generally not branched. The flowers are densely packed along the flowering stem. 

Twiggy Mullein (V. virgatum) has darker stems and leaves that are sparsely covered in short, simple glandular hairs, not stellate (or star-shaped) as in Great Mullein). The leaves of this species are coarsely toothed (crenate), while those of Great Mullein are entire or finely toothed (crenulated). The flowering stems are sometimes branched, and are not as robust as those of Great Mullein. The flowers are loosely arranged and more widely spaced along the flowering stem, compared to those of Great Mullein, flowers are on shorter flower-stalks (i.e. pedicels) 1–2 mm long, and the immature fruit are sparsely covered in sticky (i.e. glandular) hairs.

Moth Mullein (V. blattaria) has darker green and hairless (glabrous) or sparsely hairy stems and leaves. Its leaves are deeply toothed or lobed compared to those of Great Mullein, which are entire or finely toothed (crenulated). The flowers of Moth Mullein are loosely arranged along the stem and are borne on relatively long flower-stalks (10-25 mm), compared to those of Great Mullein (1–5 mm).

Cretan Mullein (V. creticum) has darker green and moderately hairy stems and leaves. Its leaves are somewhat wrinkled in appearance (rugulose) compared to those of Great Mullein. Cretan Mullein has only 4 stamens (male parts of the flower) per flower, compared to 5 in Great Mullein, and it has toothed bracts (modified leaves below the flower) and sepals, while those of Great Mullein are entire (not toothed) (Barker 1986; Navie 2004).

Why Is It A Weed?

What are its impacts?

Great Mullein is capable of spreading very quickly and rosettes covering a large area.

Agriculture: Great Mullein is generally not grazed and its survival is favoured by the removal of competitive species. It can therefore replace a considerable amount of pasture, potentially reducing carrying capacity (Parsons & Cuthbertson 2001; Victorian Resources Online 2007). This plant is poisonous to stock, but the risk of this occurring is minimal as the animals do not tend to feed on it as the dense hairs on the plant irritate the skin and mouths of stock. Studies of Great Mullein have reported the production of anti-germination and root-growth inhibiting compounds that affect the seeds of Barley (Hordeum vulgare). This is not thought to be of any significance in Australia as Great Mullein is not a weed of cereal crops (Pardo et al. 1998; Parsons & Cuthbertson 2001).

Native ecosystems: Great Mullein can invade undisturbed ecosystems, generally open habitats such as grasslands, and therefore has the potential to displace native herb and grass species. High density populations have the potential to significantly alter plant community structure (Victoria Resources Online 2007). While not known to cause major problems of this sort in Australia, in other areas (e.g. North America) Great Mullein adapts easily to a wide variety of natural habitats, grows vigorously to out-compete native species, and can threaten the regeneration of degraded native areas (Remaley 1998; Starr et al. 2003).

How does it spread?

Great Mullein is spread by seed only. It is estimated that it can produce between 100,000 to 240,000 seeds per plant, which may be viable for up to 100 years (Remaley 1998; Bassard et al  2000 ). In Denmark, seeds from soil samples claimed to be more than 650 year old were found to be viable (Parsons & Cuthbertson 2001). As seeds are very small, they readily contaminate soil or agricultural produce, and can be dispersed by wind, water or animals (Parsons & Cuthbertson 2001; Navie 2004). Most seeds, however, fall close to the parent plant (Remaley 1998).

What is its history in Australia?

Great Mullein was introduced as a garden plant, and was listed in Tasmanian and Victorian nursery catalogues in 1845 and 1855, respectively. It was also grown in the Hobart and Adelaide Botanic Gardens in the 1850s, and was considered naturalised in Victoria by 1887 (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Non-chemical control: Great Mullein is easy to remove manually, especially the seedlings, by pulling or grubbing, and removing as much of the taproot as possible (Remaley 1998; Parsons & Cuthbertson 2001). Removal of plants by hand or garden implement should be conducted prior to flowering (Remaley 1998). As this species produces abundant seed, if flowering has occurred, care should be taken to remove, bag and dispose of all flowering structures (Remaley 1998). Care should also be taken with pulling, as the loosening of the soil can stimulate seed germination in this species (Remaley 1998). Larger patches may be cultivated, but subsequent pulling may be required to remove seedlings in following seasons (Parsons & Cuthbertson 2001).

Chemical control: Herbicides can be useful if applied to the leaves at the rosette stage, before flowering when actively growing in autumn, winter and spring  (Remaley 1998; Parsons & Cuthbertson 2001).

Biological control: Great Mullein is not currently a Target for Biological Control in Australia. Two insect species, the European Curculionid Weevil (Gymnaetron tetrum) and the Mullein Moth (Cucullia verbasci) have been tested in the United States and have possible biological control implications for Great Mullein (Remaley 1998).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Seeds of Great Mullein germinate in autumn and spring, and plants form a rosette of leaves and large taproot during the first summer. Vegetative growth continues, where the rosette and roots increase in size, until temperatures decline in autumn and winter. During the second spring and summer, plants reach maturity and quickly flower, produce seed, and die (Remaley 1998). It is able to self pollinate if cross pollination does not occur (Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, QLD, SA, TAS, VIC, WA

What areas within states and territories is it found?

Great Mullein is widespread in Australia, occurring in all states with the exception of the Northern Territory. It is generally restricted to temperate regions with an annual rainfall of more than 500 mm and moderate summer temperatures. It occurs frequently in south-western Western Australia, in South Australia on the the Fleurieu Peninsula and the south-east of South Australia, and it is widespread throughout much of Victoria, Tasmania, and eastern New South Wales (Parsons & Cuthbertson 2001; Navie 2004). It is recorded from Queensland, but is not common in this state (Navie 2004). Great Mullein generally occurs as small dense patches, but can form extensive monotypic populations (Parsons & Cuthbertson 2001).

Where does it originate?

Great Mullein is native to western and central Asia and Europe (Parsons & Cuthbertson 2001; Starr et al. 2003). It is widely naturalised in other temperate regions in Asia, Canada, North America, South America, Australia and New Zealand (Starr et al. 2003; GRIN 2007), and in the United States it is a declared noxious weed in Colorado, Hawaii and South Dakota (GRIN 2007).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

VIC

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Verbascum thapsus

Other scientific names (synonyms)?

Does it have other known common name(s)?

Shepherd's Blanket, Blanket Weed, Mullein, Aaron's Rod, Jacob's Staff, Shepherd's Club, Devil's Tobacco, Flannel Leaf, Flannel Plant, Torches, Hag Tamper, Velvet Plant, Woolly Mullein, Big Taper, Hedge Taper, Velvet-leaf, Candlewick, Iceleaf, Wild Tobacco