First introduced in Australia as an ornamental garden plant from Europe and Central Asia, Great Mullein is now frequently found in temperate areas of New South Wales, Queensland, South Australia, Victoria and Western Australia.
Great Mullein favours dry, well drained sites but it is also found in shallow soils, along rocky hillsides, in cultivated pastures grasslands, along roadsides and watercourses. The weed is able to flourish in shallow soils with low fertility making the risk of spread high in neglected areas.
Although not a particular invasive species of weed, Great Mullein still causes concern for agriculture as it is a potential reservoir of the cucumber mosaic virus and harbours a variety of pests and insects that can target other crops. In order to maintain productivity, Great Mullein must be controlled to ensure that such pests are kept at a distance.
Great Mullein is an erect herb that is capable of reaching heights exceeding 2.5 metres in height with a basal rosette up to 60cms. The single stem of the weed is covered in wooly white hairs and produces grey-green fuzzy leaves and small, densely arranged yellow flowers. A prolific seeder, Great Mullein bears oval shaped green hairy capsules that are 7 to 10 mm long that change colour to brown once dry. Each of these capsules contains 600 tiny seeds that either fall close to the parent plant or are carried further afield by insects or birds. These seeds germinate in spring and autumn and the viable seedlings develop to form a large rosette by summer.
There are two methods for the removal of Great Mullein plants that are considered to be the most effective means of controlling outbreaks of the weed. Physical removal is suitable for smaller infestations, however this can be labour intensive and time consuming as some plants can grow to be very large and have an extensive taproot system.
Treatment with a registered herbicide and reliable engine driven spray unit is a fast and easier way of targeting Great Mullein plants. For an effective kill, coat the foliage thoroughly and allow the herbicide to run off the leaves and stem of the plant. With a few days the plants will begin to wither and die however repeat treatments may be required when dealing with denser infestations.
For further information on the most effective spray equipment for eradicating Great Mullein infestations, click here or call 1800 011 000 for expert advice.