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Volcanoes park,
UH botanists suggest ways
to get rid of weed
on Mauna Loa

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By Harold Morse
Star-Bulletin

Mullein is not a household name, but it is the name of a tall plant species with spikes of yellow, lavender or white flowers, one type of which grows on Mauna Loa in Hawaii Volcanoes National Park.

The state considers it a weed.

According to a University of Hawaii botanical study, it's believed an estimated 200 worker days a year will be needed to remove mullein from existing sites.

Hawaii Volcanoes National Park and the Pacific Cooperative Studies Unit of the UH botany department issued the 19-page report surveying the plants and efforts to remove them.

It's recommended that cooperative agreements with private and state landowners be made to control mullein in land adjacent to the park. Use of herbicides and biological controls as alternatives to the weeding practice of manually uprooting mullein should be investigated, the report concludes.

Localized efforts to eradicate it along park roadsides began in 1989. The report concentrates on such efforts in the years 1994-1999. Common mullein, which grows on Mauna Loa, reaches six feet.

Mullein occupies more than 2,400 acres of open lava flows at medium elevations in the park and is said to be expanding its habitat there. Weeding out mullein effectively reduces populations by the third or fourth year of such weeding, and successful control requires consistent and thorough follow-up treatment, the report says.

Researchers describe common mullein as a biennial herb naturalized in mostly temperate places on the Big Island, noting it was first observed growing on Mauna Loa in the 1970s.