Onionweed
Family
Liliaceae
Asphodelus fistulosus
Designation/Status
Arizona Priority Weed List - Listed
Federal Noxious Weed List - Terrestrial Noxious Weed
Origins
Native to southern Europe, Mediterranean Africa, and western Asia.
Plant Characteristics
Life Cycle: Leaves sprout after
winter rains (winter monsoon season). Flowers appear in spring.
Prolific seeder and aggressive species that can establish on
disturbed ground quickly. Plants die to the ground during the dry
season. Has a tuberous root system.
Visual Appearance:
An erect, clump-forming, herbaceous perennial in the lily (Liliaceae)
family that grows to about 1 foot tall and almost as wide. Long,
tapering, round, hollow leaves form clusters that resemble chives
or scallions and, therefore, could be confused with some native
onions (Allium spp.). However, size and habitat is key in
discerning the difference. Flowers are less than a half-inch
across, flat and white with six petals. In the center of each
petal is a thin pink to brown line. The flowers are arranged on
branched spikes that reach nearly 2 feet high. Fruits are1/8-inch
round capsules.
Habitat
Onionweed was introduced as an ornamental and is an
attractive plant, but becomes problematic because of its
aggressive nature. It easily escapes cultivation, once
established, into non-irrigated land. Large populations can
establish quickly due to its prolific seeding capability. There
is a tendency for it to invade land that has been disturbed, so it
is not known whether it will be a threat to natural vegetative
communities.
In
the Sonoran Desert region, this weed seems to do best in areas
above the desert that receive moderate winter rainfall. In
Arizona, plants have been found from about 2,000 feet in elevation
to at least 4,500 feet and documented in Pima and Santa Cruz
counties.
Control Measures
Mechanical and Cultural:
Still offered by some nurseries as an ornamental, do not buy or
plant it, as it is a prohibited noxious weed in many states,
including Arizona, and is a federally listed noxious weed.
Eradicate it immediately if found on your property. Do not try
pulling this weed, as the tops off the leaves would break off and
the tuberous roots would still be left underground. Instead, dig
them up by the roots to be sure to get the whole plant. Plants
should be discarded in plastic (garbage) bags to contain all parts
of the plant, especially the capsules, if present.
Biological: None.
Onionweed is unpalatable to livestock and wildlife.
Chemical:
Use of herbicide has been helpful in managing Onionweed.
Other Points of Interest
Introduced into the United States in the 1980s and offered for
sale in Alpine, Texas and Phoenix, Arizona by 1984. The species
was documented in 1930, as a naturalized population near Saltillo,
Coahuila, Meixco, where some of the original U.S. plants were
collected. Also called: Pink asphodel, hollow-stemmed
asphodel.References:
http://www.dpiwe.tas.gov.au/inter.nsf/WebPages/SLEN-5NG5KK?open
http://www.desertmuseum.org/invaders/invaders_onionweed.htm
http://cals.arizona.edu/yavapai/anr/hort/byg/archive/onionweed.html
