Bupleurum rotundifolium L.
Hare's-ear, Hound's-ear, Thorough-wax (Thorow-wax)| Category |
|---|
| Forb/Herb |
Description
Height
This annual or short-lived perennial herb grows 18-24 inches (45-60 cm) in height.Leaves
The blue-green leaves of this species are perfoliate, appearing pierced by the stem. They have smooth margins and are somewhat round.Flowers
The star-shaped, chartreuse flowers begin to bud in April and are in full flower by early June. Flowers are found in groups of 7-12 in umbels with green bracts.Fruit
Seeds mature by early summer and remain on the stalks (even after stalk death) until September or October. Seeds disperse slowly throughout this period.Life History
Hare’s Ear is an annual or short-lived perennial herb that self-sows readily. It is in the Apiaceae (Carrot) family, notable for the production of secondary compounds that can be skin irritants when handled. Proper protection should be taken when managing. Seeds are available in the nursery trade where it is sold as a garden plant and used for flower arrangements. There is little additional information regarding this species’ life history.Origin & Distribution
The origin of this species is unknown, though it is possibly from Asia. This species is now found across much of eastern North American, in all states east of the Mississippi River excluding Alabama and South Carolina. It has also be reported as far west as Arizona and Texas and as far north as South Dakota. In Tennessee, it has been noted in the limestone cedar glade communities.Sources
Baskin, J. M. and C. C. Baskin. 1974. Some aspects of the autecology of Bupleurum rotundifolium in Tennessee cedar glades. Journal of the Tennessee Academy of Science 49: 21-23.The Nature Conservancy. 1999. Weed Notes: Bupleurum rotundifolium.
http://www.imapinvasives.org/GIST/ESA/esapages/buplrotu.html
USDA PLANTS Database: Burpleurum rotundifolium L:
http://plants.usda.gov/java/profile?symbol=BURO
Management Recommendations
Mechanical Control
Hand Pulling: Hand clipping or pulling may be effective in controlling this species, though some report increased root growth from these measures. Due to the production of secondary compounds that can be skin irritants in the family (Apiaceae), care should be taken during management of Hare’s Ear.Mowing: Baskin and Baskin (1974) report that the plant is typically not found in areas that are mowed or plowed during the late spring summer, which they attribute to the fact that the plant typically grows taller and lasts longer than most annual species in Tennessee.
Chemical Control
There are no reported chemicals known to treat this species effectively.Glyphosate herbicides, trade names Roundup®, Roundup® Ultra, Rodeo®, and Accord are amino-acid inhibitors are non-selective herbicides that will kill broadleaved plants and grasses. They have been reported as 74% effective when used on wild carrot (Daucus carota), another member of the Apiaceae family.