Download The Nature Conservancy

Weed Notes: Bupleurum rotundifolium
TunyaLee Morisawa
©The Nature Conservancy
Wildland Weeds Management and Research
http://tncweeds.ucdavis.edu
10 August 1999
Background:
Bupleurum rotundifolium is commonly called hare's ear, thorow-wax and hound's ear. Seeds of B. rotundifolium are
sold for gardening and the plant is used in flower arrangements. A member of the carrot family (Apiaceae), B.
rotundifolium possibly originated from Asia. Very little information for the control of this plant was found. In fact,
most information was on how to grow the plant since it is useful for its medicinal constituents. Numerous papers
about the secondary compounds (saponins) of Bupleurum falcatum were available and most information below is on
this species.
Reproduction:
The seeds of B. falcatum often have a low rate of emergence and require a long emergence period. High and
constant soil moisture increased the number of emerging seeds and also the time period for emergence. Seed
germination rates were highest at 15° C. The germination rate was very low at 25° C and zero germination was
observed at 35° C.
Preventative Measures:
Mulches are not recommended because they increase soil moisture and may result in higher germination of seeds.
Dry stressing 7-month rosettes and bolting plants of B. falcatum (keeping the plant near the wilting point)
demonstrated that the aerial parts of the rosette were reduced but dry stress did not affect the growth of the root in
both the rosettes and bolting plants.
Mechanical Control:
If hand pulling, the use of gloves is recommended since the secondary compounds common in the Apiaceae family
can irritate skin. Clipping the aerial part of the plant may actually increase the weight of the root. Techniques such
as deep ploughing may also increase root weight. Disbudding increased the viability of plants and increased the
weight of the root.
Chemical Control:
A dicamba and 2,4-D mixture may provide control. 2,4-D alone will reduce populations but not kill all plants.
Roundup may also be an effective control measure (J. DiTomaso, personal communication).
For wild carrot (Daucus carota), glyphosate did provide >74% control when applied at 0.84 kg ai/ha. 2,4-D ester
was less reliable when applied at 1.12 kg ai/ha, providing 18% control at one site and 88% at another (Stachler and
Kells, 1997).
References:
1. Choi, B-R; Kang, S-W; Park, K-Y; Kim, D-H. Effects of mulching on emergence and yield of Bupleurum
falcatum L. RDA Journal of Agricultural Science Upland & Industrial Crops, v.37, n.2, 1995:106-110.
2. Hosoda, K; Noguchi, M. Studies on the Cultivation of Bupleurum-Falcatum L. IV. Effects of Disbudding and
Picking Flower on the Root Growth and Root Morphology Shoyakugaku Zasshi, v.47, n.1, 1993:39-42
3. Minami, M; Sugino, M; Hata, K; Hasegawa, C; Ohe, C. Effects of light and temperature on germination rate,
development of embryo and change of saikosaponins content during germinating process in the seeds of
Bupleurum falcatum. Natural Medicines, v.51, n.1, 1997:40-44.
4. Minami, M; Sugino, M; Sadaoka, M; Hasegawa, C; Ohe, C; Ashida, K; Ogaki, K. Physiological response and
improvement of tolerance to environmental stress in Bupleurum falcatum L. (II) comparison of sensitivities to
dry stress between Rosette and bolting plants. Natural Medicines, v.49, n.4, 1995:401-408.
5. Montazeri, M. Annual broadleaf weeds and their chemical control in dryland wheat in Bakhtaran [Iran]. Iranian
Journal of Plant Pathology, n.1-4, 1987:11-12.
6. Qie, C; Li, G; Song, Q; Suo, J; Sun, D; Sun, Y; Lu, M; Lin, M. Studies on the high yield techniques for
Bupleurum falcatum L. Zhongguo Zhongyao Zazhi, v.20, n.2, 1995:76-78, 126.
7. Stachler, J.M. and Kells, J.J. 1997. Wild carrot (Daucus carota) control in no-tillage cropping systems. Weed
Technology v.11, n.3:444-452.
—HUMULUS.DOC—