Sweetbriar
LAWRENCE JENKINS
E. R. JACKMAN
SWEETBRIARRosa rubiginosaShowing stem with leaves and flowers, cluster of fruit
after blooming, nature of root growth, and seed. Seed magnified 3 diameters.
Oregon State System of Higher Education
Federal Cooperative Extension Service
Oregon State College
Corvallis
Extension Bulletin 578
November 1941
Sweetbriar
(Rosa rubiginosa)
By LAWRENCE JENKINS and E. R. JACKMAN*
Illustrations by Cathrine Davis Young
Other names: Wild rose, Sweetleaf rose.
Originally used for an ornamental, sweetbriar is one of the numerous
plants that have escaped cultivation and become pests in pastures, fields, and
waste places. It is a perennial that reproduces by seed. This attractive, sweetsmelling shrub is common in western Oregon in unplowed pasture land. In
some cases, it spreads quite rapidly and materially decreases the carrying
capacity of the pasture.
Sweetbriar commonly grows from 2 to 7 feet tall. It is covered with
sharp, curved thorns. Young growth and the surface of the seed receptacle
are generally covered with numerous short, straight, stiff bristles. Leaves are
produced alternately along the sterns. Five to seven leaflets are borne on small
stalks branching from the main stern. The leaflets have saw-toothed margins, are
round to oval shaped, and to lb inches long. They are dark green and
smooth on the upper surface, and on the underside are pale green and covered
with minute glands that secrete a sweet-smelling substance. Flowers are an
attractive bright pink, produced singly in most cases, but occasionally there
are two or three in a group. They are lb to 2 inches across. "Seeds" are strawcolored, hard, and covered with small hairs.
Control. Large areas should be plowed up and given a period of summer
fallow before seeding back to pasture. Several methods can be used to remove
the thorny foliage in preparation for plowing. A rod or a chain can be used
to pull out many of the plants if they are thick. Scattering plants can be
destroyed with a weed burner. Vines should first be burned around the base
just enough to crack the bark. In a few days the tops will have died down
and then can easily be burned to the ground. Several burnings with a weed
burner will kill the pest. Small areas can either be grubbed out or sprayed
with sodium chlorate. Dry treatments of sodium chlorate on sweetbriar have
not given as good control as spray applications. The spray should be made by
mixing about 1i pounds of the chemical to a gallon of water. The foliage,
stems, and crown should be sprayed thoroughly until the liquid is dripping from
the leaves. Spraying should be at full-bloom stage. On drying, the sprayed
plants become very inflammable. Precautions to follow when using sodium
chlorate and information on other methods of controlling perennial weeds are
discussed in Extension Bulletin 510.
This is one of a series of 39 bulletins discussing 58 perennial weeds in
Oregon and their control. A list of bulletins in this series will be found on
the last page of Extension Bulletin 510. The individual bulletins are punched
so that several may be bound together if desired.
ACKNOWLEDGMENTS: The authors thank Dr. Helen M. Gilkey, Curator of the Her-
barium, for reading the manuscript and checking the description of the plant. Professor
G. R. Hyslop, In Charge, Division of Plant Industries, made many helpful suggestions.
E. R. Jackman is Extension Specialist in Farm Crops and Lawrence Jenkins is
Assistant Extension Specialist in Farm Crops at Oregon State College.
Cooperative Extension Work in Agriculture and Home Economics
Wm. A. Schoenfeld, Director
Oregon State College and United States Department of Agriculture, Cooperating
Printed and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914