Download Cirsium arvense

Perennial
pepperweed
Lepidium latifolium
A 1 – 3 foot tall perennial
with waxy leaves, white
flowers, and creeping
rhizomes. Also known as
tall whitetop. Impacts
riparian areas and
wetlands by forming
large dense stands that
displace native plants.
Steve Dewey, Utah State University; Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Purple loosestrife
Lythrum salicaria
Linda Wilson, University of Idaho, Bugwood.org
A 8 foot tall semi-aquatic
perennial with long, showy,
rose-purple flower spikes
and square stems. Impacts
wetland ecosystems by
forming dense stands that
displace native plants and
impede water flow.
The Thistles
Chris Evans, River to River CWMA, Bugwood.org
Forest & Kim Starr, United States
Geological Survey, Bugwood.org
Steve Dewey, Utah State University, Bugwood.org
Mary Ellen (Mel) Harte, , Bugwood.org
Musk
Bull
Scotch
Canada
Cardus nutans
Cirsium
vulgare
Onopordium
acanthum
Cirsium arvense
Scotch thistle
Onopordum acanthium
Eric Coombs, Oregon Dept. of Agriculture
A 4-8 foot tall annual
with purple flower
heads and spine tipped
stems and leaves.
Plants thrive in disturbed
areas and can quickly
become the dominant
vegetation if left
unmanaged.
Canada thistle
Cirsium arvense
A 1 - 4 foot tall perennial
with small purple flowers
and prickly leaves.
Impacts a wide range of
habitats including
cropland and riparian
areas. Creeping rhizomes
can colonize an area 3 - 6
feet in diameter in just a
few years.
Steve Dewey, Utah State University; Theodore Webster, USDA Ag Research Service, Bugwood.org
Field Bindweed
Convolvulus arvensis
A twining perennial with
white, trumpet-shaped
flowers. Impacts a wide
variety of habitats
including agriculture and
home landscapes.
Control is often difficult
because plants
reproduce vegetatively
from roots, rhizomes, stem
fragments, and by seeds
that can lie dormant in
the soil for up to 50 years.
Puncturevine
Tribulus terrestris
A yellow flowering
annual that forms dense
mats and hard, spiky
seed cases that can
injure livestock, people,
and pets. Long-term
control of puncturevine
can be achieved by
consistently reducing
the amount of seed in
the soil.
Garlic mustard
Alliaria petiolata
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
A 3 foot tall biennial herb
with self pollinating white
flowers. All plant parts
have a distinctive garlic
odor when crushed.
Impacts forested
communities by altering
the soil and out
competing native plants.
Myrtle spurge
Euphorbia myrsinites
Patrick Nelson, Cottonwood Canyons Foundation
An escaped
ornamental
containing a caustic
sap that can result in
skin irritation and
swelling. Grows in a
range of habitats
from shaded oak
under stories to
sunny slopes.