Download Noxious Weed Identification

Weed Identification
Roger Ashley
Area Extension Agronomist
Dickinson Research Extension Center
Objectives Today
1. Review State and County Listed
Noxious Weed Identification
a) Different growth stages
2.. New Invasive Weeds
Cotyledons
Page 1
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Identification and Control of Invasive and
Troublesome Weeds in North Daktoa
Extension Bulletin 1411 (Revised April 2010)
 Rod Lym, Professor of Weed Science, NDSU
 Andrea Travnicek Natural Resources Specialist
 NDSU Extension Service
 NDSU Agricultural Experiment Station
 North Dakota Department of Agriculture
 USDA-Forest Service
 Photo Credits are given on Page 2
Noxious Weeds
State
Absinth wormwood
Canada thistle
Dalmatian toadflax
Diffuse Knapweed
Leafy spurge
Musk thistle
Purple loosestrife
Russian knapweed
Saltcedar
Spotted knapweed
Yellow toadflax
Absinth wormwood
(Artemisia absinthium)
Habitat: Open fields, roadsides and waste areas
Origin: Eurasia
Seedling: Cotyledons ovate
to orbicular
Mature Plant: Taproot and
short rhizomes, erect stems
15 to 40 inches, pubescence
gray woolly sticky leaves
alternate , flower heads
nodding
Special ID Features: odor
strong, sour, sage-like
Toxic Properties: None
reported
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Canada thistle
(Cirsium arvense)
Habitat: Fields , open areas, pastures,
roadsides, bottomlands, and waste sites
Origin: Eurasia
Seedling : First leaves club-shaped, coarse,
margins serrate with spines on tips of
serations
Mature Plant : Taproot, extensive creeping
horizontal growth, erect stems branching
toward top, grooved, pubescent with
maturity, leaves alternate, sessile, slightly
clasping, oblong to lanceolate, margins
crinkled and spiny
Male
Special ID Features: Flowers rose-purple,
about 1 inch dia; plants forming patches.
Toxic Properties: Nitrate accumulation and
mechanical injury.
Female
Page 56
Leafy spruge
(Euphorbia esula)
Habitat: Pastures, rangeland, meadow, open
fields, roadsides, railroads, and waste
places.
Origin: Europe
Seedling: Leaves alternate, appearing
opposite at first, linear, glabrous.
Mature Plant: Taproot, rhizomes, Stems
erect, glabrous, sap milky; Leaves alternate,
glabrous, sap milky; Flowers open umbels,
greenish yellow.
Special ID Features: milky sap, flowers in
terminal umbel, greeish yellow.
Toxic Properties: white sap is irritant
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Musk thistle
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(Carduus nutans)
Habitat: Open areas, pastures and roadsides
Origin: Europe and western Asia
Seedling: Basal rosette, leaves waxy coarsely lobed,
3-5 points per lobe
Mature Plant: Roots fleshy taproot; Stems erect,
branched, spiny, lobed leaves extending down stem;
Leaves alternate; Flowers are 1.2 to 2 in wide.
Special ID Features: Stem winged, leaflike, spiny
Toxic Properties: Nitrate accumulation, mechanical
injury
Purple loosestrife
(Lythrum salicaria)
Habitat: Wet lands
Origin: Eurasia
Seedling: First true leaves up to ¾ in
long, opposite, oblong sessile,
prominent venation
Mature Plant: Roots fibrous from single
or branched taproot; Stems erect,
glabrous to fine pubescent, round to
angular; Leaves opposite or whorled,
alternate and small near infloresence;
Flower whorl-like cymes
Special ID Features: Flowers numerous
very showy.
Toxic Properties: None reported.
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Russian knapweed
(Acroptilon repens)
Habitat: Open fields, pastures, roadsides
waste sites and disturbed areas.
Origin: Asia
Seedling: Leaves narrow, entire, margin
toothed by third or fourth leaf.
Mature Plant: Root fibrous from taproot,
rhizomes; Stems erect, branching at base,
cover with soft grey trichomes becoming
glabrous with age; Leaves alternate,
variable pinnateifid or margins lobed;
Flower laveder blue to rose pink or purple.
Special ID Features: Erect, tall bushy
plants
Toxic Properties: None but mechanical
injury
Page 28
Diffuse knapweed
(Centaurea diffusa)
Habitat: disturbed fields, grasslands, woodlands,
roadsides
Origin: Mediterranean
Seedling: Lower leaves oblanceolate to obovate,
pinnately lobed sessile or with short petiole.
Mature Plant: Roots fibrous from taproot; Stem
erect to ascending, tall heavily branched above
midpoint, pubescence or nearly glabrous; Leaves
are alternate, basal, and lower leaves
oblanceolate to obovate, soft to stiff pubescence;
Flowers, solitary heads at tips of panicle-like
branches.
Special ID Features: Erect to ascending, spiny
bracts
Toxic Properties: None reported, mechanical
injury.
Page 30
Spotted knapweed
(Centaurea stoebe)
Habitat: Sandy soils, pastures, open areas,
railroads, roadsides and waste sites.
Origin: Europe
Seedling: Cotyledons spatulate to obovate
Mature Plant: Roots fibrous from taproot;
Stem erect, spreading or ascendign freely
branching, rough pubescent; Leaves
alternate, pinnatifid with long narrow
divisions, gray-green to gray, rough
pubescent; Flowers numerous terminal and
axillary heads lavender to pinkish.
Special ID Features: Erect, bracts not spiny
but tips of bracts are dark.
Toxic Properties: None reported,
mechanical injury.
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Dalmation toadflax
(Linaria genistifolia ssp. dalmatica)
Habitat: Pasture, range, disturbed areas
and roadsides
Origin: Mediterranean
Seedling: Stem emerges which may be
joined by one to three adventitious
stems from hypocotyl
Mature Plant: Roots rhizomatous root
system; Stems rough and woody at
base, smooth, waxy at top: Leaves
waxy, ovate to heart shape but
sometiems lanceolate, alternate and
clasping on upper portion of stem:
Flowers snapdragon like.
Special ID Feature: Erect stems broad
heart-shaped leaves
Toxic Properties: None reported
Page 70
Yellow toadflax
(Linaria vulgaris)
Habitat: Similar to Dalmation toadflax
Origin: Eurasia
Seedling: Similar to Dalmation toadflax
Mature Plant: Leaves narrow, linear, 2 in long
pointed at both ends, opposite or whorled;
Flowers
Special ID Features: Narrow leaves, flower have
“butter and eggs” appearance.
Toxic Properties: None reported
Page 71
Saltcedar
(Tamarix spp.)
Habitat: Riparian and moist areas.
Origin: Eurasia
Seedling:
Mature Plant: Roots taproot; Stem woody
herbacious reddish brown bark; Leaves are
small, flat; Flowers pink.
Special ID Features: Woody large taproot,
reddish brown bark, pink flowers
Toxic Properties: None reported.
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State
Noxious Weeds
Absinth wormwood
Canada thistle
Diffuse knapweed
Leafy spruge
Musk thistle
Purple loosestrife
Russian knapweed
Spotted knapweed
Yellow toadflax
Dalmation toadflax
Salt cedar
County
Annual sowthistle
Baby’s breath
Black hanbane
Bull thistle
Common burdock
Common Milkweed
Common tansy
Downy brome
False chamomile
Halogeton
Hoary cress
Houndstongue
Kochia
Marsh sowthistle
Orange hawkweed
Perennial sowthistle
Scotch thistle
Baby’s breath
(Gypsophila paniculata)
Habitat: Pasture, rangeland, dry areas, coarse
soils
Origin: Eurasia
Seedling: Emerge in early May and attain an
average height of five to six inches. Only one
shoot with no lateral branches develops during first
year. Flowers do not appear until the third year of
growth.
Mature Plant: Root deep taproot; Stem branching
glaborous; Leaves 4 inches long and end with a
point; Flowers 1/8 in dia white and five lobed.
Special ID Features: Small white flowers with
purple midstripe.
Toxic Properties: None reported.
Page 6
Black henbane
(Hyocyamus niger)
Habitat: pastures, disturbed areas
Origin: Europe
Seedling: Rossette leaves are alternate
and have petioles
Mature Plant: Roots large taproot: Stem
erect, leafy, thick, coarse and widely
branched; Leaves alternate, oblong to
ovate coarsely toothed to shallowly lobed,
covered with fine hairs, foul odor; Flowers
funnel-shaped, five lobed, brownish yellow
with dark purple veins.
Special ID Features: Foul odor sticky hairs
on leaves
Toxic Properties: Toxic to humans and
livestock.
Page 8
Common burdock
(Arctium minus)
Habitat: disturbed sites, stream valleys,
pastures, field, feedlots, fencerows,
roadsides.
Origin: Europe
Seedling: First leaves long broadly ovate,
pubescent, with hollow petiole
Mature Plant: Roots fibrous from large fleshy
taproot; Stems erect, branched ridged
pubescent; Leaves alternate, broadly ovate,
margins serrate to dentate, pubescent on
underside; Flower head ¾ to 1 ½ inch
diameter purple to lavender or occasionally
white.
Special ID Features: Erect, hollow lower
petioles, stems bitter tasting
Toxic Properties: None reported.
Page 12
Common milkweed
(Asclepias syriaca)
Habitat: waterways, floodplains, pastures,
roadsides and waste sites.
Origin: North America
Seedlings: Sprout emerges with opposite leaves
and prominent midveins
Mature Plant: Roots fibrous lateral; Stems erect,
usually single, containing milky sap; Leaves
opposite simple margins entire oblog oval or
ovate, fine pubescent below; Flower umbelate,
greenish purple to greenish white.
Special ID Features: Erect sout stems, mily sap,
rhizomes.
Toxic Properties: Produces cardiotoxins
Page 38
Common tansy
(Tanacetum vulgare)
Habitat: disturbed fields, roadsides, waste sites
Origin: Eurasia
Seedling: Hypocotyl with leaves resembling
mature plants though smaller.
Mature Plant: Roots fibrous from taproot,
producing rhizomes; Stems erect, coarse
branchless except for flowering portion,
glabrous to slightly pubescent; Leaves
alternate, forming large dense clumps pinnate
or deeply lobed; Flower yellow densely packed.
Special ID Features: Erect perennial with
creeping roots, showy button-like yellow flowers
Toxic Properties: produce neurotoxins and
cardiotoxins.
Page 14
Downy brome
(Bromus tectorum)
Habitat: fields, pastures, roadsides,
railroads and waste areas
Origin: Europe
Seedling: Soft pubescent leaves and
sheath, prominent membranous ligule
Mature Plant: Roots fibrous; Stems
erect, internodes glabrous; Leaves flat,
bubescent on both surfaces; Flowers
loose panicle, glumes pubescent or
glabrous.
Special ID Features: Flexuous, dropping
panicle, pubescent sheath, leaves.
Toxic Properties: Awns can injure grazing
animals.
Page 19
False chamomile
(Matricaria chamomilla)
Habitat: fields, roadsides, waste places
Origin: Eurasia
Seedling: Cotyledons broadley oblong to
ovate glabrous
Mature Plant: Roots fibrous from taproot;
Leaves alternate, linear; Flower solitary
heads terminating from branches.
Special ID Features: Erect, oderless, daisy
like flowers.
Toxic Properties: None reported.
Page 10
Halogeton
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(Halogeton glomeratus)
Habitat: disturbed areas, overgrazed pastures,
alkaline soils and semiarid regions.
Origin: Eurasia
Mature Plant: Resembles Russian thistle blue
green leaves are small sausage shaped and have
a short bristle or spine; Flowers in leaf axiles,
greenish in color.
Special ID Features: Mature plants have red
stems.
Toxic Properties: sodium oxalates poisonous to
sheep and cattle
Hoary cress
(Cardaria draba)
Habitat: roadsides, open fields, waste areas disturbed sites,
pastures.
Origin: Eurasia
Seedling: Cotyledons spatulate to ovate, smooth covered with
small bumps, leaves long petiolate ovate to oblong with toothed
margins.
Mature Plant: Roots fibrous from taproot;
Stems erect simple below, branched above;
Leaves alternate, variable, lowest ones basal,
oblong to ovate, upper leaves clasping margins
uneven or toothed; Flowers numerous dense
white.
Special ID Features: Erect perennial flowers
showy and white.
Toxic Properties None reported.
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Houndstongue
(Cynoglossum officinale)
Habitat: fields, pastures, and rocky waste areas.
Origin: Eurasia
Seedling: Cotyledons linear to oblanceolate; leaves
opposite, forming rosette, pubescent
Mature Plant: Roots fibrous from thick woody taproot;
Stems erect, herbaccious, pubescent, single stemmed;
Leaves alternate, pubescent, margins entire, lower
leaves in rosette; Flowers dull reddish purple.
Special ID Features: Erect biennial,
flowers reddish purple with musty
odor.
Toxic Properties: Plants and seeds
contain toxins that cause liver
damage.
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Kochia
(Kochia scoparia)
Habitat: fields, pastures, roadsides, waste areas.
Origin: Eurasia
Seedling: Rossette small, gray green, first true
leaves lanceolate, sessil, pubescent
Mature Plant: Roots fibrous from much branched
taproot; Stem erect spreading bushy; Leaves
alternate simple, lanceolate or narrowly linear
pubescent; Flowers in axils of upper leaves, small,
greenish changing to reddish.
Special ID Features: Erect, plant more or less
round, mature plant breaks off at soil line.
Toxic Properties: Plants contain toxins that can
cause weight lose, liver disease, and
photosensitivity.
Page 32
Orange hawkweed
(Hieracium aurantiacum)
Habitat: gardens, lawns, rangeland, fields,
meadows, rock outcrops, stream banks,
shorelines, railroads, roadsides, disturbed
areas.
Origin: Europe
Seedling: Cotyledons broadly elliptic, first true
leaves forming a rosette.
Mature Plant: Roots fibrous from rhizome and
slender stolons; Stems erect, pubescent, milky
white sap; Leaves rosette, pubescent, margin
entire; Flowers compact head, red orange.
Special ID Features: Erect perennial basal
rosette leaves spatulate to oblanceolate
pubescent.
Toxic Properties: None reported.
Page 40
Annual sowthistle
(Sonchus oleraceus)
Habitat: cultivated, disturbed areas,
roadsides.
Origin: Europe
Seedling: First true leaves form rosette,
slightly lobed, bluish gray, paler on underside.
Mature Plant: Roots fibrous from short
taproot; Stem erect, hollow, milky sap; Leaves
alternate pinnately lobed, occasionally
toothed, margins with scarce to numerous
pricles; Flowers numerous small heads ray
florets pale yellow.
Special ID Features: Erect, milky sap, weakly
prickly
Toxic Properties: None reported mechanical
injury
Page 48
Perennial sowthistle
(Sonchus arvensis)
Habitat: cultivated areas, disturbed sites, fields,
pastures, roadsides, waste areas.
Origin: Europe and western Africa
Seedling: First ture leaves with glaucous
underside and spine-tipped edges.
Mature Plants: Roots fibrous taproot,
horizontally branched; Stems erect, stout,
hollow, milky sap; Leaves alternate, shiny green,
lobes, spiny edges, base sessile and clasping;
Flowers yellow.
Special ID Features: Erect stem, hollow milky
stem, branches producing new plants, yellow
daisy-like flowers.
Toxic Properties: None reported, mechanical
injury.
Page 50
Marsh sowthistle
(Sonchus arvensis ssp. uliginosus)
Habitat: wet areas
Origin: Europe
Seedling:
Mature Plant: Roots extensive, creeping;
Stems erect with milky sap; Leaves lower
are prickly on margins, lower and middle
pinnately lobed, upper less lobed and
become clasping; Flower yellow, heads
grow in teminal flat to domelike cluster
Special ID Features:
Toxic Properties: None reported.
Page 50
Bull thistle
(Cirsium vulgare)
Habitat: Open areas, pastures,
roadsides, waste sites
Origin: Europe
Seedling: Leaves form rosette, first
leaves oblong, fringed with spines.
Mature Plants: Roots fibrous from fleshy
taproot; Stems erect, often branched,
comspicuously spiny winged by
decurrent leaf bases, pubescent;
Leaves wide, eleptic to oblanceolate;
Flower ¾ to 1 ½ inch diameter whiterose to reddish purple.
Special ID Features: Erect biennial
stem spiny-winged, marins long spined
Toxic Properties: None reported
mechanical ijury.
Page 54
Scotch thistle
(Onopordum acanthium)
Habitat: pastures, rangelands, roadsides,
railroads, waste places.
Origin: Eurasia
Seedling: first leaves densely pubescent,
silvery gray.
Mature Plant: Roots fibrous from stout fleshy
taproot; Stems erect couarse, winged by
decurrent leaf bases; Leaves basal rosette,
alternate sessile and decurrent above;
Flowers heads globose, solitary or 2 to 5 in
loose cluster, purplish or pinkish white.
Special ID Features: Erect, stems winged,
leaves decurrent, margins with long spines.
Toxic Properties: None reported.
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http://www.ag.ndsu.edu/swagronomynotes
Roger Ashley
Area Extension Specialist/Cropping Systems
Email: [email protected]
Phone: 701-690-7616
http://www.ag.ndsu.edu/swagronomynotes