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RESPECT THE LAND
A GUIDE TO RECOGNIZING BROADLEAF AND GRASS
WEEDS FOR EARLY CONTROL
INDEX Pigweed, Redroot 18
Prickly Sida (Tea Weed) 26
Page(s) Puncture Vine 21
Purslane, Common 25
Broadleaf Weed Characteristics 4-5
Ragweed, Common 23
Broadleaf Weed Seedling
Ragweed, Giant 23
Identification Key 6-9
Russian Thistle 21
Grass Weed Characteristics 10-13 Sicklepod 27
Grass Weed Seedling Shepherd’s Purse 30
Identification Key 14-17 Smartweed, Pennsylvania 19
Broadleaf Weed Colored Photos 18-31 Spurred Anoda 27
Sunflower, Common 23
Grass Weed Colored Photos 32-38
Velvetleaf (Buttonweed) 26
BROADLEAF COLORED PHOTOS: Venice Mallow (Flower of-an-hour) 26
PAGE Waterhemp, Tall or Common 18
Bindweed, Field (Creeping Jenny) 29 Wild Mustard 29
Bindweed, Hedge 29 Wild buckwheat 19
Blue Mustard 31
Buffalo Bur 21
GRASS AND SEDGE
Bur Cucumber 24
Bushy Wallflower (Treacle Mustard) 31
Canada Thistle 25
Brome, Downy or Japanese 33
Chickweed, Common 22
Bromegrass, Smooth 34
Cocklebur, Common 20
Copperleaf, Hophornbean 27
Crabgrass, Large and Smooth 32
Devilsclaw (Unicorn plant) 24
Fall Panicum 37
Foxtail, Yellow 36
Groundcherry, Smooth 22
Foxtail, Giant 36
Hemp Sesbania 25
Foxtail, Green 36
Horseweed (Marestail) 30
Jointed Goatgrass 33
Lambsquarters, Common 20
Sandbur, Longspine or Field 37
Marijuana (Wild Hemp) 24
Morningglory, Tall 28
Wild Proso Millet 38
Morningglory, Ivyleaf 28
Wild Oats 35
Morningglory, Pitted 28
Musk Thistle 25
Woolly Cupgrass 37
Nightshade, Eastern Black 22
Yellow Nutsedge 32
Nightshade, Hairy 22 Credit is given for many of the weed pictures for this brochure
Pennycress, Field 30 to Kansas State University, the University of Illinois, Iowa State
University, Nebraska State Department of Agriculture, American
Palmer Amarath 18
Cyanamid, BASF, Dr. Jim Nelson and Arlyn Evans.
Cotyledon and Leaf Shapes
Broadleaf Weed Characteristics
Since shape can sometimes vary, the
The leaves of broadleaf weeds are wider than approximate length to width ratio is
grasses and have branching, net-like veins. also given to assist identification.
The seed of broadleaf plants has two halves or
cotyledons, which separate on germination. The 3:1
cotyledons emerge with the seedling, expand and more
become the first visible leaves. 2:3:1
Linear Lanceolate Oval Spatulate
The true leaves develop above the seed leaves. 1:1
The shapes of cotyledons and first true leaves are
important in weed identification. Round Round with
Tapered Tip Kidney Butterfly
Cotyledon size provides additional clues. Large
cotyledons indicate large-seeded weeds such as
cocklebur, jimsonweed, morningglory and giant
ragweed. Small cotyledons are typical of weeds In this key, small cotyledons are gener-
such as pigweed, lambsquarters, nightshade, ally less than 1/2” long; large cotyledons
kochia and many others. are more than 1” long.
Relative Position of True Leaves
The next important plant characteristic
is the relative position of the first true
leaves on the stem.
Opposite Leaves* Alternate Leaves.
• One leaf per node.
• Paired leaves of similar
Leaf petioles and stem nodes in the buckwheat • Newest leaf is smaller
size attached to opposite
than preceding leaf.
plant family are encircled by a membranous sides of the same node.
papery sheath called an ocrea or stipule. Weeds in
*Note: On some weeds, all true leaves are opposite,
this family include smartweeds, wild buckwheat, but on many weeds the later leaves are alternate.
knotweeds and docks.
LINEAR (Sides nearly parallel)
ratio at least 3:1
(Narrow at tip and base)
Are the first true leaves OPPOSITE but
ALTERNATE alternate or opposite? later leaves alternate
NO YES Large cotyledons –
thick and waxy.
Large cotyledons Hypocotyl reddish
with prominent, violet tinged.
recessed midvein? Lanceolate cotyledons. Small linear cotyledons.
Older true leaves with
Nick in tip of three prominent veins.
first true leaves. Older stems develop
YES Stem reddish violet purple spots.
Hair on stems Smooth True leaves and stems hairy?
and bud area. glossy leaves,
Rough leaves, oval to ovate.
Oval to ovate lanceolate Long petiloes.
heart shaped? First true
REDROOT or COMMON PALMER True leaves
SMOOTH AMARANTH are linear,
True leaves red-violet
PIGWEED WATERHEMP without petioles.
long and below.
(See other Pigweed species below)
NO Red-violet below;
very thin Frosty or
when bruised. frosty or mealy
(needle-like) mealy above
Later leaves above.
Other weeds with linear-lanceolate Other weeds with an ocrea – Other weeds with linear-
cotyledons and first true leaves Alternate: membranous, papery sheath lanceolate cotyledons and
Buffalo Bur Cutleaf Nightshade encircling nodes and petioles: first true leaves opposite:
Pigweed species with Pigweed species without Swamp Smartweed Puncturevine (may
fine hairs on stem: fine hair on stems: Docks appear alternate)
Powell Amaranth Prostrate, Spiney and
SPATULATE OVAL OBLONG
OVATE (EGG SHAPED)
Narrow tip. Broad base.
Broadleaf Weed Broad tip. Narrow base. Rounded sides Straight sides
Length-Width Ratio near 2:1 Length-Width Ratio 2:1 to 3:1
First true leaves opposite?
First true leaves alternate?
(Later leaves may alternate)
Often purple underneath.
Leaves sparsely Leaves and •True leaves alternate.
First true leaves lobed?
hairy or smooth cotyledons very hairy YES NO •Large cotyledons.
•True leaves star shaped
(wild cucumber) or
Rough leaf surface. pentagon shaped
Later leaves (bur cucumber).
Five lobes Three lobes alternate with three
Small cotyledons Large cotyledons prominent veins.
EASTERN BLACK HAIRY
Other weeds with Ovate cotyledons:
GIANT WILD CUCUMBER
First true leaves
RAGWEED BUR CUCUMBER
Ground Cherry Chickweed Other weeds with Spatulate or Oval or Oblong cotyledons:
Horseweed White Cockle First true leaves alternate: First true leaves opposite:
Shepherd's Purse Blue Mustard Canada Thistle Spurge, Annual, Purslane
Tansy Mustard Musk thistle Jerusalem Artichoke*
Prickly Lettuce Dandelion Marijuana*, Devilsclaw*
Hemp Sesbania * Later leaves alternate
ROUND OR ROUND WITH TAPERED TIP KIDNEY
Deeply notched tip & base
Ratio near 1:1
First true leaves alternate?
First true leaves alternate. First true leaves alternate.
YES with prominent veins.
true leaves with short hairs?
First true leaves Arrowhead
Cotyledons often opposite. shaped leaves.
velvety True leaves hairy with Perennial with
Third and subsequent NO uneven margins.
leaves deeply lobed? growth habit.
Slight nick in tip
IVY LEAF MORNINGGLORY
VELVETLEAF VENICE MALLOW PITTED MORNINGGLORY WILD MUSTARD FIELD BINDWEED
Other weeds with Round cotyledons: Other weeds with Kidney cotyledons:
Other weeds with Butterfly cotyledons:
First true leaves alternate: Hedge Bindweed
First true leaves opposite: Most Morningglory species
Common Mallow Sicklepod Wild Radish
Spurred Anoda Yellow Rocket Marshelder F. Pennycress (later alternate)
Grass Weed Seedling Identification The following is a description of plant parts
and growth habits which are very useful for
identifying grass seedlings. Example grasses
Useful vegetative characteristics to
are listed (list not complete).
help identify a young grass seedling:
• The leaf blades are long, narrow, alternate
with parallel veins. Hairy Membranous Absent
• The leaf sheath encircles the stem.
• The junction of the leaf blade with the leaf
sheath is called the collar.
• Most grasses have a projection at the base of
the leaf blade called a ligule, which may be a
membrane, a fringe of hairs or a combination
Note: Ligule is absent on First leaf of most grasses
of both. Ligule is absent on first leaf.
• Grasses may be smooth (glabrous) or hairy
Leaf Sheath and Stem Type
Round to Distinctly
• Some grasses have claw-like projections at somewhat Flattened Flat
the leaf collar called auricles that partially
encircle the stem.
(Direction of twist is consistent on first leaves only)
Prominent Clasping Counter No Distinct
Clockwise Clockwise Twist
Jointed Goatgrass Most Grasses Wheat Most
Wheat, Barley, Rye Annual Bromegrasses Grasses
Leaf Midrib or Midvein
Leaf or Sheath Pubescence (Hair)
Prominent Faint or Obscure
Short Hair Long Hair
Growth Habit – Developing Plant Margin
Erect Decumbent (Reclining) Shattercane
Seed size and shape
The seed of grasses often remains
attached to the primary root after
Shattercane Crabgrass germination. If the grass seedling is
carefully removed from the soil, the
Growth Habit – Seedling (1st Leaves) seed size and shape may help identify
Woolly Sandbur Shattercane Johnsongrass
Woolly Cupgrass Wild Proso Jointed
Wild Oats or Foxtail
or Crabgrass Millet Bromegrass Goatgrass
Grass Seedling Identification Key
• No ligule Stems round or flat
YELLOW NUTSEDGE LIGULE ABSENT
LIGULE LIGULE HAIRY
MEMBRANOUS Sheath distinctly
(See next page)
flat by third leaf stage
Blade or sheath Blade and sheath
with dense hairs hairless or sparsely hairy
First leaf wide, First leaf blades
short, not erect. narrow and erect
• Blades Blades narrow, Blades wide,
• Horizontal with distinct long and erect short, not erect
growth habit. twist.
• Sheath united.
• Prominent veins.
• Sparse hairs near collar.
LARGE • Winter annual.
• Sheath flat with
• Horizontal growth habit.
CRABGRASS • Long, awned seed.
Sheath Sheath very hairy
hairy to JAPANESE BROME or
smooth DOWNY BROME
Auricles present (except
first few leaves) Note: Wheat,
Auricles absent Barley and Rye also have auricles.
Annual Winter annual Perennial
Perennial with rhizomes
• Smooth, white
• Blades and sheath • Blades erect
• Stems wire-like. • Western
erect and smooth. with distinct
• Prominent nodes. wheat region.
• Ligule jagged. twist.
• Scaly rhizomes. • Hair on blade
seed is oblong
• Large, black, shiny, • Oat-like seed. margin.
WIRESTEM ovate seed. • Long, joint-like seed.
WILD OAT • Leaves with
• Sheath distinctly
flattened. • Short ligule
• Prominent ligule. SMOOTH BROME
Blade with hair Blade with little or no hair
Blade hairy Sheath Sheath margin without hair.
on both surfaces
Blade hairy upper margin hairy Sheath occasionally with hair
or blade margins
Blade with long
hair on upper
Blade with Sheath nearly round Sheath flattened
surface near base
short hair (fuzz) Small oblong seed Large spiny seed
by third leaf stage
on upper surface
• Seedling • Occasional sparse
occasionally with hair on collar margins
hair on sheath • Sheath smooth, often
• Sheath flat,
• Underside of blade or blade, but later with reddish base
Small ovate seed
smooth or sparsely hairy smooth and shiny
• Sheath margins hairy
GREEN FOXTAIL • Prominent, white FIELD SANDBUR
reddish base midrib on older plants
YELLOW FOXTAIL FALL PANICUM
Blade & sheath
hair very short,
Blade with distinct hair dense & difficult
throughout or on margins only. to see.
Random hairs on Prominent sheath hairs
FIRSTleaf and sheath at 90° angle to stem
• First blade horizontal,
wide with blunt tip.
• Blades and sheaths • Blades hairy to • One blade margin
later smooth & shiney nearly smooth
• Very large seed
• Prominent, white midrib
on larger plants
or WOOLLY CUPGRASS
FALL PANICUM WILD PROSO MILLET
COTYLEDONS LINEAR OR LANCEOLATE COTYLEDONS LINEAR OR LANCEOLATE
REDROOT PIGWEED JIMSONWEED
(Amaranthus retroflexus) (Datura stramonium)
WATERHEMP, COMMON OR TALL PENNSYLVANIA SMARTWEED
(Amaranthus rudis or tuberculatus) (Polygonum pensylvanicum)
PALMER PIGWEED WILD BUCKWHEAT
(Amaranthus palmeri) (Polygonum convolvulus)
COTYLEDONS LINEAR OR LANCEOLATE COTYLEDONS LINEAR OR LANCEOLATE
COMMON COCKLEBUR RUSSIAN THISTLE
(Xanthium strumarium) (Salsola iberica)
COMMON LAMBSQUARTERS BUFFALO BUR
(Chenopodium album) (Solanum rostratum)
KOCHIA PUNCTURE VINE
(Kochia scoparia) (Tribulus terrestris)
COTYLEDONS OVATE COTYLEDONS SPATULATE OR OVAL
EASTERN BLACK NIGHTSHADE COMMON RAGWEED
(Solanum ptycanthum) (Ambrosia artemisiifolia)
HAIRY NIGHTSHADE GIANT RAGWEED
(Solanum sarrachoides) (Ambrosia trifida)
SMOOTH GROUNDCHERRY COMMON CHICKWEED
(Physalis subglabrata) (Stellaria media)