Rosette lawn weed and pubescent leaf and spike seed head

Weed Types

Describes a generalized group of weeds whose growing point is above ground.

A large, hardy family of plants whose growing point is below ground.

Family of plants closely related to grasses with the distinguishing characteristic of having a triangular cross-sectioned stem.

*The lists of weeds provided are not exhaustive

Botany Terminology for Weed Identification

Life Cycle

Annual– grows, reproduces, & dies back within one growing season

– Summer annuals germinate during warm seasons

– Winter annuals germinate during cool/cold seasons

Biennial– grows, reproduces, & dies over a two-year period

Perennial– live & reproduce indefinitely, may have periods of dormancy

Roots

Root Type Root Type Description Root Type Image
Taproot Long central root w/ smaller secondary roots extending out
Fibrous roots Many long, branching roots w/ smaller secondary roots extending out
Adventitious Roots formed from areas of the plant other than the root meristem, generally from the stem

Perennial Growth Structures

Perennial Growth Structure Type Perennial Growth Structure Description Perennial Growth Structure Images Rhizome

Horizontal stem that forms beneath the ground & sends up shoots above ground & roots below ground

Large carbohydrate-rich storage organ that forms beneath the ground

Horizontal stem that extends runners above ground that produce new plants w/ complete shoots and roots which produce more runners

Large storage organ that forms beneath the ground comprised of a small stem surrounded by layers of fleshy storage leaves

Leaf Shape Types

Lanceolate Linear Elliptic
Oblong Obovate Orbicular
Ovate Spatulate Reniform
Palmatisect Palmitifide Pedate
Pinnate Bipinnate Tripinnate
Pinnatifid Obcordate Trifoliate
Multifide Palmately Compound Perfoliate

Leaves grow on a single side of the stem per node

Leaves grow on both sides of the stem per node

A ring of leaves that forms around the base of the stem

A ring of leaves that forms along the stem

Round leaf margin

Crinkled leaf margin

Saw-like leaf margin

Leaflets coming off the end of a single leaf petiole

Leaflets branching out along the length of a single leaf petiole

Stem growing straight up

Stem grows up along a surface using tendrils

Stem grows up a surface by wrapping around it

Stems growing up & out

Stems growing out horizontally but curve up at the ends

Stems growing out horizontally along the ground

Grass Identification Tips

Because the leaves and flowers of grasses can often look similar to one another, being able to identify the unique anatomical features that can be used to differentiate between the various grass genera and species is important.

A spike or bristle extending off grass seeds found in some grass species

Leaf of a grass plant

Covered in hairs

Completely lacking hairs

Area at base of leaf that wraps around the stem of grass plant

Membrane or fringe of hairs near the area where the leaf sheath & blade meet (called the collar)

Extension at base of leaf blade present in some grass species; adjacent to collar between blade and sheath

Type of flower where flower clusters are attached to stem by branchlets connected to branches coming off the stem

Type of flower where flower clusters are attached to stem by branches connected to the stem

Rosette lawn weed and pubescent leaf and spike seed head

Crabgrass is one of the most common warm season annual grassy weeds. The stems grow mostly prostrate, branch freely, and send down roots where each joint comes into contact with the soil or moist grass. The sead head is divided into several fingerlike segments. Two principal species are (1) large crabgrass, sometimes known as hairy crabgrass and (2) smooth crabgrass. Smooth crabgrass tends to be smaller, less hairy, and has purplish color on the stems.

A cool season perennial wheatgrass that speads extensively by long white rhizomes (underground stems.) Leafblades are twice the width of bluegrass and tend to be rough in texture. A claw-like protrusion of the leaf called an auricle clasps the stem. One of the most distinguishing characteristrics is a ring of root hairs every 3/4 to 1 inch along the rhizomes. The lower leaf sheath of the stem is hairy.

Cool season perennials common throughout the region. The yellow flowers occur from early spring to late fall. The thick fleshy taproot, often branched, can give rise to new shoots. Seedlings may appear throughout the spring and summer and are often abundant in the fall.

A very coarse cool season perennial bunch grass. Scattered clumps objectionable in fine textured turf grasses. Leaf veins are strongly fibrous. When mowed, fibers show on the cut edge, especially if mower blades are not well sharpened. Mature leaf blades may be one-half inch wide, ribbed above and shiny smooth below. The lower portions of the steams are reddish purple, particularily in the spring and fall. A similar grass, meadow fescue, is a frequent weed in bluegrass lawns.

Foxtails are warm season annuals. Yellow foxtail has flattened stems that are often reddish colored on the lower portions. The stems of green foxtail are round. The seed of yellow foxtail is four times as large as green foxtail. Giant foxtail may be found in some lawns.

An escape from cultivation that can become a troublesome weed in lawns. The nodding, bell-shaped flowers are showy, ranging from a deep blue to purple. Creeping bellflower is a cool-season perennial with a root system that is both fleshy and fibrous. The basal leaves are heart-shaped with long stems. The leaves on the flower stalks are long and narrow without stems.

A coarse warm season annual grass with a flattened stem especially near the base. Lower portion of the platt tends to be reddish purple. The seed head branches into 6 or 8 short compact segments.

A low-growing, compact, tufted winter annual. Some flattened stems may lie close to the ground. It does not have rhizomes. Leaves are soft, light-green, and boat-shaped at the tip. Starts growth from seed in early fall and often grows throughout winter. Can produce seed heads when mowed at 1/4″. May die suddenly during summer months.

A cool season perennial. Many bluegrass lawns that contain smooth brome were started with pasture sod. The leaves are 3/8 to 1/2 inch wide and tend to be lax rather than upright. Close examination of an entire leaf will reveal an “M” or “W” across the leaf blade. The lower portion of the stem is almost white with prominent veins. Smooth brome spreads primarily by underground stems.

A decidedly warm season annual most often found growing where bluegrass stands are thin. Germinates later than crabgrass. The stems tend to be flattened and near the base are whitish in color. Flower heads are thicker and more robust than on common crabgrass. The extensive fibrous root system makes it difficult to pull.

A warm season perennial grass. The wiry fine stems root at the nodes; root system is shallow and fibrous; forms circular patches or may be distributed throughout lawn. Objectionable in bluegrass lawns because of delayed spring growth and early dormancy in the fall.

A warm season annual grass most often found in sandy turf areas that have been on low maintenance programs. Stems are flattened and branched; may be confused with yellow foxtail before formation of the spiny burs.

Warm-season perennial. Triangular stems of sedges produce 3-ranked leaves from near the ground. Leaves light yellow-green and rather harsh. Lower portion of plant is fibrous and brown. Roots often terminate with small nutlets, about the size of a kernel of popcorn. Seed heads appear burlike. Plants grow rapidly in July and August. Several species of sedge are common to our region, but this one is most prevalent in lawns.

Cool season plants, generally annuals, most often found in the dense shade of trees and shrubs. The leaves and leaflike parts form whorls at distinct internals along the weak stems. The square stems have tiny sawtoothed appendages which cause plants to stick together and to clothing. The flowers are small with four white petals.

A deep rooted perennial vine that is one of the most difficult weeds to control. The spade-shaped leaves have rounded tips and vary in size. The funnel shaped flowers vary from white to light pink and are about the size of a nickel. The plant readily climbs over shrubs and other ornamentals. It spreads by both seed and roots.

A late-starting, rapidly growing summer annual. The green, smooth stems branch along the ground in all directions from the root forming a flat circular mat on the soil surface. The light-green, smooth, tongue-like leaves are grouped five to six together forming whorls at each joint on the stem. Flowers are small, white, with several at each joint.

A perennial with creeping stems that root at the nodes. The leaves are opposite, 2-3 times longer than wide, clammy, and hairy. Flowers have five white petals. The root system is shallow and fibrous.

A cool season perennial legume that spreads by underground and above ground stems. May or may not be objectionable in lawns, depending on individual preference. Flowers white, sometimes with a tinge of pink. Seeds will live for 20 or more years in the soil.

A winter annual that starts growth in early fall. Slightly pubescent throughout. The squarish stems may be upright or spreading. Leaves are opposite with scalloped edges. Flowers are purple red.

Dock seldom flowers when growing in lawns. The plant froms a large rosette. Curly dock is most common and the leaves have crinkled edges. They are often tinted with red or purple color. Pale dock has leaves that tend to be more flat and broad. Both species have flowering stalks that may reach a height of two to three feet.

The slender, smooth, leaves are hollow and attached to the lower portion of the waxy stems. Both bulbs and bulblets are produced underground and the green to purple flowers are often replaced with bulblets. There is a characteristic onion-garlic odor. Wild onion is similar to wild garlic, but does not produce underground bulblets and the leaves are not hollow.

A winter annual that starts growth in September. Stems are squarish; plants usually upright. Flowers are lavender to blue. Leaves are opposite. A few plants may bloom in the fall, but the majority blossom in early spring.

A cool season perennial originally introduced as a ground cover, but is now a weed in many lawns. Thrives in shade, but will also grow in the sun. Ground ivy produces an abundance of lavender to blue funnel-form flowers in early spring. The square stems may root at each joint where they touch the ground.

An annual that thrives from early spring to late fall. Germination occurs in very early spring. Grows flat from a long white taproot. Individual plants may have a spread of 2 feet or more. Stems wiry, very leafy; at each leaf node there is a thin papery sheath. Leaves often have a bluish cast. Seeds are three-cornered, light-brown early and shiny black at maturity.

A versatile annual capable of adapting itself to a wide variety of environmental conditions. In lawns, it assumes a prostrate habit of growth; if not mowed it may attain a height of 7 or 8 feet. The first leaves after germination are covered with a silvery pubescence. Germination starts in early spring and continues throughout the summer. Leaves and stems vary in color from greenish yellow to greenish red.

Common mallow and dwarf mallow are the most prevalent species. The long fleshy taproot is almost white. Flowers are bluish white. The seed portion is a flattened disc which breaks into 10 to 20 pie-shaped segments.

An annual or short lived perennial legume with trailing stems that grow close to the ground. The taproot penetrates deeply into most soils. The three-leaflet leaves have prominent veins and are similar to most other clover leaves. The small clusters of flowers are bright yellow. Seed pods turn almost black at maturity. Black medic is most noticeable in lawns during June, July, and August.

A primitive form of plant life consisting of many genera and species. Moss prefers an environment that is cool and moist. It is most often found in shaded areas such as the north side of buildings and on poorly drained soil.

A warm season prostrate annual that grows from a pink taproot. The leaves are very shiny. Stems smooth, light-green to reddish green, may spread 1 1/2 to 2 feet. Seeds are lens shaped, small, and shiny black.

Cool season perennials that form rosettes with prominently veined leaves. The leaves of blackseed are oval shaped and 2 to 3 inches across with purplish stalks; broadleaf plantain has smaller leaves without purplish coloration. Both species have rat-tail like seed heads that are several inches long.

Has slender, narrow leaves that are about one inch across with 3-5 prominent veins. The seed head is a short cylindrical spike.

A prostrate freely branching warm season annual. Plants slightly hairy. Some stems may be four or five feet long. Taproot. Leaflets bright green. Flowers yellow. Seeds angled, each with 2 stout spines that give a Texas longhorn appearance.

A warm season annual. Leaves and stems fleshy or succulent, reddish in color. Grows prostrate. Root system tends to be fibrous; stems root wherever they touch the ground, particularly if the main root has been destroyed. Flowers small, yellow. Seeds very small, black.

A winter annual. The deeply lobed leaves form rosettes in the fall that may be confused with dandelions; however, the leaves lack the milky sap. Blooms in very early spring. White flowers develop into triangular seed pods filled with numerous tiny reddish brown seeds.

A low growing, cool season perennial that reproduces by creeping roots and seeds. Leaves are spear shaped. The lacy flowering stalks bloom in mid-spring with a definite reddish color. The seed is small, three-sided and reddish brown. Remains green from very early spring to early winter.

Several weedy species exist, most being winter or early spring annuals. Plants very low growing; leaf shapes vary with species but generally are small and numerous; flowers are light blue with white throats. Seed pods are divided and almost heart-shaped.

A prostrate growing warm season annual. Spotted spurge has hairy stems and leaves with a prominent purple spot on each leaf. Prostrate spurge has hairy stems and leaves but no spots. Most prominent in July, August, and September. Milky sap. Seeds are born in three’s in a capsule.

May spread by horizontal roots. Leaf form may vary. Most varieties have dark green spiny lobed leaves with crinkled edges. The lavender flowers are 3/4″ or less in diameter.

A biennial found in lawns as a rosette. Leaves are free of hair and have a light colored midrib. Leaf margins are usually edged in grey-green. Spiny. Flowers are large, powder puff in shape, and usually deep rose to violet in color.

A warm season annual that may on occasion act as a perennial. Low growing, hairy throughout. Stems branch freely in all directions, forming circular patterns of growth. Leaves vary in size and form, often are wedge-shaped and toothed. Taproot. Small funnel-form flowers are blue to purple.

Cool season perenials that are among the first plants to bloom in the spring. Prefer at least partial shade. Flower color varies from very light blue to deep purple. Occasionally become troublesom in lawns.

Classified as a perennial, but more often performs as a warm season annual. Stems branch from the base. The leaves are palmately divided into three leaflets giving a cloverlike appearance. Funnel-form flowers are yellow. The seed pod is cylindrical, 5-sided, and pointed. The plants contain soluble oxalates which give it a rather pleasing sour taste.

May grow one to two feet tall. Leaves are soft, finely divided, fern-like. Stems and leaves are covered with grayish-green fine hairs. Flowers are mostly white forming a flat flower-cluster. Entire plant is rather strongly scented.

*Illustrations and descriptions provided by Lawn Weeds and Their Control, North Central Regional, Extension Publication No. 26, 1992.