Annual Broadleaf Weeds

Bedstraws, Galium spp.

Turf niche: occasionally found in high cut turf such as golf course roughs.

Herbicide management: selective postemergence.

Bedstraws are annuals, multibranched, with narrow, rough leaves, in a circle of six to eight on jointed stems.

The flowers are small, white, have four petals, and are borne on slender branches attached to the joints of the stem.

The seeds are formed in round pods that have stiff bristles.

Bedstraws can be found throughout the eastern United States and northwest coast but do not persist in closely mowed turf.

Buffalobur, Solanum rostratum

Turf niche: low, dispersed populations in sandy or course soils. Does not persist under close mowing.

Herbicide management: selective postemergence

Buffalobur is an annual that generally occurs in low-fertility soils.

The stems are multibranched, can reach heights of 24 in., and are covered with hairy, long, stiff, yellow prickles.

The leaves are long, alternate on the stem, are dense and hairy, and cut into deep, rounded lobes.

The flowers are yellow with five lobes and form a spike with rough burs that enclose the seeds.

Buffalobur is found mostly in semiarid regions.

Carpetweed, Mollugo verticillata

Turf niche: normally only a pest during establishment

Herbicide management: selective postemergence

Carpetweed is an annual with smooth, tonguelike leaves.

The stems branch in all directions, forming flat, circular mats.

Carpetweed is slow to germinate in the spring but spreads rapidly in hot weather.

Its many branches radiate from a single taproot.

Single leaves are arranged like wheelspokes around the nodes.

Small greenish-white flowers arise from the leaf axils.

Carpetweed occurs in turfs throughout the United States.

Carolina geranium, Geranium carolinianum

Turf niche: Mostly found during a establishment. Not competitive in low cut turf.

Herbicide management: selective postemergence

Carolina geranium is an annual or, sometimes, a biennial.

Its root system is fibrous; stems are erect and branch at the base, reaching heights of 20 in.

The leaves are 1 to 3 in. across and alternate with deeply cut fingerlike divisions.

The flowers are small, five-petaled, pale pink to lavender, and generally occur singly or in loose clusters at the tips of stems and branches.

Carolina geranium can be found throughout most of the United States.

Prostrate knotweed, Polygonum aviculare

Turf niche: found in all turfs, particularly in compacted soils.

Herbicide management: early preemergence; selective postemergence

Prostrate knotweed, an annual, is low-growing and appears early in spring.

Its features vary depending on its maturity.

Young plants have long, slender, dark green leaves that occur alternately on a tough, knotty stem.

Mature plants have smaller, dull green leaves and inconspicuous white flowers.

The swollen, or knotted, joints along the stem are covered with a thin, papery sheath.

Knotweed persists in soil-compacted areas and is an excellent indicator of compacted soil or areas of excessive wear.

It occurs throughout the United States but is particularly abundant in cool areas.

Common lambsquarters, Chenopodium album

Turf niche: problem only in establishment or high-cut turf

Herbicide management: selective postemergence

Common lambsquarters is an annual widely distributed throughout the United States.

The stem arises from a taproot and is smooth with red or light green stripes.

It can obtain heights of 3 to 4 ft.

The extent of stem branching varies considerably, depending on other plant competition.

The leaves are alternate, 1 to 3 in. long, with a distinct white, mealy coating on the underside.

The edges are somewhat toothed.

The flowers are small, green, without petals, and borne on the ends of branches and in the axils of stems.

Common lambsquarters does not persist well in mowed turf but can be troublesome in newly established sites.

Common mallow,
Malva neglecta

Turf niche: low populations in low to medium cut turf; uncommon in medium fertility.

Herbicide management: selective postemergence

Common or roundleaf mallow is an annual or short-lived perennial.

It has a long taproot and rounded leaves with five distinct lobes.

The leaves are opposite on the stem and closely resemble those of ground ivy, for which it is sometimes mistaken.

The flowers have five pinkish-white petals and arise from the leaf axil on the main stem.

Unlike ground ivy, the spreading branches of mallow do not root at spots that touch the ground.

Common mallow can be found throughout the United States but is especially persistent in cool regions.

Prostrate pigweed, Amaranthus blitoides

Turf niche: only found in new establishments or high-cut turf.

Herbicide management: selective postemergence

Prostrate pigweed is an annual that is most often-found in farm fields.

Its prostrate growth habit can present a problem in newly established sites.

Pigweed is a prolific seed producer and has good tolerance to hot, dry weather, competing well under such stress.

The leaves are spearshaped, dull green, and covered with dense, coarse hairs.

Red or light green stripes run the length of the main stem.

The seed develop in bushy terminal spikes and along the leaf axils.

Prostrate pigweed occurs throughout the United States.

Puncturevine Tribulus terrestris

Turf niche: generally found in low fertility, medium-too high cut turf.

Herbicide management: selective postemergence

Puncturevine is an annual found in warm, humid or arid regions.

It has multibranching, hairy stems, arising from simple taproots and a prostrate growth habit.

The leaves are compound, oblong, opposite, and hairy.

The flowers are small, yellow, five-petaled, and produced in the leaf axils.

The seeds mature in a pod containing five sharp burs stiff enough to penetrate shoes or golf-cart tires.

Puncturevine therefore presents a serious problem even in low populations.

It occurs throughout the southern half of the United States.

Common purslane, Portulaca oleracea

Turf niche: commonly in low fertility open turfs.

Herbicide management: selective postemergence

Common purslane has a fibrous root system with thick, succulent, often reddish stems that form dense mats 1 foot or more in diameter.

It thrives well in extremely hot, dry weather due to its ability to store moisture.

The leaves are alternate, or clustered, and thick and fleshy, similar to those of a jade plant.

The waxy coating on the leaves not only minimizes water loss, but also makes common purslane difficult to control with herbicides.

The flowers are small, yellow, and occur in the leaf axils.

The seeds may be dormant in the soil for many years.

Common purslane is widely distributed and occurs throughout the United States.

Annual sowthistle, Sonchus oleraceus

Turf niche: infrequent in low fertility turf; basal rosette can survive under medium mowing height.

Herbicide management: selective postemergence

The stem is smooth, 1 to 6 ft tall, and has a milky juice.

The erect growth habit does not allow persistence under mowing conditions.

Annual sowthistle is thus a problem only in newly established sites.

The leaves at the base of the stem have short petioles, while leaves at the top of the stem are directly attached.

The leaves are long and deeply toothed with short spines at the margin.

The flowers occur in light yellow masses, similar to a daisy, and are borne on stalks at the top of the plant.

Annual sowthistle can be mistaken for dandelion.

Prostrate spurge, Euphorbia humistrata and E. supina

Turf niche: common, but in low populations in medium height cut turf.

Herbicide management: selective postemergence

The stems are prostrate, forming a mat.

The leaves are opposite and frequently have a red blotch in the center.

The stem, when broken, oozes a milky sap.

Prostrate spurge occurs throughout the northern United States and persists well under closely mowed turf.

Spotted spurge, Euphorbia maculate

Turf niche: not as common as prostrate Spurge, but with similar characteristics.

Herbicide management: selective postemergence

Spotted spurge is an annual similar to prostrate spurge.

It germinates in late spring or early summer and has a shallow taproot.

It is more erect in its growth, however, than prostrate spurge but can spread from 6 in. to 3 ft.

There is generally less (than prostrate spurge) but larger leaves on the stem each leaf with a conspicuous red blotch in the center.

Spotted spurge is found throughout the eastern United States, being more abundant in warmer areas.