Topic
Notes
References
WEEDS THAT GERMINATE IN LATE SPRING AND SUMMER
Annual Grasses
Crabgrasses, Digitaria spp.
Turf niche: universally found in all turfs; most prevalent in moist soils.
Herbicide management: selective preemergence; selective postemergence.
Large crabgrass, Digitaria sanquinalis, and smooth crabgrass, Digitaria ischaemum are annuals which persist well under most turf conditions.
large crabgrass smooth crabgrass
They are coarse-bladed and light or apple green in color.
Crabgrasses are highly competitive in turf and their spreading growth habit tends to minimize recovery by turfgrass species.
Crabgrasses can germinate throughout the entire growing season after soil temperatures have warmed in the spring.
Germination occurs after each irrigation or rainy period, thus requiring persistent control.
Yellow foxtail, Setaria glauca
Turf niche: early invader of newly established turfs; does not persist well under consistent mowing.
Herbicide management: selective preemergence; selective postemergence.
Yellow foxtail is a cool-season annual grass found throughout the United States.
Introduced from Europe, it is most prevalent in thin turfs on rich soils.
The stems are erect, branching, and compressed at the base.
Leaf blades are flat and medium in width.
The sheath is smooth and has a few long hairs at its base.
Unlike most other cool-season grasses, yellow foxtail has a ring of hairs for a ligule.
Young shoots have a rolled vernation.
The inflorescence of yellow foxtail is a narrow spikelike panicle of one-flowered spikelets.
Yellow foxtail receives its name from the yellowish appearance of the seedhead as it dries late in the season.
It is generally not a serious weed in a well-established turf but can present serious competition to seedling grasses during establishment.
Goosegrass, Eleusine indica
Turf niche: commonly found in compacted soils; will thrive at all mowing heights.
Herbicide management: selective preemergence; selective postemergence.
Goosegrass or silver crabgrass is a warm-season annual which generally germinates several weeks after crabgrass in the north during the spring.
It can grow under extremely closely mowed conditions, such as a putting or bowling green.
Under these conditions the lower portions of each stem are white or silvery.
All spikelets on the seedhead are borne on one side of a branched panicle.
Goosegrass grows abundantly in compacted or poorly drained soil.
It is found throughout the United States, particularly in irrigated turf.
Perennial Grasses
Bermudagrass, Cynodon dactylon
Turf niche: principally found in warm humid areas; persistent at all mowing heights.
Herbicide management: non-selective postemergence.
Bermudagrass is a warm-season perennial found throughout much of the United States.
It is fine- to medium-bladed and low-growing, producing both rhizomes and stolons.
Bermudagrass is extremely aggressive and one of the most rapidly growing grasses commonly found in turf.
It has a deep root system that provides tolerance to drought but is particularly troublesome in moist soils.
The seedhead of bermudagrass is a whorl of three or four racemes with small, one-flowered spikelets.
Bermudagrass is the principal turfgrass species used in warm, humid regions but can become a troublesome pest when it invades other turfs.
Kikuyugrass, Pennisetum clandestinum
Turf niche: found in warm, semi arid areas; persist under all mowing heights.
Herbicide management: selective postemergence; non-selective postemergence.
Kikuyugrass is a warm-season perennial found in southern California and Hawaii.
It is low-growing, with both rhizomes and stolons, and used somewhat as a turf species.
The stems are compact and hairy with narrow leaf blades.
The seedhead is a tightly compacted panicle at the tip of the flowering stem with two to four spikelets.
The lemma is distinctly awned.
Kikuyugrass is very difficult to control.
Nimblewill, Muhlenbergia schreberi
Turf niche: most prevalent in shaded, medium-cut turfs.
Herbicide management: non-selective postemergence.
Nimblewill is a warm-season perennial found throughout the United States with the exception of the northern border states.
Nimblewill forms bluish-green patches in the turf.
It has short, tapered leaf blades and stems that root at the nodes in contact with the soil.
The seedhead is a spikelike panicle of single-flowered spikelets.
Nimblewill is a pest in cool-season turfs, where it is generally aggressive during dry summer months, and forms brown patches during cooler periods of the year.
Zoysiagrasses, Zoysia spp
Turf niche: found in all turfs, but most prevalent in warm areas.
Herbicide management: non-selective postemergence.
Common zoysiagrass (Z. japonica) is a well-adapted turfgrass species for many places.
It can be introduced to a non-zoysiagrass turf where it becomes a troublesome weed.
Zoysiagrass is medium- to fine-bladed, and upright growing.
It has both stolons and rhizomes.
The seedhead is a compacted raceme with one-flowered spikelets resembling a spike.
Zoysiagrass is difficult to control due to its aggressive growth habit, although its rate of spread is relatively slow.
It is resistant to wear and can out compete other turf species in high-use areas.
Perennial Broadleaf Weeds
Spotted catsear, Hypochoeris radicata
Turf niche: occasionally found in medium cut turf such as golf course fairways and home lawns.
Herbicide management: selective postemergence.
Spotted catsear is a perennial that occurs throughout the northern United States from the Pacific coast through eastern Canada.
The yellow flowers of spotted catsear resemble dandelions and are generally over 1 in.
in diameter, and borne on the end of a branch stalk nearly 1 ft high.
The plant is often found as a basal rosette of irregular, round-lobed, hairy leaves with a thick milky taproot.
The flowering stems are leafless and multi-branched.
Star of Bethlehem,
Ornithogalum umbellatum
Turf niche: occasionally found in medium cut turf such as golf course fairways and home lawns in warm humid areas.
Herbicide management: selective postemergence.
Star of Bethlehem is a relatively new weed that is an escape ornamental perennial.
Herbaceous perennial from a bulb; leaves basal, narrow, strap-like, with a light green midrib; flowers in a cluster at the top of a naked stem, white to pale yellow, star-like, 6-parted.
Star of Bethlehem is a low toxin poisonous plant.
Spring Beauty
Claytonia virginica
Turf niche: occasionally found in medium cut turf such as golf course fairways for home lawns.
Herbicide management: selective postemergence.
A member of the Purslane family that sports flowers with white or pink petals with darker pink veins.
Each flower is ½ to ¾ inch (1.3 to 2 cm) wide with five petals, two sepals, and five stamens topped with pink anthers.
A pair of linear, dark green, 2 to 8 inch (5 to 20 cm) long leaves are present halfway up the stem.
Plants range from 6-12 inches (15 – 30 cm), and is common in moist woods, thickets and clearings.
Flowers appear from March-May.
This plant has an edible tuber that resembles a small potato and has a chestnut-like taste. Native Americans and colonists used them for food.
Lawn pennywort, Hydrocotyle sibthorpioides
Turf niche: occasionally found in medium cut turf such as golf course fairways for home lawns.
Herbicide management: selective postemergence.
Lawn pennywort is a perennial most noticeable during the summer in the Midwest and northeastern United States.
Lawn pennywort was introduced from Asia and was used as a groundcover or ornamental plant.
It increases by seed and stems rooting at nodes.
Lawn pennywort can be found in medium-maintained turfs.
The leaves are alternate and nearly rounded or shield-shaped, 1/2 to 1 in. in diameter, generally glossy, and with a slender petiole.
The flowers are white.