Annual BlueGrass Poa Annua
Annual bluegrass grows to a height of 6 to 8 inches when left unmowed. It has light green, flattened stems that are bent at the base and often rooted at the lower stem joint. Leaf blades are often crinkled part way down and vary from 1 to 3 inches in length with typical Poa, boat-shaped leaf tips. The inflorescence (flowering structure) is a terminal panicle that varies from 1 to 4 inches in length. Seed head initiation can start as soon as plants are 6 weeks old in early fall and continue until early summer, but most seed heads are formed in spring. The annual form of annual bluegrass is a rapid and prolific seeder.
Bahiagrass forms tall, unsightly seed heads throughout the spring, summer, and fall months that many find objectionable. This necessitates regular mowing to keep the stalks from becoming too tall. The seed stems are tough and can wear out mower blades, requiring them to be sharpened frequently. High pH tends to cause yellowing of leaf tissue due to iron deficiency. Bahiagrass grows in an open growth habit, which can result in weed encroachment into sparse areas. It has a coarse leaf texture and provides less cushioning for recreational activities than some other species. Bahiagrass flourishes in full sun.
Dollarweed (Hydrocotyle spp.), also known as pennywort, is a warm-season perennial weed. It gets the common name, dollarweed, from its silver-dollar-shaped leaves. The leaves of dollarweed are round, bright green, fleshy and look like miniature lily pads measuring 1-2” in diameter with a scalloped edge. It has a low-growing habit that spreads by seeds, rhizomes and tubers. Dollarweed is often confused with dichondra. One way to distinguish the two is by looking at the placement of the leaf stem. Dollarweed has a stem located in the center of the leaf while dichondra’s stem is located at the edge.
Doveweed is a summer annual weed that usually germinates later in the growing season than most other summer annual weeds and becomes a problem late in the summer. Doveweed closely resembles a grass. Upon closer inspection, you will find that doveweed has stems that root at the nodes and purple flowers that appear on short stalks in clusters. The leaves are linear, and approximately 3/4 to 4 inches long. Leaf sheaths have soft hairs on the upper margins. Fruits are classified as capsules and are only 0.12 to 0.2 inches (3 to 5 mm) wide.
Goosegrass forms a pale green mat like clump with flattened stems that grows in a low rosette. Stems are somewhat fleshy at the base. The mature plant can spread to about 2-1/2 feet (80 cm) wide. The leaf blades are nearly hairless, except for long hairs on the blade bases, collars, and/or upper sheath margins. Leaves are keeled along the mid vein near the base of the blade. Sheaths are open, flattened, keeled, and are whitish at the base around the collar.
Knotweed Stems are stout, cane-like, and reddish-brown. The plants die back at the end of the growing season but their old reddish-brown canes often persist. The stem nodes are swollen and surrounded by thin papery sheaths. Leaves are either heart-shaped or spade-shaped or somewhere in between. The flowers are small, creamy white to greenish white, and grow in showy plume-like, branched clusters from leaf axils near the ends of the stems. The fruit is 3-sided, black and shiny.
Field sandbur (grassbur) is a summer annual grassy weed that can be found in home lawns, sports fields, parks and along roadsides. This weed is especially adapted to dry, sandy soils but can be found growing in other types of soils as well. The big problem with this weed is the sharp, spiny burs that are part of the inflorescence. These burs can be painful and are difficult to remove from clothing material. Field sandburs (grassburs) generally start germinating in late spring and will continue to germinate until late summer or early fall months. This weed will continue to grow until the 1st hard frost or freeze occurs in the fall.