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Weed Identification

Virginia Tech College of Agriculture and Life Science Virginia Cooperative Extension

Texas panicum

Family

Poaceae

Scientific Name

Urochloa texana
Weed photograph 1
Weed photograph 2
Weed photograph 3
Weed photograph 4

Other Common Names:

Texas signalgrass

Synonyms (former Scientific Names):

Panicum texanum
Brachiaria texana

Habit

A spreading summer annual that may have an erect growth habit or grows close to the ground with tips ascending (decumbent growth habit). Texas panicum may reach as much as 32 inches tall and can root at the lower nodes.

Leaves

Leaf blades range from 3 to 11 inches in length and may reach as much as 4/5 inch in width. Leaves are covered with short, soft hairs on both surfaces. Auricles are not present and the ligule is membranous and fringed with hairs, from 1 to 1.8 mm long.

Identifying Characteristics

A summer annual with relatively wide leaves that are covered with soft minute hairs on both surfaces. Texas panicum is very similar in appearance and growth habit to Broadleaf Signalgrass (Brachiaria platyphylla). However, broadleaf signalgrass has hairs only along the leaf margins unlike Texas panicum. Additionally, the two can be distinguished in the seedling stage by the lack of hairs on the leaves of broadleaf signalgrass compared to the small velvety hairs on both leaf surfaces of Texas panicum. Texas panicum seedlings also very closely resemble Large Crabgrass (Digitaria sanguinalis) in appearance. Once ligules become noticeable, however, the two can be readily distinguished from one another. Large crabgrass has a relatively tall membranous ligule with jagged edges while Texas panicum has a ligule that is membranous at the base but fringed with hairs on the top. Stems may be erect to as much as 32 inches in height or may grow close to the ground with tips ascending (decumbent growth habit). Stems may reach as much as 4 1/2 feet in length and plants can root at the lower nodes. Stem nodes are distinctive and are also covered in soft hairs. Seedlings of this grass weed have leaf sheaths and blades that are covered with soft hairs on both surfaces. First leaves are relatively broad compared to most annual grasses. The fairly large seed from which seedlings arise also helps in the identification of this species.

Flower Seed Head

Seedhead a simple, narrow panicle that ranges from 2 3/4 to10 inches in length. Each 'spike' has 2 rows of spikelets that are each approximately 3 mm long.

Seed Fruit

Seeds are light brown in color and approximately 5mm in length.

Where Found

Texas panicum is found throughout the southeastern United States and has developed into a significant weed of agronomic crops.

Leaf Hair on Upper Surface

hairs from base to tip

Leaf Arrangement

rolled in bud

Mature Leaf Width

Varies: 
6 to 15 mm, 
more than 15 mm

Stem

flat or oval

Seedhead

panicle

Root Structure

fibrous

Life Cycle

summer annual

Auricle

not present

Ligule

Varies: 
membrane, 
hairy

Ligule Length

Varies: 
less than 1 mm, 
1-2 mm

Plant Type

Grass