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Weed Identification

southern crabgrass

Family

Poaceae

Scientific Name

Digitaria ciliaris

Other Common Names:

saulangi
tropical crabgrass
fingergrass
Henry's crabgrass
kukaepua'a
smooth crabgrass

Synonyms (former Scientific Names):

Syntherisma marginata
Panicum adscendens
Digitaria adscendens
Digitaria sanguinalis var. ciliaris
Panicum ciliare

Habit

Southern Crabgrass can grow in any open ground that is sunny, in turf, flowerbeds, etc. It sprouts up in March (as the soil warms up) and grows through to frost (October or November). Southern crabgrass can root from the lower nodes giving it a decumbent habit.

Leaves

Southern crabgrass leaves are around 2-7 inches long and less than an inch wide. The leaves are occasionally pubescent on the upper surface but the sheaths are densely pubescent. This grassy weed has a small membranous ligule with a frayed edge.

Identifying Characteristics

Southern Crabgrass is a valuable temporary summer forage crop, particularly on open land that is planted to vegetables or row crops, and rotated into pasture for livestock grazing or haying.

Flower Seed Head

Seedheads have 2-9 spikelets that are around 1-8 inches long.

Seed Fruit

Seeds are light brown and are less than 1mm wide and approximately 4-5mm long.

Where Found

Southern crabgrass occurs northward on the coastal plain occasionally to Connecticut, more common southward east of the Appalachian region, throughout Florida, extending west into Texas and north into Kansas and Nebraska. Also occurs in the West Indies, Mexico, Central and South America.

Leaf Hair on Upper Surface

Varies: 
no hairs
hairs from base to tip
hairs on basal half only

Leaf Arrangement

rolled in bud

Mature Leaf Width

Varies: 
less than 5 mm
6 to 15 mm

Stem

flat or oval

Seedhead

multiple spikes

Root Structure

fibrous

Life Cycle

summer annual

Auricle

not present

Ligule

membrane

Ligule Length

Varies: 
less than 1 mm
1-2 mm
2-3 mm

Plant Type

Grass