Dallis Grass

Dallis Grass/Dallisgrass (Paspalum dilatatum)

This is a warm season perennial and found more predominately in humid areas of the southern United States. Outside of turf grasses, it can also be seen along roadsides and ditches, especially in sandy and clay soils.

This grass has coarsely textured yellowish-green leaf blades that grow 1/2 inch wide. If left unmowed, leaves can grow about 10 inches long. There is a white vein down the middle of the leaf with hairs and there is a purplish coloration at the base.

As the weed continues to grow multiple leaves produce a round clump that has a jagged, hard-edged appearance. It then spreads within clumps by rhizomes.

The rhizomes are visible on Dallis grass.
This is a good way to distinguish it from other common clumping grasses where rhizomes are not seen, like crab grass.

Stems shoot up from the
center which have long
seed heads on top.

These seed heads are
sometimes referred to as
a 'shaking rattlesnake tail'
and have 3 to 6 seed heads
on the top of one stem.

Photo: Franz Xaver

Seed heads average 4 inches but can be as long as one foot. They bow out at a 45 degree angle from stem, then arch and droop down. Each head consists of flat rows with oval seeds along it's entire length. They are pale green to a purplish color and are covered with black silky hairs.

Dallisgrass is hard to control and will grow to a height of 5 feet if left unmowed. It is competitive and can take over if conditions are right. It spreads through seeds and rhizomes and can be difficult to remove. For manual removal try digging out to get creeping stems. If hoeing, do this regularly and mulch.

Use an inorganic mulch like solarizing black plastic mulch for a number of weeks, place mulch on top and apply a preemergent in spring. Using a pre-emergent herbicide religiously when winter breaks to kill seeds before germination when soil temperatures warm, about 53 degrees.

Post-emergent's can be used in summer. Spray with MSMA or CAMA crabgrass herbicide at frequently and according to directions. Again, be cautious of using post-emergents, many are non-selective and can kill other vegetation and grasses.

FYI:

Dallis and Bermuda Grass can sometimes be confusing to distinguish between. Both spread by seed and rhizome, but Bermuda is thinner and does not spread as quickly as Dallis.
This is related and similar looking to knot grass/knot weed (Paspalum distichum), which is also a clumping perennial grass.

Both have forage qualities but Dallis grass seed heads are susceptible to a microorganism called ergot fungus which is toxic should animals or livestock consume it. The toxins that produce ergot poisoning are alkaloids that show neurological symptoms, along with many other bad side effects.
This grass weed was named after A.T. Dallis, who considered this to be a good forage grass around 1900. Since then this perennial has become viewed as a nuisance.

Related Articles:

Easy Understanding of Herbicides
Outline to understand different weed killer methods.

Growing Plants from Seed
More suggestions for removing weed seeds.

Back to Weed Identification

Back from Dallis Grass to home page Easy Butterfly Garden