Paspalum urvillei

Common Name: vaseygrass

Family: Poaceae

Common Synonyms: Paspalus ovatus var. parviflorus

USDA Hardiness Zone: 8a-11b

Growth Habit: Perennial grass

Origin: South America

FISC Category: -

FDACS Listed Noxious Weed: No

Introduction Date: Introduced to the U.S. as a pasture grass in the late 1800s. Earliest Florida specimen vouchered in 1943

IFAS Assessment:

• North: OK
• Central: OK
• South: OK

Description

Plants perennial; cespitose, with a knotty base composed of very short (less than 1 cm) rhizomes. Culms 50-220 cm, erect; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 1-4(7.7) mm; blades 12-60 cm long, 2-12 mm wide, flat, mostly glabrous, a few long hairs near the base of the adaxial surface. Panicles terminal, with (4)10-30 racemosely arranged branches; branches 1.2-11.5 cm, divergent; branch axes 0.5-1.1 mm wide, winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 1.8-2.8 mm long, 1.1-1.5 mm wide, paired, appressed to the branch axes, elliptic to slightly obovate, stramineous (rarely purple). Lower glumes absent; upper glumes and lower lemmas 3-veined, margins pilose; upper florets stramineous. Caryopses 1.2-1.7 mm, white. 2n = 40.

Habitat

Disturbed areas, agricultural fields, roadsides, footpaths, grasslands, shrublands, wetlands, humid forests

Comments

Seeds dispersed by wind and water.

Control Methods

• Manual: Small populations of <i>P. urvillei</i> can be cut out, making sure to remove rhizomes; grazing over 2 years may reduce cover by 15%. Can follow slashing by herbicide treatment.
• Chemical: Grass selective herbicides after slashing followed up by fluazifop-P + wetting agent for seedlings. Other choices include: hexazinone and bromacil, glyphosate, 2,2-DPA (dalapon) plus paraquat sprayed three times at 10-day intervals, imazapyr, formulation of mesotrione, terbuthylazine and S-metolachlor or a combination of trifluralin and atrazine.
• Biological: Triple-pathogen bioherbicide system containing Drechslera gigantea, Exserohilum longirostratum and E. rostratum [Setosphaeria rostrata] is effective for the control of grasses

Control Notes

NA

References

IFAS, UF. 2017. Assessment of Non-Native Plants in Florida's Natural Areas. Paspalum urvillei. https://assessment.ifas.ufl.edu/assessments/paspalum-urvillei-paspalum-larranagai/ Accessed April 3, 2022.

CABI. 2017. Invasive Species Compendium. Paspalum urvillei. https://www.cabi.org/isc/datasheet/109621 Accessed on April 3, 2022.

Boufford, D. E. Fumaria. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 22+ vols. New York and Oxford. Vol. 25 http://floranorthamerica.org/Paspalum_urvillei. Accessed [3 August 2022].