Tribulus cistoides

Common Name: burrnut

Family: Zygophyllaceae

Common Synonyms: none

USDA Hardiness Zone: 9a-11

Growth Habit: Perennial herb

Origin: East Africa, Madagascar, Mascarene Islands

FISC Category: 2

FDACS Listed Noxious Weed: No

Introduction Date: Mid 1940s

IFAS Assessment:

• North: CAUTION
• Central: CAUTION
• South: CAUTION

Description

Perennial (sometimes annual) herb, with many-branched trailing stems to 1 m long or longer. Tap root woody, stems often slightly woody at base, tips erect, younger stems covered with silky hairs. Leaves opposite, to 10 cm long, even-pinnate. Leaflets in 5-8 pairs, elliptic or oblong, to 2.8 cm long and 1.2 cm wide, covered with silky hairs, margins entire, bases rounded, tips bluntly pointed. Terminal leaflet pair spine tipped. Stipules linear, to 0.7 cm long. Flowers showy, solitary in leaf axils, on long, hairy stalks 2 to 3 cm long, sepals 5, lance shaped, petals 5, bright yellow, rounded, to 2.5 cm long. Fruit a hard spiny capsule, burr-like, to 1.5 cm across, splitting into 4 or 5 segments, each of which has two sharp spines to 8 mm long and contains one or more seeds.

Habitat

Dunes and coastal strands, sandy openings of ruderal areas and pinelands

Comments

Spiny nutlets are animal and human dispersed.

Control Methods

• Manual: Manual pulling. Mowing is not effective due to the prostrate growth habit.
• Chemical: Glyphosate and dicamba have been used with excellent results. 2,4-D also shows good results. A 1-2% solution of each of these with surfactant is recommended (IFAS) or foliar with 5% triclopyr ester.
• Biological: NA

Control Notes

NA

References

Dave's Garden. 2014. PlantFiles: Burrnut, Tribulus cistoides. http://davesgarden.com/guides/pf/go/103210/. Accessed on June 23, 2014.

Langeland, K.A., H.M. Cherry, C.M. McCormick, K.C. Burks. 2008. Identification and Biology of Non-Native Plants in Florida's Natural Areas-Second Edition. IFAS Publication SP 257. University of Florida, Gainesville, Florida.