Bur Buttercup

Identification & Biology
Alias' : Curveseed Butterwort, Little Bur, Testiculate Buttercup
Latin Name : Ranunculus testiculatus
Category : Terrestrial Plants
Description :
  • Low growing annual with a short taproot
  • Often growing in dense mats, with individual plants reaching up to 5-8 cm tall
  • Flowers are bright yellow and very small with 5 petals that each develop into a seed-containing bur when the plant is mature
  • Burs are around 1 cm long and turn dry and brown at the end of the season
  • Leaves are pointed, covered in fine white hairs and branched in a finger-like pattern that resembles a bird’s foot


Bur buttercup requires the cooler temperatures of early spring to germinate. Small yellow flowers bloom in April-May for approximately 3-4 weeks. Flowers form into fruits called ‘burs’ in late spring. Plants dry out and turn brown by early summer. The sharp spines of burs can lodge in shoes, animals, clothing and even bicycle tires, enabling dispersal of the plant.

The small yellow flowers and spiny burs of bur buttercup can be confused with those of puncturevine (Tribulus terrestris), another invasive plant. Bur buttercup can be differentiated by its finger-like leaves at the base of the stalk, compared to puncturevine’s rounded leaflets. Bur buttercup is also very tiny with upright stalks, while puncturevine has horizontal creeping stems that can grow up to 1.5 m long.  

Look Alikes

Bur buttercup grows well in sunny and dry conditions on open disturbed sites with sandy or gravelly soils. This can include campgrounds, parking lots, gardens, pastures, roadsides and lawns. Native to southeastern Europe and southwestern Asia, bur buttercup is now found across arid and semi-arid regions of western North America.

Impact & Risks
  • Toxic to livestock when ingested – causes blistering of mucous membranes
  • Lethal to sheep when only a small amount is consumed
  • Horses and cows may show symptoms of emaciation, diarrhea, weakness and paralysis
  • Can contaminate small grain pastures, causing agricultural loss
Prevention & Mitigation

The most effective way to ensure that your lands do not become infested with bur buttercup is by prevention. Here are some recommendations to prevent invasion on your property:

  • Do not let bur buttercup go to seed
  • Apply a thick mulch or establish ground-cover plants that shade the soil to reduce bur buttercup seed germination
  • Clean burs from animals, clothing and shoes before leaving infested areas
  • Maintain your crops and natural lands in a healthy, vigorous condition to ensure a competitive plant community; competitive perennial grasses and forbs utilize water and nutrients that would otherwise be readily available to bur buttercup
  • Regularly patrol your property for bur buttercup plants and immediately control or remove infestations before seed set
  • Cooperate with adjacent landowners and encourage them to prevent bur buttercup spread
  • Immediately re-vegetate disturbed, bare soils with an ecologically suitable seed mix that provides dense, early colonization to prevent invasive plant establishment
  • Do not move contaminated soil to a new area
Treatment & Disposal
  • Treatment is most effective before plants flower or go to seed
  • Plants can be hand pulled or dug
  • Shallow tillage or hoeing can be used to control small outbreaks
  • Dispose of burs caught on animals or clothing in the garbage
  • Chemical control is an option; before applying herbicides, read the label thoroughly to understand how to use safely and effectively
  • For further information on the selection and application of chemicals to protect your crop, contact Agri Service BC at 1-888-221-7141 or email AgriServiceBC@gov.bc.ca
  • There are no biological controls (natural insect enemies) for bur buttercup at this time
Okanagan Distribution

Priority Level Definitions

Watch For - Poses a significant threat (very high risk) and does NOT presently occur in the region OR is relatively new to the region and is very limited in extent.
High - High risk/impact; limited population with significant potential to spread in the region.
Medium - Medium risk/impact; limited distribution – broader population distribution with potential to spread further in a region.
Low - Low risk/impact; may be widespread or not, may be of concern in specific situations with certain high values – e.g. specific agriculture crops. Some species may be treated primarily with biological control agents.