Toxic Parts:
cyanogenic glycosides
Flower Color:
  • flower color
  • flower color
ornamental, woodlands, shrublands, grasslands

Geographical Distribution

Cotoneasters distribution - United States

Related Species


Cotoneaster spp

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Cotoneaster spp are a genus of flowering evergreen shrubs or small trees from the rose family. They are native to Eurasia, but have been cultivated worldwide for their use as ornamentals, and are now considered invasive in many countries, including the United States.

All parts of Cotoneaster spp can contain varying amounts of cyanogenic glycosides, which are toxic if ingested. Although there have been no previous cases of poisoning by this genus of plants in horses, there has been fatal case involving a llama. Horses are susceptible to cyanide poisoning, which is caused by ingestion of cyanogenic glycosides.


  • Cyanosis
  • Dyspnea
  • Tremors
  • Convulsions
  • Irregular Heartbeat
  • Loss Of Consciousness
  • Difficulty Breathing
  • Death


PHYSICAL CONTROL: Mechanical methods: Removal by a weed-whacker may be feasible at the seedling stage, but it is imperative to cut plants close to the ground, which risks hitting rocks. If herbicide is not applied, the stump will produce profuse coppice shoots. Effort required to kill the stump can be minimized by timing the initial cut to just after fruit set. This maximizes depletion of stored energy in the root system, thus weakening the plant. If plants are cut after fruit set but before fruit ripening, there is less chance of mature berries falling to ground and creating new plants. Frequent removal of coppice shoots will eventually starve the root, but if the initial cut is not correctly timed, it could take two or three years to effect kill. Stump removal is difficult and labor-intensive because of the tenacious root system.

CHEMICAL CONTROL: A cotoneaster can be killed by cutting down its branches, which, because of their dense zig-zag pattern, is not easy. Cut surfaces of the cambium-phloem layer should be painted with a 25 percent solution of triclopyr (as Garlon 4å¨) herbicide with 75 percent cottonseed or other light cooking oil as surfactant and inert ingredient. Glyphosate (as Roundup Proå¨, 100% solution) may be substituted for triclopyr, but with less certain results. Frilling the bark to expose more phloem adds to the absorptive surface. Herbicide should be applied to cut surfaces immediately after cutting; delay of even a few minutes may reduce or prevent effectiveness.