Yellow Flowers in the Pasture: Safe or Dangerous?

  NEW BRUNSWICK, NJ (June 4, 2012) – The mild temperatures and abundant moisture experienced in New Jersey recently are primarily responsible for the abundance of flowering weeds sprouting up in pastures and paddocks. While buttercups are usually not eaten and dandelions are not toxic at all, horseowners should be aware of a potentially dangerous “look-alike” called catsear. Read on for descriptions of some common harmless yellow flowers and how to tell them apart from those weeds dangerous to horses.

     Most people know that buttercups are toxic to horses; however most horses will only eat them if there is inadequate forage in the pasture and the horses are truly hungry. If your horses have abundant, nutritious grasses also growing in their pastures and/or have free access to hay, do not panic if you see a few of these flowers, depicted in Photos 1 and 2. If they do eat a large amount, buttercups can cause oral irritation and pain.

Dandelions (shown in Photos 3 and 4) are not toxic and actually are fairly nutritious, so if you see your horses helping with dandelion control, it is not cause for concern.

  Catsear is a potentially toxic plant which looks very similar to dandelion (Photos 5, 6 and 7). It has yellow flowers that look like dandelion flowers, but the two plants differ in stem and leaf structure. Some ways to tell catsear apart from dandelion are as follows:

  • Stems: Catsear has several stems with multiple flowers per plant, while dandelions bear a single flower per plant.
  • Leaves: Catsear has soft, hairy, rounded/curved-lobed and darker green leaves compared to dandelion with its hairless, lighter green, course/pointed, deeply serrated leaves.
  • Flower: Underneath the flower, the green leaf-like structures (sepals) cling to the yellow catsear flower. In dandelions, the sepals curl away from the flower.
  • Season: While dandelion blossoms in the early spring, catsear blossoms in the early summer.

     Horses have been known to eat these even if other good forage is available, but a fairly large amount needs to be consumed before toxic effects occur. Catsear is suspected to cause stringhalt, a neurologic problem where the horse will suddenly flex its hind legs in an exaggerated and uncoordinated fashion. The condition caused by catsear is known as Australian stringhalt due to its prevalence in Australia and New Zealand. Stringhalt is also associated with vetch and sweet pea poisoning in horses.

   If you do find large amounts of catsear in a pasture, remove horses from the pasture until the catsear is removed. If the pasture is small, remove the plant by digging it up or spraying it with Roundup®. Be careful with Roundup®, however, as it will kill all other vegetation it touches; follow all label directions. If your pastures are large and/or you have a large catsear infestation, you may need a large herbicide application. The following options can all be used to control catsear:

  • 2,4-D at 2 quarts/acre or
  • Dicamba at 2 to 4 pints/acre or
  • 2,4-D + Dicamba at 1.0 to 1.5 quarts/acre of 2,4-D + 1.0 pint/acre of Dicamba.

     Remember that these broadleaf herbicides will also remove clover. A lower rate of 2,4-D will allow most of the clover to regrow while the addition of Dicamba will reduce it for a few years as well as eliminate the catsear. Read the herbicide labels carefully and follow all instructions. If you need assistance, don’t hesitate to call your local county agriculture and resource management agent. County office contact information can be found at:

     For more information, browse the FAQ section of the Equine Science Center website ( or see the following fact sheets:

Odd Things that Horses Eat
Poisonous Weeds in Horse Pastures
Equine Pasture Management: “A Year-Round Approach”