Lighthoof: Weed of the Week: Creeping Buttercup

As spring slowly creeps over the northern hemisphere, it’s time to start thinking about pasture management. This week, our friends at Lighthoof introduce us to buttercup, a toxic weed.

Buttercup, famous for determining whether someone likes butter by casting a yellow glow when held to one’s chin, is on the list of weeds that are toxic to horses.

Fortunately, quite a large amount has to be consumed before severe toxicity occurs and it is quite bitter and unpleasant to eat. However, buttercup can be quite prevalent in overgrazed pastures. Without healthy grass to eat, some horses might be tempted to try is out of desperation, and in rare cases some even develop a craving for it.

Buttercup is characterized by small bright yellow flowers with five petals each. It grows to about 12” talk on long creeping stems with toothy leaves. It does well in poorly drained soil and can grow in shade or sunlight.

The entire live plant is toxic but the toxin loses potency once cut or dried in hay. Symptoms include salivation and blisters in the mouth or intestine. It can cause colic, diarrhea, and other gastric issues. If you suspect your horse is consuming buttercup in her field or is displaying these symptoms, contact your vet and explain that she may have been eating buttercup.

It is very hard to get rid of due to quick vegetative regrowth and a long-living seed bank. Mowing it will have no effect or increase its vigor. To battle buttercup without chemicals, outcompeting it with a healthy grass crop, maintaining good soil drainage, and applying lime can help since it prefers damp, acidic soil.

You can dig out small sections, but be careful not to segment the roots as this can encourage growth. If you’ve got an unhealthy pasture and quite a bit of buttercup, chemical control might be your only real option. The herbicide MCPA has been known to be effective. Spray when plant is blooming and keep horses off the pasture and away from any sprayed areas until long after the product recommended waiting period has been fulfilled.

Once you’ve killed your buttercups, be sure to use good pasture management practices to grow a healthy grass crop to replace the buttercup and prevent weeds from returning.

If you aren’t able to remove your buttercup, keep a close eye on your horses, check for mouth blisters regularly, and be sure to avoid turnout if there’s not a healthy forage option, such as grass or hay, to keep your horses from exploring other grazing options – such as that interesting yellow flowery thing…