are buttercups toxic to bees?

Asked May 19, 2019, 4:57 PM EDT

Are buttercups toxic to bees? creeping buttercups have invaded my property and I don't use any pesticides. I have a wild bee colony in a cedar tree at the back of my small acreage and lots of bumblebees visit my various gardens. I have let the buttercups go and they are blooming where I have not cut them down....now I am worried that I may be harming my bees. I can mechanically chop down the buttercup flowers though nothing will rid me of the plants as they are everywhere, have taken over my garden and lawn and are in my forest as well. :( I was thinking the blossoms were good for the bees but am getting a different impression on line.

Columbia County Oregon bees buttercups

1 Response

Thank you for your question. Since there are several species of "buttercup" flowers, which are pictured in the following article, and named "ranunculus:" https://www.pnwflowers.com/browse/family/common/buttercup?page=2 I just want to make sure that you have "creeping buttercup" (ranunculus repens) discussed here: https://www.kingcounty.gov/services/environment/animals-and-plants/noxious-weeds/weed-identification... rather than the ranunculus occidentalis, pictured below. Both types of ranunculus are attractive to bees, and the an Alaska Extension publication says this:

"The poisonous compound protoanemonin is released in the sap of creeping buttercup. Protoanemonin can kill grazing animals if ingested. Geese and other birds readily eat the leaves and seeds of buttercup... The flowers are visited by honey bees, butterflies, moths, and beetles for pollen or nectar. Creeping buttercup is a known host for many microorganisms, viruses, insects, and nematodes ."

So, it is the sap that is toxic, and, since the bees consume only nectar and pollen, they are not negatively impacted by the plants' toxic chemical. There are not a lot of control mechanisms available for creeping buttercup, as indicated here:
"Creeping buttercup prefers moist soils and is frequently found in moist meadows, in lawns, and along ditch banks. It spreads by seeds and, similar to strawberry plants, by stolons (surface stems) that root at the nodes. If hand pulling is used for control of creeping buttercup, all of the rooted branches must be tracked down and removed; otherwise, the plant may reestablish from stem fragments. Improving soil drainage will make areas less desirable to the plant." (https://s3.wp.wsu.edu/uploads/sites/2054/2014/04/Invasive-Plant-Treatment-Guide-US-Forest-Service.pd...)

Hope this is helpful. Good luck!