grapes: sweet sap from branches

Asked May 31, 2014, 5:11 PM EDT

Hello grape experts,

My mother lives in the Netherlands and is having trouble with a grape plant. She has contacted specialists and grape growers there but no one knows how to help her. I'm hoping the description might sound familiar to someone at MSU Extension.

Her 12-year-old grape vine, "Glorie van Boskoop," is dropping a sweet syruppy sap from the branches. It's sticky and ants etc. like it. The leaves and the young grape bunches look healthy. The grape plant is outside next to the patio and grows up under a glass-covered pergola. My mother would really like to save and keep the grape vine. It produces a lot of delicious purple grapes each year and it was planted by my father who has passed away.

If you have an idea of what this might be or if there is anything you could suggest, it would be greatly appreciated.

Many thanks for your time.

Washtenaw County Michigan grapes viticulture

1 Response

Dear Carol,

For sap to flow from the branches, there must be some wound present, either from pruning or perhaps some insect injury. Sometimes bleeding could occur up to a week from a wound. I don't believe it is harmful to the vine. Where in the Netherlands does your mom live? I am currently in the Netherlands. If it happens to be close by, I might be able to take a look at it. you can email me at : Very best wishes,