How do stop ground hogs from eating tulips?

I have never actually heard of this before but then we can't grow tulips here, too warm. However I have heard of people having trouble with beaver in the gardens and the only thing I know of to keep them out is chicken wire fencing, sunk down into the dirt about 12 inches and then 18-24 inches above the soil.
I don't know if this is the solution for you. Do ground hogs tunnel like moles?
I have a univ near me that has a agriculture/horticulture program and they are a font of info for local problems. Maybe you could contact the closest one to you and ask for info.

The cheeky answere is to say 'move to Europe' but I don't suppose that this would be helpful.
I have heard of people using fine wire mesh to protect bulbs from mice and voles - but I don't know what the teeth of ground hogs are like. I suppose that they would quickly chew through plastic pond baskets?

You might try growing a castor plant nearby...it keeps things like moles away from plants, so maybe it could help here

Another suggestion is to find the holes from their lairs or runs and drop a few seeds of the Castor plant in, the seeds emit something that scares away underground pests

I will answer this as delicately as possible: Be careful to take good aim! Otherwise, if you are of the same mind as I am, take satisfaction in watching the ground hog enjoy his meal. Believe me, the latter suggestion is the only practical solution to this problem. Best Regards!