I am making a dummy cake for my County Fair. I covered the base with royal icing and let dry. I have tried, royal icing, hot glue and E6000 to attach the vines vertically and they just wont adhere. I have to have this done soon. Any ideas, please, please please

Im not sure what your "red" vines are made of? If they are the red vine candy whips, you might try to stick spaghetti or wire through them and then into the cake.

Sorry I wasn't clear. They are licorice red vines,only these are green apple flavored. I want them to look like flower stems around the base of of the cake.

Have you tried melted white (or tinted green) chocolate as glue?

No I haven't, but I sure will try that!!! Do you think I should refrost the dummy cake also? Some of the icing I put on has peeled and flaked off when I took all the licorice stems off.

I don't have any experience with royal icing on a dummy, but I would think that you'll do what's necessary to make the "cake" look its best. Maybe you can try to repair the damaged spots if you can make them smooth enough. If that doesn't work, then re-ice.