Unfortunately, even if you had a boatload of negative energy, you still couldn't make a useful wormhole from scratch. Your attempts would only result in the creation of a little pocket universe with a wormhole connection to the rest of the universe. If you concentrated a bunch of negative energy in your front yard, all you'd do is make a tiny universe containing your house with a wormhole in the front yard connecting to the external universe. To make a useful wormhole connecting distant places, you'd need to start with a pre-existing submicroscopic wormhole that does this. You'd then use your negative energy to enlarge this tiny wormhole. If submicroscopic wormholes in the "quantum spacetime foam" don't exist, you're SOL. Source: The Physics of Stargates --Parallel Universes, Time Travel, and the Enigma of Wormhole Physics by Enrico Rodrigo
