Use silicone caulking to glue blocks of wood to the granite wall. Where you apply the blocks, the wall must be wire brushed clean and washed. Screw your trellis to the blocks. While the silicone is curing, you must keep the blocks supported, so they don't slide down.
I would also consider making wood hooks that go over the top of the wall for support...2x4 that are bolted together.
Drilling granite would be futile! The drill would need to be water/oil cooled...
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