Hello Pat,
Since the HP FLEX does not support pvlans the HP blades will be consider promiscuous ports having access to all VMs and hosts on N5k. The best solution is to use a different vlan/subnet for the HP blades.
I developed a vlan-hopping solution a while back but hesitate using it since troubleshooting may be confusing for someone not familiar with the design.
pVLAN hopping for UCS
Matthew