Black Lotus will be BOE on patch 1.70
According to Eyonix, Black Lotus will be finally made Bind on Equipped in Patch 1.70—the next future patch after Blackwing Lair is released, which means Black Lotus will be now available on Auction House for profit. It will allow Alchemists to make more Flasks. If only the Scholomance Lab requirement was removed, sighs!
Eyonix While I’m not sure of the original reasoning behind the Black Lotus herb being made bind-on-pickup, I do know that this is going to be changed for patch 1.7, which is the patch scheduled to release sometime after the next content patch. If your desire is to sell them for profit, feel free to hang onto them until that time.
Source: Official Forums