The Marin Independent-Journal News-Navigator is pretty definitive about how to pronounce plant names.
Pronounced kal-un-KOH-ee, kalanchoe is a little blooming machine that can light up a room with brilliantly colored blossoms encircled by fleshy, glossy, scalloped green leaves.
Dictionary.com lists 4 possible pronounciations. We prefer the 4th one. The one listed above is generally used by florists, while nursery growers usually say “kuh-lan-choh”.
It would be irresponsible not to comment.