Vampire Rose
The Vampire Rose is one of the many, many deadly plant monsters found in Dungeons & Dragons. In this particular case, Vampire Roses are blood-sucking vine-type roses, which lash out at nearby living creatures to impale them with their thorny branches and exsanguinate them. A starving Vampire Rose is pure white, but the more well-fed they are, the deeper red they turn.
The Vampire Rose debuted in the module B3: Palace of the Silver Princess for Basic Dungeons & Dragons, as the... "Jupiter Blood Sucker". Yeah, Tom Moldvay saved this one. Its most recent appearance was in Dungeon Magazine #195 for Dungeons & Dragons 4th Edition.
Ravenloft is home to the all but identical plant monster called the Bloodrose.