Well, it does mean purple, but Japanese has many, many homonyms, so it could also mean wisteria.

I found two references to that. One says that murasaki is the word for wisteria (which is frequently purple.) The other says: "The name Murasaki may derive from that of a major figure in her novel, The Tale of Genji, or from its meaning of “purple,” a pun on the Fuji of fujiwara, which means “wisteria”"

There might be different names for different types/colors of wisteria as well.