Wyrmtail
Only found in Dustwallow Marsh, this plant is rumored to have been planted by the Black Dragonflight that surrounded Onyxia’s lair in the south. To spot wyrmtail look for thick green vines wrapped around a faintly glowing green core that pulsates slightly - similar to a heartbeat. This pulsing is likely intended to distract passersby, making them easier prey for the black whelplings and others that still inhabit the area of the swamp it grows in.
An invasive species, the native environment of this plant is unknown. When it was brought there it grew wild and in great quantities, pushing back other native flora. Time and necessity have changed that, making wyrmtail harder to find than it once was.
It has a faint magical aura and, when properly picked and prepared, can be used to ease pain and heal minor wounds. Due to this it has become prized by residents of the marsh. After the fall of Theramore it gained even more popularity with some of the remaining Alliance aligned holdouts due to the lack of easily accessible supplies.
Wyrmtail was introduced in a course of tragic and unfortunate events and this plant has come to hold such meaning now. Though practical people will accept offerings of it for the uses it has, to give it as a gift in a floral arrangement is a spiteful gesture. This is a quick way to earn the ire of the one you give it to as such a gesture implies you find them tragic, their presence an unfortunate burden you are struggling to make the best of despite your distaste for them.