It's worth picking up the bloodpetal sprouts you find around Un'Goro just for this quest. The gifts often contain level 45 food and water, as well as superior health and mana potions.

Dadanga is a reference to Legend of Zelda and Zelda: Ocarina of Time (IIRC) of the boss Dodongo.
Many Zelda references in Un'goro Crater :)

This quest is repeatable (i was worrying i'll have to throw away any spare Bloodpetal Sprouts).

actually, Dodongo's have been in tons of Zelda games so far:

The Legend of Zelda
Dodongo first appeared as a boss in Level 2.

The Legend of Zelda: Link's Awakening
Several Dodongos appeared as mini-bosses in the Key Cavern.

The Legend of Zelda: Ocarina of Time
Three types of Dodongos appeared in The Legend of Zelda: Ocarina of Time. All three types are found in Dodongo's Cavern. The first that Link fought are called Baby Dodongos. The second are normal Dodongos. Finally, the third, King Dodongo, is boss of Dodongo's Cavern.

The Legend of Zelda: Majora's Mask

Dodongos in Majora's Mask are cosmetically identical to the normal Ocarina of Time Dodongos. The only real difference is a variation in size. They reside in North Termina Field.

Oracle series
In The Legend of Zelda: Oracle of Ages and The Legend of Zelda: Oracle of Seasons, Dimitri is a friendly Dodongo and an ally to Link.
Also, in The Legend of Zelda: Oracle of Seasons, Dodongo appears as boss in the Snake's Remains.

The Legend of Zelda: Four Swords Adventures
Dodongos appear as bosses atop the Tower of Flames.

The Legend of Zelda: Twilight Princess
Dodongos appear as common enemies in the Eldin Province, first appearing in the Goron Mines. They look somewhat like large geckos, and are best killed by an arrow into their mouths. Unlike some previous incarnations, they are quadrupedal.

The Legend of Zelda: Phantom Hourglass
Dongorongo is a similar enemy that Link fights in the Goron Temple.

(Source: http://zelda.wikia.com http://zelda.wikia.com)

Does not count towards the Loremaster of Kalimdor achievement.

Please note that Add-ons (Such as EveryQuest) and the Wowhead Profiler do not count this quest as completed even if you have done it. This is because it is one of the ~Pick up and hand in with one click~ style quests, or one of the special repeatables which are scattered around the world which don't actually seem to treat themselves as real repeatables. Even if you query the blizzard servers for your completed quests, this quest registers as incomplete.

Maybe this will change in future, but is valid as of the posting date.