The Anxious Sprout is the name given to a bamboo sprout in Pikmin 2. It will be found on Sublevel 5 of the Bulblax Kingdom, it is burried and White Pikmin will be needed to dig it out. It is the number 9 on the List of Pikmin 2 treasures.
Captain Olimar's Journal
"I just realized I completely forgot to put something in my latest expedition report. When carrying fallen creatures or pellets, Pikmin will take them to the Onion of their same color. If a mixed crew of Pikmin are carrying spoils, the color majority dictates the destination. Carry pellets to same-colored Onions to maximize Pikmin seed production."
"A quick-growing plant. Good for garden hobbyists or for a snack. Use it however you see fit!"