I had mine go away after i finished the first SB quest.
or was it the 2nd? I remember I spazzed asking why it was still there, then a couple minutes later it went away and i had a system message in chat saying i had proven myself blah blah.

I had a lot of time logged also, way more than needed, I had let my account stay logged on while working on homework during my summer semester classes etc. but over 200 hours i heard is enough.

so the sprout goes away at SB now!