So many orders on the TP and its Account Bound...
Bjarni in Hangrammr Climb does have them in bulk. As well as the recipe for Bjarni's Celery Snack.
I'll second kookamooka, Paenula Drakecatcher does not sell them.
Plus, Milton Book is in a 25+ level area and you need to finish his heart quest. Not possible for my poor lvl 14 toon. My last hope for celery is Bjarni. Why the heck is it so hard to get celery?
Paenula Drakecatcher doesn't sell these... :(
Can be bought in bulk (25 per bag) from either Bjarni (Karma Vendor) in Hangrammr Climb just southwest from Taigan Groves in Wayfarer Foothills; Milton Book (Karma) in Cornucopian Fields just north of the Lion's Arch entrance in Gendarran Fields; or Paenula Drakecatcher (Karma) in Charr's Triumph just southeast of Barradin's Vault in the Plains of Ashford.