Possible Clues:

• Locust tree the false one
• A state spies on plant
• What'll we hear?
• It takes twice a century for it to start to grow
• On both accounts, I get a plant that likes sun
• Australian tree
• It makes an accountant somewhat prickly to join American intelligence
• Beginning to amble about, spies a source of gum arabic
• Yellow-flowering shrub
• Having mechanical sex with accountants, raised plant