Possible Clues:

• A blooming double century with a single A
• Garden shrub
• Tropical shrub two aircraftmen observed way back
• Bill doubled turnover for excellent ornamental tree
• A state spies on plant
• Locust tree the false one
• It makes an accountant somewhat prickly to join American intelligence
• Savanna shrub
• This may blooming well turn first-rate for a couple of accountants (6)
• Wattle that grows very well, coming up on two bills