Possible Clues:

• Flower in a container like this
• Area like this contains container for plant
• Plant with prickly leaves often featured in Corinthian architecture
• American regularly shouts about hypocrisy for Bush?
• A container like this is needed for prickly plant
• Widely grown Mediterranean plant with spiny leaves
• Plant with spiny leaves
• Plant needs a container like this
• Herbaceous shrub in a container like that
• Like this a tin will have spikes