Possible Clues:

• Plant container
• River Po silt finally an aid for gardeners
• Possibly wrote flop - one containing bloomers?
• 'Plant there, but no machinery (9)'
• Something in the garden for pet owl to chew
• Where I might grow river grass?
• Place for growing the best cannabis
• Old Bill's residence shut before predator turns up
• Geranium holder?
• Container for plants