This is a cute idea and could be placed out in your garden afterwards as an unusual planter. Car boots and online auctions would be a good place to search for old style metal watering cans and they don't have to be in mint condition to look great. You can leave them as is or sand them down and paint them. Watering can table centrepiece
Watering Can - A gardener’s dream, this vintage, watering can is filled with stems of joyous snap dragons. The vibrant flowers contrast nicely against the weathered tin. Once the flowers perish, the can may be used to water new seedlings in the garden for future occupants.