Gardening and Horticulture - Whiskey Barrel Decorating

I have one of those 2' or 2-1/2' diameter whiskey barrels with the plastic insert that's about a foot deep and used for plantings. Up to this point it's only been collecting water when it rains and it's about time I get the thing set up with flowers of some kind. Can anyone help me with what should be the various layers that I should be putting in the barrel. Choice of flowers? If I load it with top soil for planting, will everything get waterlogged when it rains? There are no drainage holes in the plastic insert. Should I be putting a few small holes in it? Any advice would be greatly appreciated.

Not the pro around here, but it would depend on what kind of plants you "want". ;) The plastic in there is for water gardening. So...if you want to have water plants, this would be good to keep the plastic in there with no holes. Water plants would be like water hyacinth, fairy moss, water lettuce, duckweed and waterlily. I am not so sure about how to plant regular plants and/or flowers in there, but I do know it will need holes in the plastic for good drainage reasons.