easy shrubs, plants, bulbs etc

i need to get some plants for my back garden as its depressing to look at. At the moment its just a patch of grass in bad shape. I am hoping to plant stuff in pots and barrrells as i can't face digging beds (would these be known as raised beds?) What plants would be foolproof? Also if i got a large container eg a wooden box maybe about 4 or 5 feet long, 3 feet wide and maybe 1 deep can i plant a few different things all together in that...