Yes, well, that's a 'how long is a bit of string' question nejaan. You can grow absolutley anything in a pot provided it is of the right size and you are willing to do everything for the plant that it would do for itself in the ground. We have 400 odd (probably in both senses of the word) pots in our garden, from 6'' across to three or four feet - and we never, ever go away in the summer because every pot needs attention every day. Ok, you don't ned to be as besotted and silly as I am, but pots do take alot of attention - depending what you grow in them They need weeding, even with gravel on top, as they cannot cope with competition as there is far less soil available to each plant than would be in beds, watering is an art in itself as no two have the same needs. Advantages are that, at least with somewhat smaller ones, you can move them around as each thing comes into its best. Our daffodil pots are now beside the shed till next spring. Having said you can grow anything in a pot and you can, some things are easier than others. Wild life plants are often natives and tend on the whole not to be as happy in pots as other things. We have small (grown that way, not pruned) buddlea, which the bees/butterflies love, hostas which they lve for the flowers, oregans, mints, many small shrubs and grasses, trees - which may be more than you want - not everyone wants a 12 foor oak tree in a pot - small acers, bamboos, (not not native, but I like them), dicentras, sweet peas, peas, beans, other veggies, herbs, foxgloves are surprisingly happy in a pot, all summer bedding can be grown there, iris's, especially the little ones, all spring bulbs etc. There are some excellent boosk about container growing, try your library and see what they have? Take a look around your area and see what is growing well, ask the gardener what it is, whether it is a perrennial (stays more or less as it is, comes back each year) herbaceous, (dies back but returns each year) annual (needs replaving each year) bulb, most can stay where they are - including lilies which are very happy in pots. I could go on, but won't or I will wear your eyes out!!