Posted: 14/04/2012 at 08:17
Emma is right, annual bedding will give you great colour and sowing seeds is the cheapest option by far. Otherwise, have a look at the neighbours gardens for the kinds of things that are thriving. Lavender is a good goer if you have gritty well-drained soil , it doesn't take a deal of looking after and smells great; rosemary likewise. I tried one of those cheap 'bee and butterfly' seed mixes a couple of years ago and it did really well - just scatter on and rake in or you could go for the posher modern meadow mixes. Yank it all out at the end of the season, couldn't be easier!
If your parents live in a place that has quite mild winters you could try hebe's which you can usually buy in packs of 6 from the garden centre, if they're happy, they'll eventually fill out nicely and you can still plant round with annual bedding and a few bulbs until they get big enough.
Good luck, whatever you decide