if you want something decorative and edible, silverbeet "bright lights" grows well for us in tyres and keeps looking good all year round. Beetroot and curly lettuces can also be pretty and carrots have nice foliage. Basil will look nice especially if you choose coloured varieties such as dark opal. I think Yates sells a mixed basil seed. Its a good companion for your tomatoes both in the garden and in the pot. It attracts bees and repels flies. Herbs would be way up on my list as they mostly like sun and warmth and are useful and attractive. Some herbs worthy of consideration would be marjoram, oregano and thyme, all cascade, love warmth and are available in several leaf colours. Thyme comes in different flavours too like lemon thyme and pizza thyme. Curry plant will like the sun, smells fantastic and has pretty silver foliage. Rosemary looks great all year round and you can choose from upright or prostrate, blue flowers or white or pink. Lovage is a herb not many people grow but its fantastic, some people call it "maggi herb" as it tastes sort of like vegetable stock - mixture of parsley, celery and a dash of je ne sais quoi. If your tyres retain moisture well you can grow mints and horseradish and parsley, all of these it is a good idea to confine anyway as they are invasive. If you get migraines, feverfew is for you, if not pyrethrum. Both repel insect nasties. As far as flowers, apart from those mentioned already, convulvulus mauritanica has gorgeous blue/purple flowers and is tough enough that councils use it. Convulvulus cneorum also, white flowers with pink veins and silvery leaves. Cosmos and stocks are good pickables and easy to grow. The smaller cistuses look good all year and smell nice. If you have a not-dry spot, daphne will flower for you at a time of year when virtually nothing else does and there is a prostrate form but you may have to look hard to find one. There are low growing sweetpeas that you don't stake that will cascade for you and be good for picking. They are normally sold under the name "Bijou". Felicia has sky blue flowers and will form a low mound cascading over. Osteospermum is easy to grow and available in some great colours, "buttermilk" is a very pretty soft cream-yellow, there is also a cool terracotta coloured one. Right, I'll stop writing a book for you, all of my garden centre training came to the fore then. You might need a few more tyres... best of luck