hardy annuals for very little space/soil

Any of the small rock plant types - saxifrage, drab, alpine dianthus...

i have quite a few perennial alpines in pots (sedums, auriculas, bulbs etc) but i'm really after annuals that i can just scatter the seed alongside my front wall and edge of my house wall* that will bring me some colour. alpines are rather small and low-growing and where I live (terraced house) there's no front garden/drive to speak of. also, they would need more effort to grow as they'd have to raised in pots first, and planted out later.

*there's a pernicious creeping weed that grows there instead which i really hate and no matter how many times i keep pulling it up, it always comes back year after year!

You can sow seed of alpines direct into the ground - how do you think they grow in cracks and crevices on hillsides? Just scatter the seed and sweep into cracks. You'll probably need to control the creeping weed though...

alyssium, candy tuft, lobelia [the bluey one] virginia stock, all annuals and grow in the cracks in paths in my garden

In a fairly light soil corydalis lutea might be happy and if it is it will self seed. Ivy leaved toadflax is great in that situation when happy but I've never seen any seed for sale.

thanks for that SBG and MG. I shall see whether I can get some cheap seed! Do you think it's best to sow when the weather's warmer or sow now?

Personally I wouldn't sow for at least a month...