Hi Emma

I think yellow and purple is a great challenge and bearing in mind much of the colour could come from the green foliage it doesn't need to be garish at all. I would consider herbs (lavender (french) , tansy and purple sage come to mind), aliums, roses, jonquills, crocus tommasinianus, iris reticulata. These plants would provide wonderful textures and scent. I would look at a book on companion gardening and a rose catalogue for lots of ideas. And I shouldn't forget the long flowering violas - none of those ubiquitous pansies! And nasturtians to hang down - endless varieties . And Vegetables - but thats another thought.... I have a plum tree I must go and plant out today!

jay jay