New bed

I have spent the last few days making this new flower bed. At the moment it looks scarily large and bare but the reason that I have had to do it is that the border behind was created last year and is already too small. I'm never very good at working out how big plants can get when established. I have already realised the folly of putting a hydrangea near a lavender so I'm deciding which one to keep. It should have a colour scheme of blue/white/purple  so I dont know how the yellow snap dragon got in there. I will have to move it for next year.All plants are grown from seeds or cuttings so, apart from a sore back, it has cost me nowt!