Ultimate border edge combos
I have new raised bed which I'm planning and originally I intended to avoid annuals (I'm referring only to border edge plants here) but after researching Creeping Phlox, Verbena etc. I have come to realize that these cannot compete with annuals especially in terms of length of bloom. Besides I have enough to worry about for the first year. Ironically I have a book, Perennial combinations which I got many of my ideas from and they show a few annual groundcover combinations with perennial contrast flowers probably because the two bloom periods do not overlap in most cases. The area I need to cover is only about 50 sq ft.
Anyhow, my plan is to have an area with a deep purple flowered ground cover. I may throw in a few white or red tulips treated as annuals for spring but for summer contrast I have seen small yellow Yarrows (King Edward or Wooley) or yellow Coreopsis used for spots of color within the purple. For the groundcover they show the old standby, Cambridge Blue Lobelia.
I'd also like to have another area with more of a blue flowered groundcover and contrast that with small red flowers like Zonal geraniums.
Anyhow, in keeping with my title, what would be some awesome annual combinations in the deep purple/bright yellow and blue/red. I assume Lobelia would be the best background for both and from what I can tell there are types which are more blue than purple and vice versa. For the contrast flowers I'd prefer types which will not overwhelm the lobelia and just remain as punctuation points for the most part (annuals are fine for these too).