Answer: Most perennials will only bloom for about a month at a time at the very most, so your spring to fall wish precludes them. (The various creeping thymes, however, are fabulous perennial plants you might wish to consider nonetheless. In addition, a number of perennials will have foliage hugging the ground but blooms at a height of say ten to twelve inches. Allowing these would expand the selection also, but still none would bloom all season. )
All summer blooming annuals might include: sweet alyssum, creeping zinnia, or portulaca. If you are willing to extend the height to twelve or even eight inches your choices would expand greatly. Good luck with your planting!
Q&A Library Searching Tips