Nan
My guess would be that the temps. Sometimes the cold will make Impatiens hug the ground. They really aren't ground cover plants. The Elfin series gets about 8 inches tall more or less. Elfin is what most stores will sell. Give them a chance they may sprout up.

Mr. I, I think you hit it on the head. We're finally getting some higher temps, but more importantly, some humidity along with it and they're all perking up and showing some signs of hope afterall. I planted with a summer wedding to host, so if they don't sing on cue I might have a bride-zilla on my hands. LOL I am still perplexed at such early seed pods though and wondering just how old the seedlings were that I purchased this year. I think my own seedlings and self-sowers may end up saving the day here.
-Nan