Thanks for the clarification, Caroline. So you'd be looking for plants that can be depended on to bloom early in the first season from seed, that aren't annuals?
Well, I dunno... gotta say this is very much the usage that annuals are perfect for. The various tender perennial plants we buy for bedding out fit the bill too, of course.
DH has grown
Gazania (tender S. African perennials) from seed and has them bloom okay.
Pelargonium too, of course (but you already knew that.
)
Dahlia from seed?
I find it hard to run with this idea since it's pretty far from my usual
modus operandi.
It seems more rewarding to me to just grow more perennials - they can't necessarily be counted on to bloom in the first season but the effort will be rewarded with years of performance... and there's such a vast number of species that are hardy and uncommon and interesting.