Awww, I was going to suggest alyssum! :-) What about pansies in a contrasting or complimentary color AND alyssum?

How about blue daze Evovolus or white Bacopa? The bacopa does well in cool weather, and they both like full sun and they are low growing. Nasturtiums?

Bingo on the pansies - went to the nursery & bought mellow pinky-violet with dark blotch.

No Evolvulus (same as Evovolus ?) at nursery. Had one that died over the winter. But I got a Convolvulus. Love them both.

Bacopa - hadn't thought of that. Or nastursiums. Thank you. Never thought these pretty snaps would be difficult combiners.

Since double snapdragons are so full-on and visually complex my thoughts would go to something plainer as a foil, probably a foliage plant, and maybe a trailer, as a contrast, rather than more flowers. Something like Helichrysum petiolare (probably perennial for you). But maybe under a stronger sun than we get adding yet more colour could work. All a matter of taste.

This post was edited by floral_uk on Tue, Nov 12, 13 at 12:47

Thanks Floral. I agree. You've put your finger on the problem. The pansy I got is called 'Mammoth Pink Berry' and altho I was reluctant about its bloom size, its color, and plainess, seemed to work. If the pot in full bloom looks well I'll share a pic!

Heliychrysum petiolare is a rampant perrenial grower here. Even a rooted cutting takes over. Needs a belligerent companion to keep it in check.

That's a pretty pansy, iris gal...I love that color. I'm also a fan of of the clear hybrids...they serve the purpose of an accent plant beautifully.