Lots of perennial seeds don't need chilling to germinate. If you can keep the seedlings somewhat shaded and well watered for a couple of months, you will have flowering-size plants next year (but don't expect full-size for another year). I don't usually direct-sow anything except hardy annuals; I usually pot everything up. You definitely get higher success rates if you pot up the seedlings, compared to direct-sowing. You may find that some seeds will not germinate until early fall. That's just the nature of the beast.

Thanks lilydude. Do you transplant them from the pots to the beds before winter? If not, how/where do you keep them through the winter?

I like to put them into the ground as soon as they are well established in the pots. That gives them time to get established before winter. Or you can keep them in an unheated greenhouse, porch, or cold frame and plant them in Spring. But then you're dealing with cold, wet soil. The soil conditions in late summer/early fall are perfect.

Kill your slugs. They will annihilate the young plants.