I have started stuff like forgetme not and then planted it in the fall with no problem. I general grow seeds that are a problem for me but these are mostly annuals that I will put outside the following season.

I sowed coreopsis and engelmanii daisy seeds for fall transplant yesterday. I have existing digitalis and rudbeckia triloba seedlings from spring sowing to plug in about September when it gets cooler and wetter.

Many perennials will manage to flower (albeit lightly) next year if planted now.

Sow 1/2 of your seed, keep 1/2 in freezer...see what happens.

August and Fall planting is very accepted down here, and one of the best times to plant, but we don't get the winter of you guys so don't listen to me.

mmmm, I am doing stuff which doers not need vernalisation - rhemannia, foxgloves, hesperis, some delphs. As a last ditch rule of thumb, I try and replicate nature - so seeds which are being shed now get sown, often in situ if I have a lot - aquliegia, martagons, campanulas and meconopsis at present, making little footscrapes in the soil and ensuring the seeds get pressed down well to make a firm connection. If they are going to germinate, they will, and if not now, then after a stratifying winter, they come up in spring. I sow seed willy-nilly, ,most times of the year because I like doing it and don't mind too much if it goes pear-shaped.....and I do try to hang onto my pots for at least a couple of seasons - clems are really slow and then there is hypogeal germination, where there is nothing to see for a season for germination has occured under the surface.
But yep, hedge your bets - sow some now and some autumn to overwinter, and maybe some in spring - there are a number of good databases on the interweb.

There are some perennials that need cold stratification (i.e., winter temperatures) in order for seeds to germinate. If you know the botanical name of the plant, you can look in the Tom Clothier database (see link below) for seed starting information.

Obviously, many plants self-sow--I have Virginia knotweed, Penstemon/beardtongue, black-eyed Susans and others that have self-sowed in my garden beds.

A large percentage of the perennials in my many garden beds were grown from seed via the winter sowing method (see GardenWeb forum of the same name). It's simple, natural and gives you a chance to get your hands in dirt right through the frigid months. As an added bonus, it produces incredibly healthy, hardy plants.

Will this work? Will it only work with certain perennials?

There's a lot of conflicting information available online about seed starting but the Clothier database is the experts' (and my own) Go To source for seed germination information.

Here is a link that might be useful: Tom Clothier Database