If you can get them through the winter you should be in great shape, it's the winter that will be your problem.

IMO foxgloves that are too big and healthy often have more trouble making it through the winter (unless they are well protected)... the lush growth really takes a beating and ends up rotting out in the center.
sooooo, I wouldn't fertilize them, especially if they already look healthy. You don't want them getting too big. Also Camelot is a cultivar that will bloom it's first year from seed, if the plants are pushed now with fertilizer there's a good chance you'll have beautiful bloom stalks ready to open the week after they get killed by a hard freeze.

I start Foxglove from seed every year, but I don't always get a good stand of them because sometimes they don't survive the winter well. I get excellent growth on the seedlings, but then they are a half rotted mess by Spring. This is not because they aren't sufficiently hardy, but because the crowns appear to rot easily over our wet winters.

So now I try to plant them in a bed that has excellent drainage; no mulch, leaves, extra watering, or snow/ice pooled near the crown of the plants over the winter; also you might try planting them on a small hill to ensure the crown is slightly elevated. Sun doesn't seem to be as much of an issue because my Foxglove has done quite well with only a few hours of sun.

This pic is from 2 years ago, I had a couple amazing patches that Spring, so it's worth trying each year. :) This is a mix of Excelsior hybrids and Camelot cream -
{{gwi:234565}}

ha ha ruthy ...

i would not fertilize in what will be September .. by the time it gets into the soil ... in MI ...

frankly.. you would have 6 weeks before the first potential freeze.. and in MI ..... we want things slowing down and going to sleep.. not all hyped up on steroids.. like some baseball player .. lol ...

if there is too much lush green.. vegetated growth .... at frost/freeze.. things can rot.. and it might not rot until spring ...

you got a bunch.. try it both ways... whats to lose ...

anyway ... i bet you have pretty decent soil.. so why the juice????

ken

feh - stick them in the ground - foxgloves do what foxgloves do - which is slowly build up strength and roots and only then will they go into flowering mode. Sometimes, if I sow later than usual (like around now) I will get little seedlings of 2 inches or so to put out over winter and it will continue to put out vegetative growth all the following year, only flowering in year 3. Growing in little modules shouldn't stress them too much because they will grow away happily once planted in friable soil. The Camelots are fairly perennial so yep, make sure you have reasonable drainage, don't bother with fert. (waste of money ever on foxgloves) and away you go. A really cold winter just makes them grow more slowly - they don't ever actually seem to die.
You might want to have a look at some of the sterile, but very perennial, long flowering hybrids coming out these days (Pippa, Polly, isoplexis intergenerics) - a 4month flowering season, no kidding.

Thanks everyone for the input. I've grown quite a few foxgloves, but have never planted them this late. I have a ton of them, so if even half make it, I'd be thrilled. I'll probably forgo the fertilizer, unless I try in on a few for experimenting's sake.

Campanula, I grew Polkadot Princess in 2011, so they bloomed in 2012 and again this year. Their first blooms of 2012 were decent...the spires weren't as tall as excelsior, but they still looked nice. The later blooms were much shorter, and didn't do much for me where they were planted.

This year, even their first blooms were much shorter. For where I want to grow digitalis, they don't work, and most have already been yanked. I'll start excelsior seeds this winter, but am thrilled to have a bunch of these Camelots and Apricots to (hopefully) look forward to next spring.

unless I try in on a few for experimenting's sake.

==>>> DO IT!!! ...

make a real experiment over it..

give a couple a teaspoon full ..

a few other a tablespoon ..

and a few other a handful ...

and if you have any time release.. dose a few others with that ...

THIS IS HOW I LEARNED ... back before www ...

you said you have so many ... why not.. just mark them somehow ... so you can report back...

but i would bet a nickle.. they will all live.. since you have many for cheap ...

had you paid $100 for one... one speck of fert would kill it.. if it didnt commit suicide on the way home.. lol ...

ken