Hi, Buff,
I grew up on the Piedmont of Virginia which was as cold as here in east TN. Larkspur, poppies and bachelor buttons were our eager repeating annuals that came back decade after decade without our having to do anything to help.
From those decades, the seeds have to be somewhat hardy after they start to grow, or they wouldn't have made it. Here they don't come back as eagerly, but I need to build the population up from the couple of plants' seeds I saved from a fenceline when we first came here.

I don't know about your zone, but in my colder zone, larkspur zooms through the winter without blinking, and our temps go up and down all winter. Don't worry about them.

The only time I had problems was the first season when I planted seeds from a seed pack. Those larkspur were a bit puny and not as thick as I anticipated. However, once they have bloomed, they will self-seed like crazy. If I want larkspur in a spot where they weren't growing, I just cut off a stalk which is forming seeds and take it over to the spot where I want larkspur and shake it. That's it--they do the rest all by themselves. It might be that the first time I planted them, it was too late in the season and that's why they didn't initially take off well. They've had no problems since.

You'll love 'em. They look great next to roses.

Kate

I've had the same experience with them as Ann and Kate - they're tough seedlings that will do fine in ice storms, snow and single digit temps. They also can take the heat, as I planted some at my MIL's house in Natchez, MS and they keep coming back.

I do think they come up too thickly so I thin them. I also stake most of them with thin bamboo stakes. Does anybody get a second bloom by cutting them back? I've never tried that.
Let us know how your sweet peas do. I have not had luck with them here.
Linda

Sweet peas are a problem.
I read the seed catalog and the Red Book how to's. I tried to get a patch of white ones established for a front porch wedding here. Fortunately, the wedding didn't happen, because none of the plants I tried to get started (last minute thing, four month lead time, only time enough for annuals) made blooms when the books/manuals said they would and Sweet Peas led the disappointment steeplechase.
I do know that sweet pea bloom (in sweetpeas gone wild) in these parts start their bloom in May (when I'm looking for lost roses and the sweet pea colors have caught my eyes when rose pink was being watched for.
In New Orleans (much, much warmer) our next door neighbor told me to plant sweet peas in the fall, and then she'd cuss remembering that her late husband would always pull her sweet peas up just before they started blooming so that he could plant his creole tomato starts in that area. (Creole tomatos generally went in Feb-March) I also remember that sugar snap peas would be growing happily along the Gulf Coast one day, then it would be 'hot' and I'd come home from work and the peas looked as if they'd been dead for weeks.
Sweet peas seem to grow best here only when surrounded by abundant other plants (aka weeds.)

You'll have no problem with Larkspurs. You can also try Nigella (my favorites were the Miss Jekyll variety, but all of them are terrific), which is a larkspur cousin. It does tend to reseed thicker and thicker every year. When I lived in east Texas, I had to start sweet peas, larkspur, nigella, etc., by sometime in October for them to do their best. I never had a winter that bothered them, even one when it went down to 10° or 12° with an ice storm. I'm not sure about Tennessee, as it can go down to zero or below pretty easily, and I never tried them in those kinds of temps. But, I bet they'd all work with some kind of mulch after they sprout in the fall, probably have to start them there in September.

--Ron

I always had much better luck with larkspur, sweet peas, lupine, Nemophila if I started them in late fall. Peony poppies and Nigella, I found, were better if started a bit earlier (around late September or early October) because they need warm soil/temperature to germinate but no cold temp ever killed them.

I have planted sweet peas several years in the fall and they have usually done very well until May when they begin to yellow and decline. They have never reseeded here. They are an early spring performer like larkspur and bachelor buttons. I have given many nosegays of fragrant sweet peas to elderly lady friends and they always bury their noses in the bunch and exclaim, "I haven't smelled sweet peas since I was a young girl!" They definitely aren't a "bulletproof" selection for the deep south but have been very satisfactory for the price of a few seed packs and the pleasure the flowers provide! Buff

Buffington, I'd like to smell some sweet peas too. Do you buy a particular variety? Do you get your seeds at the store? Do you seed direct or start them in something else?
Do you grow them on a trellis or what?
Thanks,
Linda

I have ordered antique seeds and bought what I could find at my local nursery.If I remember correctly, the modern seeds performed better. I think they are equally fragrant. I soak the seeds in warm water until they soften and then I just stick them in the ground near my picket fence. They are no problem. They just don't bloom as long as they do in cooler climates. I run some fishing line across and up and down the fence and they twine on it. Good luck, Buff

Try to soak them in a solution of hydrogen peroxide and water (1-10 or 1-8) for half an hour. It speeds up germination. Peroxide does wonder to Lupines, too.

The soaking in H. peroxide referred to sweet peas, not larkspur seeds.

Thanks, Buff and Ceterum. I think it was antique sweet peas I tried with not much luck. I've tried Russell Lupines too with only one good plant resulting, and it behaving as an annual. May try again this fall. I like Texas Bluebonnets and might try the peroxide on them.
Linda

This is interesting because I have much better luck with larkspur if I plant them around New Year's Day. If I plant them in fall, we have a warm snap around Christmas, they come up, try to bloom and disappear but if I wait until a few days post winter solstice, they do fine. Of course, I no longer buy seeds as I do what others stated, pull up a spent blooming plant and place it elsewhere and wait to see it reseed next spring.

Where I buy my seeds, the owner plants his in late fall. His next-door neighbor told me hers never survived, did just like mine.

I told her later that I had found if I put them out between Christmas and New Year's, they did well. She tried it and it worked for her.

Go figure. She lives next door to the successful fall planter and hers did not work by sowing at the same time he did.