From the plants point of view, there is nothing wrong with planting now. I've planted a lot of fall sale plants with very few casualties.

frost equals air temp ... what does it have to do with ground temps ..

the easiest.. simplest.. most bullet proof methods is to plant them ...

you can bury pots.. IF your soil drains .. but the pot itself.. will still complicate it all ...

they can go into the ground.. until ground freeze ... or all winter otherwise ...

does you soil freeze?

ken

The ground definitely freezes here (we had -5F temps last January), but I don't think it will freeze soon. I'm still trying to figure out the timing on this area of New York (Finger Lakes region), but I think the ground will not freeze until late November.

Thanks,
Bellatrix

We're on the other side of Lake Ontario from Rochester and up a bit from Toronto. Late November seems reasonable. You can't imagine how unpleasant (very cold hands) it is to chop through perhaps an inch (by then) of frozen soil and plant spring bulbs in mid December.

As said elsewhere, I find no problem in overwintering perennials, planted in garden soil, in pots outside. Water up to the time of freezing.

Ours do fine, frozen solid, in a protected place (e.g. against a wall) covered by the snow.

As per Ken (not that he referred to this exactly), the soil in the pots should be about the same as the soil in the garden.

As a general rule, here at least, plants grown in growers' peat-perlite mix should have most of it pulled off before being planted in the garden. Otherwise, here at least, the peat-perlite mix will freeze, in winter, at a different rate to the garden soil around the plant and the plant is likely to be killed.

I'd advise to plant now and mulch well around them but not over the crown. I have lost plants in pots, often because they don't drain well, but haven't lost ones I've planted to anything but voles, and that's a problem year round. The mulch helps prevent multiple freeze-thaw cycles, so the plants won't heave.

I live in Plattsburgh NY and plant in the fall all the time. I have even bought bulbs at Black Friday sales (for a dollar!!) and had them come back!!

Thanks, everyone! They have been planted in the ground, out of the pots. Hopefully, they will get well established before the really cold temperatures arrive.

Now, if I can just figure out how to overwinter my black and blue salvia in this area of New York :). That can be next year's project.

Thanks again,
Bellatrix

If you have a cool indoor area, potted 'Black and Blue' will overwinter. I've kept a pot in my root cellar and others in my little used and unheated (except by solar gain) front foyer. I just have to periodically check moisture levels so that they don't totally dry out. They also survived but didn't look good in the 60-65 degree kitchen by a bright window.

I use three approaches to overwintering perennials in pots.

1. Place in unheated but insulated garage.
2. Dig a hole in a holding area or the empty vegetable garden and plant to top of pot. Mulch well after ground freezes.
3. Take to cool dark room in basement for winter. Once a month water lightly to keep roots hydrated. This is for tender perennials or those where spring blossoms have already set or where a plant blooms on both new and old wood.

Agree with others, the best idea is to plant them before the ground freezes.