No, you did all you could. FWIW, on a large stream restoration project I'm involved with, we just had hundreds of various bare-root woodland species installed exactly as you described. And of course, it's a lot colder up here already. So.......what do you do? Hope for the best, basically, If no snow arrives, that is what would most concern me up here. Where you are, I'd imagine snow cover is a much less certain thing. But then again, you won't see the fridgid cold we'll likely get either.

Just bury the crowns with a small amouont of soil-just enough to cover them up and hold them down. A lot of ours have erosion mat over them too, which I believe to be helpful for our conditions.

+oM

What Tom said, but I'd suggest adding a 2-3" layer of organic mulch to help stabilize soil temperature and minimize the chance of frost heave. Remember that air changes temperature more quickly than the soil temperature, so you probably have a while yet before the ground gets really cold.

This seems to be the exact opposite of winter sowing seeds. Whereas you want frost heaving to help the seeds to germinate when winter sowing, you want to avoid it with roots, correct? I wonder if Mother Nature knows this and allows the roots to grow at the right depth to prevent this?

Yes, may be true but there's another factor w/rootstock. The region where the rootstock originates....especially in fall....may not be the same as the one it's being planted in and this was really my problem! The rootstock actually had stems and the stems had new growth, i.e. new leaves growing on it when it arrived. My property has its own micro climate and we had frost the morning after I planted the rootstock! Luckily most of it was hardy stuff like joe pye and coneflowers but I understand that cardinal flowers are a LOT more sensitive. Seeds, conversely germinate in the climate you are going to plant them in (unless of course you're giving them to someone else in another place :) so they generally have an easier time adjusting weather-wise...maybe?

Frost heave can push roots out of the ground - not good for either wintersown seeds, seedlings or fully grown plants. The advantage with winter sowing is the effect the natural temperature fluctuations; these, together with the moisture, can help weaken a heavy seed coat, allowing germination without scarification.

As for the root stock - Where did it come from? If coming from any temperate region, by now I should think the current season's leaves have already done their task and the plant won't miss tremendously any that are lost at this point. I still think you've done the best you can and suggest a layer of mulch to conserve moisture (cardinal flower does like a moist site) and stabilize the soil temperature - for now it will slow down the cooling (if you wonder how much, go sit in a pile of shredded leaves ... you might be surprised at their insulation value). Later on, the mulch will help protect the soil from excessive warming on those inevitable mild and sunny days in winter.

I don't know how your temperatures are, but here in my zone 7 garden we've had just a few nights of 31-32 degrees, with some mild, sunny days, so the soil is cooling very slowly.

If you feel it necessary, and can find some way of rigging up a sort of cold frame to further slow the cooling of the soil by providing cover at night but exposing to the air during the day, that might help to harden off these plants more gently, but they will have to harden off and fend for themselves eventually.

This post was edited by agardenstateof_mind on Mon, Nov 4, 13 at 0:06