It is with great embarassment that I report my own precious Daubenton’s kale in the US is dead.
It didn’t live a whole three days. Day two of life in the greenhouse, in a comfy new pot, proved to be too stressful apparently, as its tiny leaves, accept for the tender growing tip, shriveled up to a crisp. Even that died quickly after I brought it into part shade.
Obviously, I was at fault to have taken a new plant, fresh from shipping, and stick it in to a greenhouse in full sun. That is a fact. But at the same time any other plant should have been able to revive once in a less stressful environment, as the new leaves just emerging were not harmed. Obviously the plant is not very hardy.
I wonder how it would have faired through cold with resilience like that. I had already planned to keep it in the greenhouse because my area is too cold to keep it outside. But I question now if it could stand winter in even an unheated greenhouse in my area. (Update: Tried to take one through the winter in an unheated greenhouse. It died)
My Mother, hearing how popular the plant is, searched for it herself and landed one from a friend, who had gotten it from a friend. This one is even grafted. Hers she has just kept transplanting into bigger and bigger pots, kept it in a very gentle morning light. But if she has something I don’t, it’s enough for her.
[Note: It died. It froze actually. Even protected zone 5 temps aren’t enough to keep it happy. My neighbor, who has a very protected yard, that is easily a zone higher than us (although in mild winters she has succesfully overwintered plants hardy to zone 8) also lost a Kosmic kale. If you get it, don’t expect anything rugged.]
Snub it and move on to more promising genetics. Why shouldn’t I when I’ve discovered I have, after a particularly cold winter, resprouting luxuriously in the same greenhouse the Kosmic kale died in, a perennial kale?
Sutherland, a variety of kale grown from seed, often can regrow perennial if you hit on the right genetics. After growing through a very harsh winter (in an unheated greenhouse, so there was wind protection, but little protection from ambient temperature, which went well into the -20 degrees farenheit) then leafing out luxuriously all through the spring and summer with 100 + temps any day the sun was out, the smallest flowering that produced no seeds, I have no doubt it is indeed perennial.

So my road to the Holy grail so far has been bumpy, but I’m not out of the game yet.