Kerria do bloom on old wood, so dying back to the ground is definitely a problem. Mine are along a windy drive in full sun with no die back and I've seen them blooming profusely in Upper MI -- could she have a different cultivar that is less cold tolerant? Winter protection is worth a try.

I have the double flowered kerria. Because of its green stems, it is a great favorite of rabbits, mice, deer, and anything else that browses during the winter or early spring. I go to great lengths to protect it (not from the winter, only the creatures), using netting, wire cages, etc.), and still I get about 60% or more eaten off, which means very few blossoms later on.

I propagated a kerria for my sister (zone 2/3) who has no rabbit/browsing problems, and hers is beautiful, full, and covered with flowers year after year, so I'm thinking the cold may not be the issue for you.

Good luck!

Kate

Just a thought, but what you think is winter die back may be hungry winter browsers instead.

I had the double flowering Kerria and last year it bloomed beautifully. This spring it was nothing but brown dead branches with new growth from the bottom. It is now history as I got tired of it taking over its allocated spot, new shoots just seem to pop up and the fact that in the 10 years I've had, it flower exactly twice. I don't feel they are really hardy in my zone.