I am still researching my question about junipers. Paradoxically, J. squamata
is originally from central Asia and is said to dislike heat. J. chinensis is
from a large part of China as well as Japan. The type is said to be hardier
than squamata (Zone 4 vs. Zone 5). However, I have never seen any kind of J.
chinensis growing outdoors here.
I don't know if I mentioned it here, but unlike most subtropical and
Mediterranean conifers, Cupressus sempervirens, the Italian cypress, does not
require any rest or dormant period at all, although it is said to be hardy to
-20 C (below 0 F). I leave it outdoors in the fall with my other hardy bonsai,
but in October it goes right in the house. It can spend the winter in the
sunporch if necessary, in the unheated guest room, or under lights. It doesn't
seem to care in the least, except of course under lights it continues to grow.
Go figure.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

, I have never seen any kind of J.
chinensis growing outdoors here.

I don't recall where you garden, but 'Shimpaku' has been growing outside here
in NW Connecticut for well over 15 years.