Hardening Young Camellias for Winter
For background on this you could look at this thread:
I'm in New York City, zone 7b. I have a number of young camellias (sasanqua.. don't know the variety) which I started as cuttings in summer 2011 so this will be their third winter. The plants are 8 to 12 inches tall... so still pretty small and delicate. Most of them have leaf buds. Last winter they were all in pots which I burried and covered with plastic and micro foam. Last spring I put them in the ground in various locations and there they remain.
Last weekend (november 9) seeing that there was light frost in the forecast for this week I covered them, again with clear plastic and micro foam over an armature. Then this morning I was looking at the Ackerman book and saw that he says to let them harden off for couple weeks before covering but he doesn't specify what kind of temperatures they should be subject to. We've had some nights in the mid 30s. Tonight is forecast to be 30 degrees.
I took the cuttings from a mature plant very near my home so I'm pretty confident they will eventually be able to survive the winters unprotected.
So here are my questions...
How crucial is the hardening process? Is there clear evidence that it makes a difference?
Should I go ahead and uncover them now and if so at what point should they be covered? After a hard freeze (at or below 28)? Before?
How many years should I plan on protecting them in winter?
Also, it has been a really dry fall here so I watered before covering them. I can't undo this now but for future reference was this the right move?
Thanks in advance for any and all advice!