Novice fruit tree grower-Zone 6a "winterizing"
Having seen the help you gave to the fig tree question and the moving of the Sour Cherry tree in autumn, I am hoping you can provide me with some very specific guidance.
We live in the north-east, right by the ocean (I mean we can see it...not boasting trying to let you know about wind issues!), in an area that has a moderate, maritime micro-climate. This spring I planted two different varieties of cherry and pear. which are grown in this area. All four trees are doing well so far and I want to keep it that way.
We live in the country, so I have deer fencing loosely draped around the little trees which (pretty much) kept that charming pest away from the delicous buds/bark. The trees are 6-7 feet high and are cross-braced with hosing and wires to keep them straight.
Now that we have had three nights of frost, I have, as most locals suggest, wrapped the trunks in the white plastic "tape" that keeps off rabbits, squirrels, mice etc and also provides protection from our biggest threat, South-West wind splits (from freezing and then very warm sun on tender bark).
So, now that I have done the final weeding of the season, am I supposed to be mulching? before ground-freezing? and, if not now, when? and with what? (I have shredded leaves, pine bark mulch, balsam 'needles', seaweed to choose from).
Thanks in advance!
The major point of mulching in your situation is to prevent ground heaving from freezing and thawing. Therefore, wait until the ground is frozen pretty solidly to mulch in order to keep the ground frozen. Shredded leaves will break down over the winter into early summer and release nutrients gradually. They may tie up a bit of nitrogen while decomposing but will return that nitrogen to the soil and air later on. This effect on soil nitrogen can be a problem in some cases but will be to your advantage with trees in the second year from transplanting as too much nitrogen will encourage excessive top growth relative to roots. Pine bark mulch will last a lot longer and so has little nutrient impact. It would be more of a semi-permanent mulch. I would be wary of the acidifying properties of any conifer needles for cherries and pears.