A few years back when I started growing bamboos (which was in the 2007-2008 timeframe), I took a lot of care to protect them during the winter. The advice I got was to ensure that the young plants had as many green leaves in the spring as possible, and that meant wrapping small plants to protect them from cold, dry winds, tarping plants to the ground, and even building a temporary greenhouse.
Since the plants are larger now, I have more of them than I know what to do with, and I got tired of looking at ugly plastic sheets in the garden all winter, I've stopped with most of those extreme measures. That's not to say I don't do some things to protect my favorite plants from the coldest weather though.
As you probably know, potted plants are more vulnerable than plants in the ground because the roots are exposed to the extreme air temperatures -- without the relative warmth of the ground, plants in pots are less cold-hardy.
For even the cold-hardy bamboos, a severely frozen rootball could mean rhizome buds that are damaged, reducing the number of shoots and/or rhizomes that the plant can produce. It's even possible for all of the buds to be killed, leaving you with a potted bamboo that never produces more shoots and therefore will eventually die.
So I've been gathering up the potted bamboos in order to give them more protection. The mild start to the winter means that I've been able to put this off until late December, but it's time to get this going.
The biggest pots were all dragged down to the back of the garden, in the spot where the temporary greenhouse was located. (This is also where I intend to build a garden shed "soon" -- if I keep saying it, it is more likely to happen, right?)
Once all of the pots were gathered, I dropped a couple of yards of mulch onto them, covering the pots in a warm mound of chipped wood:
The difficult part was getting the mulch into the voids between the pots in the center of the grouping:
Although this mulching will do nothing to protect the leaves from potentially leaf-killing winds, it should help to ensure that the rhizomes stay alive with all of the buds intact.
Most of the smaller pots were moved under the deck, against the house:
If really cold temperatures are expected for more than a night I will mulch over these pots as well.
I've left some pots on the driveway too. It may sound uncharacteristic of me, but I just don't care about preserving every single pot of bamboo. If some of them don't produce shoots in the spring, it just means less pots to worry about next summer -- I have too many as it is.
I'm still hoping for a relatively mild winter like last year's, but I still have to plan for a cold one. I'm just not as worried about the bamboos as I once was.
Incidentally, my driveway is almost entirely clear of pots now! Six months later than I had hoped, but still good to see.