Answer: Pruning signals new growth in plants, so if you think the worst of your winter weather is over, go ahead and prune. If the temperatures fluctuate, and it's warm enough for plants to grow, any new growth that is produced will be quite frost-tender. A late frost can damage new growth. All this boils down to the fact that you may have to prune off winter damaged shoots in the spring. This has been an unusual winter in the Pacific Northwest, but generally the coldest weather is gone by the end of February. If the pyrmidalis were mine, I'd wait another month before pruning.
When you prune, try to maintain the integrity of the pyramidal growth habit. If you cut the tops straight across (as many people do), the top will become a saucer, collecting snow. This added weight can bend individual branches down, sometime snapping them off and ruining the appearance of the plants.
Q&A Library Searching Tips