Q: We have a 20 year old Dwarf Alberta Spruce that is not dwarf anymore. It is approx. 8 feet tall.
Can we prune it and bring it back to 5 feet or so? If we can, how do we go about it and when is the best time to so?
We live in the Toronto, Canada area.
You will most likely be pruning down to non-productive tissue, in which case the plant will not regrow. It will look terrible just about no matter how you go about the pruning anyway.
And, since, the typical growth rate of a dwarf Alberta spruce is only about 2" per year, it would take a looonng time, maybe never, before any regrowth that might occur would hide the severity of the pruning.
If you decide to prune it anyway, springtime (just before the growth season starts) would be the time. This way, any regrowth would occur shortly after the pruning is done, which will begin the "hiding" process sooner.