New Zealand Flax Pruning
What is the recommended process to prune the flax?
You mean Phormium, right? These guys require minimal pruning. In late spring remove any dead or damaged leaves all the way to the base. Never "top" a flax as the leaves will never grow back into a point again. Some grow quite large so if your particular species is one of those and it's in the wrong place, it's best to move it to where you won't always battle it. Hope I got the right plant! :)
You have the correct plant. I have seen some pruned with the top 1/3 gone and some have been pruned to about 10 inches above the ground. I would rather cut down to ground level.