Gardeners - little help?

I’ve got obscenely large mounds of liriope in my front garden as a border, and I was told to cut them back in early spring to allow for new growth. How far down do I cut them? They are ridiculously thick, as I don’t think they’ve been cut down or thinned out in several years. I’m planning on dividing and moving some of them to another area - what’s the best way to do that? Pre-trimming? Post? Skip the trimming if I’m moving them? I’m a relative novice to gardening, so please feel free to dumb down the instructions.

Also - irises. When can I move those safely? I have some in a weedy overgrown area of the yard and I want to put them where I can enjoy them.

You can’t kill liriope. I don’t care what you do to it, you can’t kill it. I have dug up mounds of it in the heat of summer and simply tossed them onto baked Georgia red clay with no watering and have had them root and thrive.

So cut it down as far as you like. Dig it up and move it where you want to, pre-or post- trimming. Show it utter disdaim. It will thrive.

Iris, on the other hand, are a little more demanding. I’ve found the best time to dig and divide them is the fall. But you can dig and divide them pretty much any time after they flower.

Here is a very nice step-by-step tutorial (with photos) about dividing iris.