It's true that liriope can be divided at virtually anytime of the year, even summer, as long as it goes into decent soil and gets regular water until it establishes. However, dividing, if you have to cut/chop the plants apart, tends to ruin the shape of the plant for awhile. If you wait and do it in late winter or very early spring, you could avoid this problem. We typically cut back monkey grass in February, and that would be the ideal time to divide too. As the new growth emerges, it will make the nice neat round shape from the start. If time and opportunity is more important to you, do it now.

correct - now is probably the BEST time to move it. Anytime before it blooms or again in the early fall when it starts making more growth. You can move this grass at almost any time in the growing season if you give it enough care but, it is best not to divide once it flowers - if only because you will loose the blooms. A.

Here in CA, I divide in February. Dig up the clump, place on driveway. Take shovel. Making sure each piece has adequate roots, cut into as many or few pieces as you would like. Plant divisions immediately in pots or the ground. Enjoy. Ease of digging up and dividing is another reason to love this particular grass.

What sort of climate are you in? (Please don't talk zones - they don't mean a thing to me! Mention things like temperatures, frosts, sun etc.) If a warm climate, you can divide lemongrass at any time - how else are you going to get to harvest and use it? It's easier to cut it back before harvesting - just because those leaves can be sharp, and they get in the way of the spade! You can keep the leaves if you want to use them instead of (or as well as) the white bits further down. If you live in a cold climate, the plant can be divided 'once the danger of frost is over' which I presume means 'in spring'. In a very cold climate, your plant may die right down, in which case, you should dig up the entire plant in early autumn, pot up sections of it and bring them inside and keep at a minimum temperature of 7C. When doing this, just keep the soil barely moist throughout winter, and plant out again in spring. Digging up the plant is, of course, your opportunity to divide and harvest it. In my subtropical climate, lemongrass is just too big and unruly for my tiny garden, so I now keep it in a pot. When the pot gets to bulging stage, whatever time of year it is, that's when it gets divided - unless I want to harvest it beforehand. Like any grass, if you cut it, it'll grow back in no time before you cut it again, and it grows.... and the clump gets ever wider and tighter.