OK to divide Hakonechloa grass now? (japanese forest grass)

My clumps are huge and I want to divide to form a new border. Should I wait until spring?
It comes up late but is just flowering now. Very beautiful, by the way, pest free and likes sun, shade, drought, and wet. South of Boston.

firebirds. .the American Hort Society Plant Propagation book recommends to divide in the spring and almost all other references I've seen say to divide in spring, with the exception of one person that divides it in mid-summer. At any rate, consensus is spring. You wouldn't consider sharing a bit of it for postage when you do your dividing. . possibly? Email me if you would. Thanks, Janet

So this will absolutely not spread via grass seeds?

susied. . firebird was inquiring about dividing hers. . Same reference says that seeds (nonvariegated forms only) of Perennial Ornamental Grasses (including Hakonechloa Macra) can be sown at a minimum temperature of 59 degrees.

Thanks for the info