Ornamental grasses come in cool season varieties and warm season varieties, just like lawn grasses :-) Warm season varieties are best divided in spring as that is when their root development is strongest. Cool season grasses - like blue oat grass - are best divided in late summer/early fall as they begin their growth season. Root development is more or less dormant on these during the summer months.

Here is a list of cool season grasses:

�Achnatherum - Spear grass
�Alopecurus - Golden foxtail grass
�Arrhenatherum - Bulbous oat grass
�Calamagrostis - Feather reed grass
�Carex - technically not a grass, and many are evergreen
�Chasmanthium - Northern sea oats
�Deschampsia - Tufted hair grass
�Elymus - Wheat grass or Wild rye
�Festuca - Fescue
�Helictotrichon - Blue oat grass
�Juncus - technically not a grass, and may be evergreen
�Koeleria - Hair grass
�Luzula - technically not a grass, and will probably be evergreen
�Molinia - Moor grass
�Phalaris - Ribbon grass
�Poa - Blue meadow grass
�Sesleria - Moor grass
�Stipa - Feather grass (S. brachytricha, an exception, blooms in lt Aug or Sept)

Thank you. That's interesting. I noticed Calamagrostis is on your list. This is another one I've always divided in spring, but I've never had any problems doing so. I would hate to divide that one now, because it's just coming into it's full glory with the seed heads and all that. Blue Oat grass however would be kind of easy to do now, because mine rarely produce a seed head display. Some years they do, most years they don't. I grow 'em for the foliage.

Kevin

Calamagrostis is most definitely a cool season grass - one of the earliest to start growth in spring and also one of the earliest to bloom/set seedheads. In my area, this tends to be one of the grasses we cut back early, as it has pretty well done its thing by now and is looking rather straw-like :-)

Here is a link that might be useful: calamagrostis acutiflora

I should clarify something here. I grow Calamagrostis brachytricha which is very late to produce seed heads. In fact, they are only now beginning to show.

Kevin

how far are you dividing it??

just cutting half out of the ground.. and leaving the rest..

or making a multitude of micro divisions???

perhaps its your process.. as much as timing ...

not a grass guy.. so i am just offering a thought ... fwiw ...

ken

I dig the entire plant, evaluate how large it is and what the root system looks like and then cut into sections. I rarely cut a plant into more than 4 divisions unless it's really huge.

Kevin

For some reason I have never had luck in dividing or moving this grass. I have one plant that I know has been in the same spot well over 10 years. Do tell...what is the secret.