Why Divide Ornamental Grasses

• to make more plants
• to preserve the strain of a particular named variety or favourite plant
• to renew an overly mature clump where some portions have died
• to stimulate new growth after some winter damage (perhaps relocate)

When to Divide Grasses

• divide when actively growing
• cool season grasses - spring, not summer; again in early fall
• warm season grasses - spring until mid-summer (do not divide any time during the flowering stage)
• evergreen grasses and sedges - spring only

How to Divide Grasses

• the exposed roots must not dry out
  • try to do this on a rainy or cloudy day
  • or cover any exposed roots to protect them
• smaller grasses can sometimes be pulled apart
• bigger clumps can be dealt with by prying apart, using 2 potato forks jammed straight down into the center of the grass clump. They need to be back to back with each other. Then push them apart at the tops of the handles
• a sharp shovel can penetrate the centers of some grasses
• for large clumps of grasses such as Miscanthus:
  • cut the foliage to ground level
  • use a wide-blade axe to hack the clumps into wedges or smaller pieces
  • pry out
  • further divide to desired size with pruners
  • trim away any dead roots
  • replant and water thoroughly
• another technique for large Miscanthus, etc
  • dig a trench around the grass clump
  • pry out the entire root ball with a shovel or crowbar
  • cut into pieces using an old hand or hack saw
  • replant and water thoroughly

Tip from Misha Dubbeld:

Dividing grasses using a reciprocating saw (equipped with a large toothed pruning blade) is an easy way to make clean cuts and maximize divisions with a minimum of damage to the root system. It reduces the work by at least 50%. Just dig the grass out as a clump and make your cuts with the saw. This method even worked for the tough as nails Miscanthus Giganteus (floridulus). Reciprocating saws are inexpensive, light weight and quite safe to use.

L Westrand suggests:

A DeWalt D25980K Pavement Breaker Hammer

"My son did the muscle work! My garden benefited."

L Bertrand's son dividing her grass with a DeWalt D25980K Pavement Breaker Hammer Click images to enlarge

Tip From Brad Weldon:

I use a reciprocating saw to divide the more vigorous grasses. It makes a nice and surprisingly clean cut.

Tip from E.:

Miscanthus 'Giganteus' is a great plant and I wanted to pass on a tip for dividing. I had a large clump of this in my garden and when I was moving...I wanted to take a piece with me... Two hefty guys plus myself and three substantial pry bars later we had the monster out of the ground. (The hole remaining looked like a bomb crater!) After several attempts at dividing using ever increasingly effective tools (or so we thought!) we finally resorted to a gas powered concrete saw! This we would recommend to anyone to use when wrestling with this specimen......it divided it up very neatly into 8 generous portions all of which survive in different locations around the Georgian Bay region of Ontario (Zones 4B to 5B).

P.S. We have quite a nice display of grasses at the Niagara Parks Botanical Garden, the 'campus' of the Niagara Parks School of Horticulture.

Tip from Bill Holt, Willowmist.com:

Use a hatchet or axe head (which you mention), but place it precisely where you want the cut and then pound it through with a heavy hammer, hand maul or sledgehammer. Much safer than axe swings, and even Grandma can do it - just takes her a few more hits. (I'm Grandpa... I know about this!)

Pics from Joe N., Ann Arbor, Michigan

A picture is worth a thousand words. Joe N. used an old handsaw and kept his lawn neat and tidy by putting a small tarp underneath. That made the clump easy to pick up and move while keeping the roots shaded. Smart Joe!

Joe has divided a clump of Miscanthus Click on the pictures to enlarge

Tip from "Missouri Barb":

I helped a relative divide LARGE clumbs of Misicanthus on their farm using a fence maintence tool - a steel bar about 7 feet long and and inch in diameter, with a 2" wide chisel shaped end. The weight of the tool combined with its sharp narrow end allowed me to repeatedly drop it in one spot until I cut through the dense roots. By cutting wedge shapes, then digging around the root ball, we were able to remove sections from extremely dense clay soil with much less effort than one would expect. I believe the tool is used to tamp rocks around fence posts - sorry I don't know its name.

Donna sent us this link to a tool called a Digger / Tamper / Spud Bar, which seems to be what Barb was talking about above.

Here is a great discussion on GardenWeb Forum. Lots of great advice for dividing huge Miscanthus plants. (new link as of June 2015)