First of all, you should select the best time for splitting the ornamental grass. Usually, gardeners recommend spring time to perform this task as it is considered the best season for dividing ornamental grass. In spring, you can replant the divided grass and it will grow again within a short space of time.
You should carefully observe and decide which ornamental grass plants need to be divided. Only cut the ones that are long enough and are getting thin from the centre.
Make sure that the divided ornamental grass plants are at least 4 to 5 inches long. This is the best size for replanting the divided ornamental grass.
While dividing the grass, you should be very careful in making an angle of the spade. It should hit directly downwards to the clump of the plant. Then make another cut to the point from where you want to cut the ornamental grass.
You should also take care of the size and appearance of the ornamental grass while dividing or splitting it from the middle. You should maintain balance so it does not develop a rough look.
You then need to prepare a new place for replanting the separated portion of ornamental grass plants. You will not have much time after dividing the grass, as it will dry up and will be of no use if left for a long time in the sun.
Make sure you have also used at least four inches of mulch around the place where you want to transplant the divided grass. Also, watering the place will go a long way in helping the newly planted grass in growing roots.