If you need to fill a spot in your garden with a plant that needs almost no care, gets to be a good size, looks good for most of the year and comes back every spring, then consider growing ornamental grasses. You can purchase new plants or simply transplant some from a friend's yard. They should transplant easily as long as you follow a few guidelines.
Dig down about 12 inches, all the way around the clump of grasses, as early in the growing season as possible. You can transplant the grasses during the summer as well, but it gets harder to handle them as the grass blades grow longer. You also want to give the roots enough time to adjust before the time of their growing season ends.
Try to get your shovel or fork down under the clump of grasses and start to lift the clump up. Work your way around the plant and then lift one side up and out of the hole so that it lays on its side. Shake off some of the extra dirt that is not connected to the roots.
Use a saw or serrated knife to cut through the clump. Separate sections that are at least six inches in width or have at least three strong stems. Be careful to wear gloves or the sharp edges of the grasses are likely to give you cuts. Cutting through the dirt ball is very dulling to a knife so it will take some effort and you might have to sharpen the blade when you are done.
Set your new cutting into a prepared hole that is about six to 12 feet away from any other plantings, depending on the growth capability of your plants. Tamp the soil in firmly around the stem and water well. You will have a healthy full grass in two or three months.