Pampas grass is a beautiful ornamental that comes back every year a little thicker and healthier if taken care of properly. Its tall fronds sway in the breeze, drawing your eyes to its tall dramatic plumes. It is a great focal point to any garden if there is enough room, or you can use it as a summer hedge along property lines.
Give it a haircut. It can get a little weak in the base if the dead growth is allowed to sit and collect decaying matter. There are a few ways to get around this, one of which is torching it. However, not all communities will allow open fire, so consider other options. When winter has arrived and growing has slowed down or stopped, get out your weed whacker and cut it down to about 12 inches from the ground. Be careful; wear gloves and eye protection, as the edges of the grass are quite sharp and can cut you easily.
Break up the mass of roots. The new shoots tend to grow from the outside edge, leaving the dry inner core to collect debris. After you have given it a haircut but before spring growth starts, use a pitchfork to pull off a section from the outside ring. It may take a bit of work and some sharp shears or a saw to cut through the mass. Replant the new section far enough away from other plants to allow for its rapid growth.
Rake out any leaves or other branches that have blown into the stems after you have cut them back. Use a metal garden rake as a plastic one will probably just get stuck and a bamboo one might just break with the tough stems.
Do not fertilize it or water it. This dessert plant needs almost no care. Some people even have a hard time getting it out of their yard once it is established. Plant it to the back of your landscaping bed so that it does not shade your other plants.
In the event that you need to remove it totally from your garden, the easiest way is to spray it with an herbicide such as Roundup® while it is still growing. It will take a little time but it should work quite thoroughly.