Fertilize the plants with a nitrogen-rich formula at least once a month. When the flowers start to droop and their color starts to fade, use fertilizer to add more nutrients to the plants.
Water the grass. It is best to soak pampas grass once a week to make sure the roots get enough water to last throughout the week.
Pull any weeds around the plant so that they don't overtake the root area of the pampas grass. Use a spade and till the earth around the plants to rid the soil of any unnecessary weeds, but make sure not to pull out the plants when tilling. Add mulch to the soil to get rid of the weeds and keep the moisture in the soil.
Divide and replant the pampas grass when you notice that it is starting to die out. Use scissor shears to cut out any dead blades and compost them. Take the shovel and dig out the remaining clump of pampas grass and replant in smaller sections. After the smaller clumps have been planted, fertilize and water.
Use the scissor shears to prune the pampas grass to about 4 or 6 inches in height. This should be done every spring in order to let more sunlight warm the soil and help the new blades grow.