Water established plants deeply every four to six weeks. Young plants are not as drought tolerant and need watered as often as required to keep the soil around them moist at all times. Exactly how often young plants need water will vary based on weather conditions and soil type, so check soil moisture several times a week.
Fertilize pampas grass growing in Florida each year in March, June and August with a balanced 8-8-8 fertilizer. Measure the diameter of the pampas grass clump and apply 1 cup of granular fertilizer per foot of diameter of the clump of grass.
Cut all of the grass shoots back to a height of 12 to 18 inches in January or February using pruning shears. Remove any weak stems and spent flowers during this renewal pruning.
Divide your pampas grass clumps in the spring using a shovel if they begin to thin out and develop unattractive open centers. The smaller divided plants can then be replanted or given away if you find yourself with more plants than you need.