Perennials can begin to get spindly and produce a smaller mass of flowers if the plants are not well-maintained in a flower bed. Phlox is a flowering perennial plant that should be divided to maintain a healthy flower garden. You can increase the volume of plants in your flower beds by dividing phlox plants. The division of phlox plants will invigorate and promote new growth. Tall phlox should be divided every two to four years in the spring before the flower buds form. The creeping phlox can be divided during late spring and summer every one to three years.
Dig around the perimeter of the phlox plant with the spade or garden fork and carefully lift it out of the ground.
Loosen the dirt around the roots of the plant. Remove any stones and dead stems from the clump.
Slice down through the clump using the spade or sharp knife and divide it into three to five new shoots with healthy root systems. Remove the dead or woody central stem of the original plant.
Plant the divisions into a prepared flower bed.