Deadheading improves the appearance of plants, may encourage a second flush of bloom and prevents self-seeding. (Garden phlox freely reseeds itself. However, most cultivars do not come from seeds.

Does phlox multiply?

Perennials, like phlox, need dividing every few years for many reasons – to keep them in control, to rejuvenate them or just to create more plants for other garden spots. ... As a general rule, phlox plant division can be done every two to four years in spring or fall.

How does phlox propagate?

You can also propagate phlox by taking root cuttings in winter, before they start to send up their spring shoots. Use plants dug up from the garden or pot-grown plant. Place the pots of cuttings in a cold frame, where they'll root and grow into new young plants by midsummer. They will then flower the following year.