Plan the perfect garden with our interactive tool →

How to Care for Phlox Plants

Phlox is a low-maintenance perennial flowering plant that grows quickly and is attractive to butterflies and hummingbirds. The small colorful flowers are star shaped and cover the plant in a blanket during blooming. The plants are available in several varieties including a spring blooming ground cover and summer blooming tall border plant. Phlox is a fragrant plant that makes a nice cut flower. Plant phlox in the spring season once there is no danger of frost.

Phlox Plant Care

Plant phlox plants in a sunny location that has at least six hours of direct sunlight each day and partial afternoon shade. Choose a location with air circulation and a well-drained soil to prevent mildew diseases.

Prepare the soil by tilling in compost and granular fertilizer several weeks before planting.

Dig a hole twice the width and the same depth of the potted phlox plant. Add compost to the hole and place the plant in so the top of the root ball is at the same level as the ground. Fill soil around the plant and gently pack in place. Set the plants 1 ½ to 2 feet apart. Water plants generously after planting.

Apply compost around the plants in spring followed by 2 inches of mulch for weed control and moisture retention. Replace mulch as needed.

Water phlox regularly so the soil remains moist at all times but not wet. Phlox needs additional water during hot summer days that have less than one inch of rainfall per week to prevent wilting or decreased flower production.

Fertilize the plants twice during the growing season through the application of compost or a garden-flower fertilizer. Water the plants thoroughly after applying fertilizer to promote absorption.

Trim phlox and surrounding plants by cutting overgrowth and weak stems to promote air circulation. Cut back stems when the flowers begin to fade to promote new growth.

Divide phlox plants in the fall after 3 years of growth. This will decrease the chance of root rot and promote growth.

Cut phlox stems to a height of 1 to 2 inches after the first killing frost in fall.


Water phlox plants in the morning so the sun can dry foliage that has become wet.


Water at root level instead of on the plant as phlox are susceptible to powdery mildew disease initiated from wet conditions.

Garden Guides