Mildew-Resistant Phlox

Symptoms

• Powdery mildew is a fungal disease that appears on infected plants as a grayish-white powder coating the surface of leaves, stems and flower petals. The fungus extracts nutrients directly from the phlox causing the plant to decline and not grow as well as uninfected plants. A severe infestation causes the plant to weaken so much that it does not survive throughout the winter. Sometimes the phlox leaves will curl, twist and change color before the powdery stage appears.

Solution

• The best solution to the powdery mildew infestation is to grow mildew-resistant phlox varieties. Start with healthy plants placed in the proper location in full to partial sun. Do not overcrowd the plants so the leaves will dry quickly with good air circulation. Avoid sprinkling the phlox on humid days since this makes the humidity problem worse and encourages powdery mildew to form. Water the ground directly around the root area of the phlox plants. Control the disease by removing infected leaves and stems, when powdery mildew attacks the phlox.

Phlox Paniculata

• Some of the varieties of Phlox paniculata are resistant to powdery mildew. David phlox (Phlox paniculata "David") grows to 3 feet tall forming clumps 2 to 3 feet wide. White flowers develop in May and continue to bloom through June. Robert Poore phlox (Phlox paniculata "Robert Poore") reaches 4 feet tall with clumps 2 to 3 feet wide in U.S. Department of Agriculture zones 4 to 9. Bright purple flowers cover the plants in May to June. Other mildew-resistant phlox are Delta Snow and Speed Limit 45.

Phlox Carolina

• Carolina phlox (Phlox carolina) produces mildew-resistant varieties that grow 2 to 3 feet tall. This perennial develops pink flowers during the early summer. Five to 12 pairs of oval-shaped leaves travel up a hairy green stem. Carolina phlox grows wild in deciduous forests and at the margins of woodlands.