Garden phlox bloom prolifically for six weeks or more in midsummer, producing richly colored clusters atop tall slender stems. These hardy perennials are ideal in garden beds or borders and produce sweet fragrance that fills the summer air. Reaching heights of 2 to 3 feet, these delightful flowers return for years with minimal care.
Garden phlox bloom in colors ranging from white and pink to rose, red and lavender. Many new cultivars boast bi-color blooms with a defined eye (either darker or lighter than petal color) in the center, providing a striking contrast of color.
Most garden phlox prefer a sunny location that receives six or more hours of direct sunlight a day, but tolerate partial shade. Those grown in full sun produce larger and brighter blooms. Some cultivars are bred for shade or partial shade.
Well-drained soil high in organic matter keeps phlox producing for years. The addition of compost or well-rotted manure in the spring boosts production and improves quality of blooms. These moisture-loving plants benefit from supplemental watering when soil dries.
Deadheading phlox improves blooming and reduces the risk of self-seeding. Many cultivars are hybrid with sterile seeds, but some will germinate. Phlox that self-seed do not remain true to color and gradually revert to the standard magenta. To maintain color, deadheading is advised.
Phlox rebloom with a second flush of blossoms if sheared back by several inches after the first flush of flowers fades. The second flush of blooms may be reduced in size and abundance, but still produces fragrant blooms rich in color.
Phlox are best propagated by root division. Lifting the clump of phlox every three years (or when blooms begin to decrease in size and abundance) and dividing the clump into several sections revives overgrown plants and creates new plantings. Add 2 to 3 inches of organic matter to the soil and mix in well. Replant a portion in the same location and plant others in similar lighting and soil. If left to naturalize, phlox spread to a wider area each year.
Phlox are susceptible to powdery mildew if grown without adequate air circulation or subjected to high humidity and wet foliage. Water in the morning to allow foliage to dry before evening. Thinning overgrown clumps to allow air to circulate often provides adequate protection. When buying new phlox plants, look for those resistant to powdery mildew