At 3-5 feet in height, tall Phlox will provide color to the middle or back of the summer flower border. 'David' is the best performing white cultivar. Buy garden Phlox paniculata at a discount.
This phlox plant is as tall as I am.
This picture was taken in the historic district of Philladelphia, PA.
You can count on the paniculata hybrids to bloom for at least 6 weeks in white, pink, red, purple, and even some bi-colors.
Some cultivars will begin to flower in mid-summer, some in early fall. Many are sweetly fragrant.
Tall white Phlox and orange Dahlias make a pretty planting.
Plants may be set out at any time during the growing season. Just be aware that, if you plant late in the fall, frost heaving may become an issue.
Plant so that the crowns are a little more than an inch below the surface of the soil. Mulch with 3 inches of pine needles or shredded leaves.
Shade decreases bloom and increases disease, so site summer Phlox in full sun. Keep them away from tree roots as the trees will compete with the Phlox for available moisture.
Incorporate lots of organic matter into the soil before planting as it will help with moisture retention.
Feed lightly with a balanced fertilizer twice each season. Once, when growth begins in the spring. Again just prior to bloom.
Keep the plants well watered but avoid wetting the foliage. Phlox is mildew prone. Provide good air circulation and spray occasionally with a fungicide to combat this.
Remove all but 5 stems per plant once they are 6 inches tall. Pinch the growing tips back now as well. This will cause the plants to become stronger and produce larger flower clusters.
Deadhead the spent blooms before they drop seed unless you want a bunch of seedlings. Most seedlings will produce magenta blooms no matter the color of the parents.
Divide the plants every 3 or 4 years depending on how quickly they grow.