With its countless, fragrant flowers in bright colors, the garden phlox is one of the most decorative shrubs in the summer. This is how to plant and care for it properly.
Profile of garden phlox:
Scientific name: Phlox paniculata
Plant family: phlox family (Polemoniaceae)
Other names: fall phlox, autumn phlox, perennial phlox, summer phlox, panicled phlox
Planting time: spring or autumn
Flowering period: June to September
Location: sunny to partially shaded
Soil quality: sandy to loamy, nutrient rich, humus rich
These information are for temperate climate!
Use in: flowerbeds, bouquets, stand-alone, group planting, planters, rose companion, borders, cottage garden, flower garden, natural garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 4 (-32 °C / -25 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of garden phlox
Plant order, origin and occurrence of garden phlox
The garden phlox (Phlox paniculata), also known as fall phlox, belongs to the phlox family (Polemoniaceae). The parent species come from banks and from sparse forests in the eastern United States. Phlox has been cultivated as a garden plant since the 18th century. Cultivation from the American wild species Phlox paniculata and cultivation with the meadow phlox (Phlox maculata) resulted in countless varieties, many of which have found their way into our gardens.
Characteristics of garden phlox
Garden phlox forms dense bushes of tall, upright shoots. The sturdy stems reach a height of 60 to 120 centimeters (24 to 48 in).
The dark green leaves are lanceolate and 8 to 10 centimeters (3.2 to 4 in) long. The top is bald, the underside often finely hairy.
With its bright colors, the plant attracts attention from afar. The flowers of the garden phlox shine in white, pink, red or purple from June to September. Not infrequently they are also two-tone. The plate-shaped flowers consist of five similar petals, which are often more vivid or contrasting colored at the base and thus form a so-called eye. They are very close together in a cone-shaped inflorescence, so that they like to cover each other. They exude a pleasant scent, especially in warm afternoon and evening hours, and attract numerous moths for pollination. The fragrance nuances range from sweet aromas such as honey and violets to spicy herbal notes.
Garden phlox – cultivation and care
The ideal location for the garden phlox is a sunny, airy place.
Phlox paniculata thrives best in humus and nutrient-rich, fresh to moist soil.
Planting garden phlox
Choose the planting hole so that the garden phlox is not pressured by neighboring plants and the leaves can dry off easily. Mix some compost into the excavated earth and water the young plant well. In order for garden phlox to thrive, it is divided after five to eight years and planted in a new location. To prevent powdery mildew or stem nematode infestation, you should not plant a phlox in the original place of growth for the next six years.
Provide the garden phlox regularly with compost or mineral fertilizer to sprout in spring.
If you want to extend the flowering period into late summer, you can cut back the withered stems by a third. Cutting back after flowering prevents the plants from sowing themselves and, with a little luck, encourages them for a second bloom. If you cut phlox correctly, you will extend the flowering time.
Be careful in midsummer: The root system of the tall perennials extends flat under the surface of the earth and can be easily damaged in drought. If the drought persists, you should water garden phlox frequently and thoroughly. Older stems grow out of the ground easily. You can pile them up with soil or divide and replant them.
In late autumn you can divide and transplant the garden phlox. First, cut off the dead shoots about a hand’s breadth above the ground. Then carefully dig up the rhizome and use a sharp spade to divide it into smaller pieces. You should insert the individual pieces just as deeply as before.
The varieties of Phlox paniculata as well as the species can be propagated by division or cuttings in spring or summer. Propagation by root cuttings is most advantageous. From the mother plant, root pieces 5 to 10 centimeters (2 to 4 in) long are taken and buried horizontally in potting soil with a portion of sand. The advantage of this method: You avoid the transmission of small stem nematodes, a type of roundworm (Nematoda).
Diseases and pests
The main pests of garden phlox are powdery mildew, froghoppers and stem nematodes. The risk of fungal attack can be reduced by paying attention to an optimal location and watering the plants vigorously in heat waves. If powdery mildew has already attacked the garden phlox, you can treat the plant with environmentally friendly sulfur. The best way to remove the froghoppers is with a jet of water from the garden hose. The insect likes to sit hidden on the leaf and suckle on the plant. The small stem nematodes, a slender, almost transparent nematode, attaches itself to the shoots of the phlox. It is best to cut off and destroy infected shoots immediately.
Garden phlox is hardy down to -32 °C / -25 °F. There are no protection for winter necessary.
Use in the garden
The multi-colored varieties of garden phlox are among the most important splendor-perennials for sunny borders. Due to their bright colors and the rich, long-lasting bloom, they are wonderfully suitable as leading perennials. Different companions are available depending on the color of the flowers. The red and rose-blooming varieties harmonize wonderfully with Indian chrysanthemum, dog daisies and delphinium. Yellow-flowering perennials such as sneezeweed, rough oxeye and goldenrod also go well with purple-flowered varieties. You can loosen up the arrangement with ornamental grasses such as small reed (Calamagrostis), switchgrass (Panicum virgatum), Chinese pennisetum (Pennisetum alopecuroides) or maiden silvergras (Miscanthus). Garden phlox is also very suitable as a cut flower for the vase and adorns summery bouquets.
The tried and tested varieties of Phlox paniculata include ‘Pax’(white), ‘Orange’ (orange-red), ‘Eva Cullum ’(pink with red eye), ‘David’ (white), ‘Mt. Fuji’ (white), ‘Prospero’ (white with blush of pink), ‘Bright Eyes’ (pink with crimson eye), ‘Delta Snow’ (white with purple eye), ‘Eva Cullum’ (pink with red eye), ‘Franz Schubert’ (lilac pink), ‘Laura’ (purple with white eye, ‘Nicky’ (deep magenta), ‘Red Indian’ (rosy pink), ‘Starfire’ (brilliant scarlet), ‘Robert Poore’ (iridescent purple) and ‘Prospero’ (white with red-violet eye).
The large, purple flowers of the ‘Uspech’ variety have a white star in the middle. The variety is very popular because it is resistant to powdery mildew and has a pleasant smell. The variety ‘Düsterlohe’ is also very resistant and can be up to 140 centimeters (56 in) high in some locations. The flowers shine in a strong, dark purple.