Phlox - as American as apple pie !
Our Native Phlox
All phlox species are native to the United States. They are mostly from the southeast or South Carolina. Mostly perennial plants - just one of them is an annual. Butterflies love them !!!!!
Phlox blooms like crazy! Some species are so completely covered with flowers while in bloom that it is impossible to see any leaves. Most also have a light sweet fragrance.
Individual flowers have five petals and are held in cluster above the foliage. Colors range from white to pink, rose, red, magenta, purple, and blue. Some cultivars have flowers with multiple colors, often with a contrasting eye zone, or a petal edge.
Spring blooming species generally have a short, intense bloom period of 2 to 3 weeks. Summer flowering phlox may bloom over several months if deadheaded regularly.
The enemies of Phlox
Powdery mildew is by far the worst and most common disease of phlox. It starts by covering lower leaves with a grayish-white, powdery fungal growth in spring or late summer. Then it makes it way upwards on the plant and will leave it unable to bloom or grow.
There are several new cultivars that are not as susceptible to mildew - these are the ones you need to use ! The low growing ones are the most resistant.
To reduce the chance of getting mildew you need to promote good air circulation. Give plants adequate space - never let them get crowded. Overhead irrigation from sprinklers or hand watering also invites mildew - so keep the foliage dry.
Spider mites are the most frequent insect pest, mostly occurring in hot, dry conditions.
Types
Because there are so many species of phlox and they all interbreed its easier to simply focus on a few characteristics as a means to group them.
Low growing shade lovers. These are small moss or creeping phlox that grows to 3" . It includes woodland phlox and creeping phlox.
Low growing phlox for sun. These include hairy phlox and moss phlox. They get 6 inches tall.
Tall upright phlox. Two groups - one that prefers sun, the other part shade. Both can get to 5 ' and include Carolina phlox, spotted phlox and garden phlox.
Hairy Phlox (Phlox amoena)
Low growing, reaching 12 to 16 inches tall and 12 to 18 inches wide. It blooms in April and prefers full sun, but will tolerate some shade (very little).
‘Cabot Blue’ is the most common type, with lavender blue flowers
Moss Phlox (Phlox subulata)
A native to dry, rocky areas in the southeastern mountains. It is a tough plant, and forms an excellent, low, dense groundcover especially well suited for growing on slopes. An excellent choice for a rooftop garden !
Growing only 3 to 6 inches tall and 12 to 15 inches wide this one blooms in early spring. Usually the flowers cover the plants so completely that no leaves can be seen.
Moss phlox prefers full sun, and well-drained soil. Shade will cause plants to thin out, and they will not tolerate excessive moisture. To keep plants dense and improve appearance, either shear or mow with mower set at high setting after bloom is finished.
Creeping moss phlox
Similar Species
Other low growing, sun loving phlox species include sand phlox (P. bifida), trailing phlox (P. nivalis) and downy phlox (P. pilosa). All are tough plants that thrive in sun and tolerate drought once established. Downy phlox is taller than the others, growing to 15 inches in height.
Woodland phlox (Phlox divaricata)
This shade loving species is also called wild sweet William or wild blue phlox. Woodland phlox grows 12 to 15 inches tall in bloom, with the leaves forming a spreading mat. It blooms in early spring, about the same time as daffodils.
Grows best in moist, fertile, woodsy soil, with plenty of organic matter in part to full shade. It rarely ever gets powdery mildew.
Lovely icy blue flowers
Creeping Phlox (Phlox stolonifera)
Similar to woodland phlox, this one is lower growing - it also has oval rather than narrow leaves. Fragrant flowers are held in loose clusters 6 to 12 inches above ground in early spring.
Creeping phlox prefers moist, cool, well-drained soil, high in organic matter. Does best in dappled shade or in morning sun and afternoon shade. It WILL NOT tolerate full sun or wet soil.
Dappled sun and no direct sun is best for this phlox!
Carolina Phlox (Phlox carolina)
It is closely related to garden phlox (P. paniculata) and spotted phlox (P. maculata). With a strong upright growth habit, it can reachi to 3 feet tall and 1 ½ to 2 feet wide.
Flowers vary in color from lavender to pink to white. All these colors can also occur in wild plants. The flowers are held in small clusters at the top of the stems, blooming from May to late June, earlier than garden phlox.
Pink it is !
Spotted phlox (Phlox maculata)
Also known as meadow phlox and sometimes called wild sweet William. Also with a strongly upright habit it grows 2 to 3 feet tall and only 1 to 2 feet wide. Flowers tend to cluster at the top - a lollipop phlox!
Pink to purple flowers are sweetly scented. Flowers of wild plants are usually reddish purple. Blooming occurs in early to mid summer. Cut back the plant by half its height after summer bloom is finished to encourage repeat fall blooming.
Can be prone to mildew
Garden phlox (Phlox paniculata)
This is by far the best known of the tall phloxes, very commonly grown in perennial borders. Unfortunately, many of its cultivars are the most prone to powdery mildew.
We at Plant Specialists have opted for using other species as this one is always a struggle to keep it looking pretty without constantly using fungicides.
The tallest of them all !
For the best phlox selection - Call Plant Specialists TODAY !
Our Design or Garden Care Team can help you find tough mildew resistant ones for your garden!
Don't delay – the sooner the better !
GREENING NEW YORK FOR OVER 52 YEARS !
Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBA
All photographs used with permission from @SHUTTERSTOCK