Perennial Phlox

Phlox paniculata

perennial_summer_phlox_9-2-15.jpg

Photo of perennial or summer phlox flower cluster.
This tall, late-blooming phlox has big, showy clusters of flowers.
Other Common Name
Summer Phlox; Garden Phlox
Family

Polemoniaceae (phloxes)

Description

A tall, late-blooming perennial phlox with big, showy, fragrant clusters of flowers. Flowers in dense, pyramidal, terminal clusters in many shades of purple, red-purple, rose, and rarely white. Cultivated forms come in many different colors and color patterns. Flowers in the typical phlox shape, with a narrow tube that flares out with 5 petal lobes. Blooms July-October. Leaves opposite, sessile, oblong to lanceolate, prominently veined, spaced apart on stems.

There are many horticultural cultivars in a great variety of colors that are found at garden centers and in home landscaping. This phlox is an old-fashioned favorite, and some of the cultivated varieties can be found growing untended at old homesites.

Size

Height: 2–4 feet.

perennial_summer_phlox_side_9-2-15.jpg

Photo of perennial or summer phlox flower cluster, seen from side.
Perennial Phlox (Summer Phlox; Garden Phlox)
Many “natural” occurrences of perennial phlox might actually be remnant populations of garden plants.

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Photo of perennial phlox cultivated variety
Perennial Phlox (Cultivated Variety)
There are many cultivars (varieties bred for specific traits) of perennial phlox. This cultivar has dark purple centers and more compact flower heads than the natural form.
Habitat and conservation

Occurs in moist soils in borders of woods, streamsides, below bluffs, and along gravel bars. Because it has been a favorite garden plant for so many years, and many cultivars have been developed, many “natural” occurrences of this plant might actually be remnant populations of garden plants. Look around for old foundations, cisterns, and other cultivated perennials and trees to see if you’re at an old homesite.

image of Perennial Phlox Summer Phlox Garden Phlox distribution map
Distribution in Missouri

Cultivated statewide; occurs naturally generally south of Missouri River and in east-central counties.

Human connections

An old-fashioned garden favorite that your grandmother might have grown, perennial phlox bears big, colorful clusters of flowers starting in midsummer. Some cultivars have problems with powdery mildew on the leaves, but native strains are more hardy.

Ecosystem connections

A variety of butterflies, skippers, and moths, including hummingbird-like sphinx moths, visit the flowers. Herbivorous mammals chew the foliage. Several types of insects also eat the leaves or suck the sap.