Phlox – An American Perennial

 

Pink (Phlox amoena); white (a western alpine Phlox)
and blue (Phlox divaricata)

From spring to summer, native Phlox are one of the joys of my garden. Did you know they are uniquely American? Of almost 70 species, all but one are native to the continental US, that one species is native to Alaska, and 14 beautiful species are native to Georgia. They are hardy, adaptable, and quite colorful. All are considered to be perennial except for one.

Early naturalists in what is now America described the first species by approximately 1680. The genus was officially named Phlox by Carl Linnaeus using the Greek word for “flame” to describe how colorful they were. As plants were sent back to England, Phlox became an early garden favorite. A good reference book is Phlox:A Natural History and Gardener's Guide by James H. Locklear.

Many Phlox species have a light fragrance, and they are pollinator favorites. We have species that bloom early in the spring, others in mid-spring, and others in summer. There are species that are low and creep and others that stand tall. American phlox come in a range of colors: from deep pink, to white, to blue!

Phlox can be recognized (or differentiated from other plants) by two characteristics: their leaves are oppositely arranged and the number of petals in their flowers is five. In spring, some people mistake the non-native money plant (Lunaria annua) for phlox but it only has four petals. 

Phlox subulata at a home near me

Moss phlox (Phlox subulata) is an early bloomer that has long been a favorite in the South where it is sometimes called ‘thrift’ because of its color resemblance to the plant Armeria maritima which has that common name. Many an old home has remnants of earlier plantings, the bright pink flowers sometimes just peeking out of grasses in overgrown areas. Another early spring, creeping species is trailing phlox (Phlox nivalis). I believe this is the species planted among graves in old cemeteries. Both species do well in full sun and lean soil and generally have bright pink flowers (although nurseries have bred P. subulata into a wide range of colors).

Phlox nivalis at a cemetery near me

Two early bloomers for shade are woodland phlox (Phlox divaricata) and creeping phlox (Phlox stolonifera). Both are blue and a joy to see mixed along with other spring bloomers like spotted geranium (Geranium maculatum). Woodland phlox is the more commonly available thanks to nursery cultivation.

A wild Phlox divaricata in NW GA

Phlox stolonifera in my garden

Mid-spring to early-summer bloomers include quite a few species: hairy phlox (P. amoena), downy phlox (P. pilosa), thickleaf phlox (Phlox carolina), and smooth phlox (Phlox glaberrima). Phlox glaberrima was recently collected in a wide range of natural colors in northwest Georgia and propagated by Henning von Schmeling of the Chattahoochee Nature Center (such as the white one shown below). All of these are usually pink.

Hairy phlox (Phlox amoena)

Downy phlox (Phlox pilosa)

Thick-leaf phlox (Phlox carolina)

Phlox glaberrima 'Malcolm Hodges'

The latest species to bloom is aptly named summer phlox (Phlox paniculata). It is also the tallest as far as I know. It has been widely propagated over the years into a number of cultivars in a range of colors but it is most naturally pink. This one has had mildew issues and cultivated varieties have tried to address that. My favorite cultivar is one that was naturally found with numerous, smaller flowers called ‘Jeana.’

Pale color form of Phlox paniculata

Phlox paniculata 'Jeana'

Five Georgia species which I have not seen are large-leaf phlox (Phlox amplifolia) from north Georgia; the annual phlox (P. drummondii) which has reports from south Georgia; Florida phlox (Phlox floridana) from southwest Georgia; and speckled (Phlox maculata) and mountain phlox (Phlox latifolia or P. ovata), both from northwest Georgia.

If you’re interested in how Phlox might do for your garden, Mt. Cuba Center in Delaware evaluated numerous species and cultivars in their Phlox trial; there are summaries for sun and shade. Spring sales are a good time to pick some up.