A Greene County Garden in July: Woodland Phlox

By Margaret Donsbach Tomlinson

In our changing climate, Greene County gardeners need plants that grow well in both hot summers and erratic periods of bitter winter cold. Native ecosystems may need to move northward in order to survive, and gardeners can help this process along by planting adaptable native plants. Woodland phlox (Phlox divaricata) is a great fit. It makes a showy burst of color in spring, often stays green through the winter and will tolerate dry weather. Its pastel pink or purple flowers attract butterflies and other pollinators, helping our native insects as well.

As its common name suggests, woodland phlox grows especially well in dappled shade, but if given a good start, it can also do well in sunnier areas. Generally no more than six to ten inches high, a group of plants spaced a foot apart will fill in to make a lovely, easy-care groundcover. Woodland phlox can also look charming spilling over the edge of a low retaining wall.

Native to most of eastern North America, woodland phlox survives both Canadian winters and scorching Alabama summers. In the shade under deciduous trees, where many garden plants struggle, woodland phlox comes into its own. The loamy soil created by many seasons of decomposing leaves is ideal for holding just enough moisture for the plants’ needs, while the trees’ root systems keep the soil from becoming too wet.

Although woodland phlox can be started from seed, it needs a period of moist cold stratification to germinate. Planting the seeds outdoors in fall suits their natural cycle, but aggressive, non-native weeds may outcompete the tiny seedlings. Another option is placing the seeds in a container with slightly moist sand or another planting medium and leaving them in the refrigerator for two to three months (making sure they don’t dry out) and then planting out the seedlings when they emerge. Of course, the easiest way to bring woodland phlox into a garden is to buy young plants by mail or in a local nursery. They will need regular watering at first to help them develop deep root systems, but will tolerate periods of drought once established.

Excellent native companions for woodland phlox include shrubs like Virginia sweetspire (Itea virginica), whose leaves turn a bright red-orange in the fall; mountain laurel (Kalmia latifolia), which also thrives in shade and has pinkish-white spring flowers; and red osier dogwood (Cornus sericea), which is native throughout Canada and most of the U.S. and provides winter color with its striking red stems. For gardeners who are not native-plant purists, woodland phlox also pairs beautifully with rugosa roses, whose bloom period overlaps with the phlox.