To many gardeners, the name phlox conjures up images of a fragrant perennial in the sunny mid-summer border. There is another phlox, however, Phlox divericata, that creates a cloud of shimmering blue and violet in woodland shade.
Woodland phlox is a delightful spring-blooming native that forms a creeping mound about one foot tall. As the common name suggests, it is a woodland wildflower, growing in forests, fields, and alongside streams. It prefers light to full shade, moist soil and a summer mulch of shredded leaves or bark. The foliage forms a mat of loosely entwined stems with semi-evergreen oblong leaves. The stems are both hairy and sticky.
Although its foliage does not have a strong presence, Woodland phlox makes up for this with ethereal drifts of flowers, in hues ranging from sky blue to violet, to rose and soft white. The sweetly scented blooms are formed in loose clusters of tubular flowers, each up to 1.5" wide, with five flat, notched, petal-like lobes that appear at the stem tips.
Woodland phlox is a natural mingler, chatting its way across the woodland floor. It weaves in and out of neighboring flowers, complementing spring flowering bulbs and providing a carpet for taller perennials.
As the leafy shoots spread along the ground, they root at the nodes, creating nice colonies. It is a great plant for naturalizing since it also self-sows to create soft drifts that blend well with other woodlanders.
Woodland phlox is what landscape design guru Piet Oudolf would call a “filler plant”. Plants are either “structure” or “filler” plants depending on their form, shape and texture. Structure plants have outspoken personalities that dominate their neighbors, while filler plants, which lack a strong presence of their own, weave around the others and fill in gaps. Filler plants like Woodland phlox, with its creeping form and soft hue, are vital to the garden, creating a seamless flow in the overall design.
Desirable cultivars of Phlox divericata include ‘Clouds of Perfume’ with its pronounced fragrance and powder-blue flowers; ‘May Breeze’, a soft-white phlox introduced by Piet Oudolf, and ‘Blue Moon’, the favorite dark blue selection of Bill Cullina, curator of the Coastal Maine Botanical Garden.