Despite its tendency to get powdery mildew, phlox is a very common perennial in the mid-Atlantic area. Many gardeners –as well as butterflies– love the old-fashioned, native plant for its tall stems of summer-blooming pink, purple, or white flowers. Phlox is actually a large genus comprising more than 60 species native to North America. There is wide variation — some plants are tall, low growing, or groundcovers, while some prefer full sun and others thrive in shady, woodland areas.
This year, before you purchase phlox for your garden, read about the recommended varieties in Mt. Cuba Center’s report. The horticulturists at the Trial Garden, Mt. Cuba Center, Delaware, completed a three-year study. They tested 94 selections of eight sun-loving species and 43 selections of two shade-loving species. For the sun lovers, they deliberately tested for resistance to powdery mildew, a fungal infestation of the foliage that creates an unsightly white powder. (This usually does not kill the plant but detracts from its beauty).
Of the sun-loving plants, within the species Phlox paniculata, top performers are ‘Jeana’, ‘Glamour Girl’, ‘Delta Snow’, ‘Lavelle’, ‘Robert Poore’, ‘Dick Weaver’, ‘David’, ‘Ditomdre’ (Coral Cream Drop), ‘Shortwood’, and the hybrid P. x arendsii ‘Babyface’.
“Jeana,” according to the report, “is, without a doubt, the best performing phlox from the trial. This cultivar was discovered growing along the Harpeth River near Nashville, Tennessee and named after its discover Jeana Prewitt.”
Interestingly, volunteers who monitored pollinator visitations in the trial garden, noticed that ‘Jeana’s’ pink flowers received 539 visits from butterflies over 2 years. Others phlox flowers received at best 117 and lower. ‘Lavelle’, second in place, received 117 visits indicating a marked preference for ‘Jeana’.
Horticulturists also trialed shade-loving woodland phlox (Phlox divaricata) and creeping phlox (Phlox stolonifera). Their report stated that the creeping phlox was easy to grow while the woodland was more difficult. However, they conceded that their initial plants of the woodland may not have been the healthiest. The best performers of woodland phlox are Phlox divaricata and P. divaricata ‘Blue Moon.’ With creeping phlox, best performers are Phlox stolonifera ‘Fran’s Purple’, ‘Home Fires’, ‘Pink Ridge’, and ‘Sherwood Purple’.
All photos courtesy of Mt. Cuba Center