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Back to News In The News – December 21, 2017

In The News

Spotlight on Phlox

Mt. Cuba Center research highlights native butterfly magnets

A longtime favorite of gardeners and butterflies is getting the spotlight. Phlox, first brought into ornamental cultivation in the 1700s, is a large-flowered native perennial garden plant that has enjoyed centuries of popularity in Europe, but has not been extensively trialed in the United States, its country of origin – until now.

In a newly released report, Phlox for the mid-Atlantic Region, Mt. Cuba Center’s research horticulturist details the results of three years of observation and testing of over 94 selections of different species of phlox.

Read the full report here: https://mtcubacenter.org/trials/phlox-for-sun/

“Phlox has bold flowers. They’re in clusters as big as a softball, if not bigger,” said George Coombs, Mt. Cuba Center’s Research Manager. “They bloom at a time when not a lot of other plants are blooming, right in the heat of summer, and butterflies love them.” Phlox can be purple, pink, white, and everything in-between. It suffers from powdery mildew, a fungal infestation of the foliage which strikes when the plant is stressed – in high heat or drought, and usually while flowering – casting a white, powdery look on the foliage. The condition usually will not be fatal to the plant, but it is unsightly for a cultivated garden.

“We wanted to test the plants’ resistance to powdery mildew, especially cultivars from European breeding programs,” Coombs said. “There are different disease pressures in Europe, so cultivars advertised as disease-resistant may not live up to that description.”

The Trial Garden at Mt. Cuba Center evaluates native plants and their related cultivars for their horticultural and ecological value. The goal of this research is to provide gardeners and the horticultural industry with information about superior plants for the mid-Atlantic region.

Coombs found the top-performing cultivars almost all came from U.S. cultivation, or were selections found in the wild. The top performer, Phlox paniculata ‘Jeana’, was discovered growing on a riverside in Nashville, Tennessee. While the plant was brought into cultivation for its strong resistance to powdery mildew, observers discovered it is highly attractive to butterflies.

“’Jeana’ was far and away the most popular for butterflies, especially eastern tiger swallowtails,” Coombs said. “We did some studies to determine why that might be, and we found that its nectar is no different from other Phlox.”

Mt. Cuba Center’s researchers used a team of volunteers to perform citizen science—called the Pollinator Watch Team. The team of fifteen volunteers conducted weekly observations of each plant in the trial to count the numbers of pollinators. Over the two-year observation period, they reported 539 butterfly visits to Phlox paniculata ‘Jeana’ (pictured below).

Other top-performing Phlox cultivars in the trial include: Phlox paniculata ‘Glamour Girl’, P. paniculata ‘Delta Snow’, Phlox x arendsii ‘Babyface’, P. paniculata ‘Lavelle’, P. paniculata ‘Robert Poore’, P. paniculata ‘Dick Weaver’ and P. panicualta ‘David’.