Phlox grows against a fence in Tom Atwell’s garden. Tall garden phlox is a good choice for the back border. Photo by Tom Atwell
It’s been a good year for phlox. That won’t compensate for how awful the tomatoes have been, but we will take what we can get.
Reconsidering, maybe the phlox have been just their normal, reliably blooming selves, but they seemed brighter and prettier because of all of the gray, rainy days we’ve had.
Mostly I am thinking about tall garden phlox, or Phlox paniculata, which blooms from late June to September. Its flowers come in many colors, including red, white, pink, blue and purple. These phlox look good in garden beds, especially in the back of the border because they can get up to 5 feet tall. They also make excellent cut flowers.
We used to grow more phlox than we do now, but our garden is increasingly shady, and most garden phlox doesn’t do well in the shade.
Garden phlox is native to the Eastern United States, west to Iowa and south to Georgia, Alabama and Mississippi. A Native Plant Trust (formerly New England Wild Flower Society) map shows that it has been found in the wild in Maine in Cumberland, Oxford, Knox and Waldo counties, which is interesting but probably of no practical use to gardeners, who will likely plant cultivars, descendants of the natives that grow in the wild.
Phlox in Tom Atwell’s garden. It’s had a good year. Photo by Tom Atwell
Phlox prefer fertile, slightly alkaline soil, and should be planted 18 to 24 inches apart to ensure good air circulation. They don’t like dry soil, so water them regularly if they don’t get an inch of rain each week – not a problem this year. People who prefer shorter, bushier plants with more blossoms later in the season sometimes cut the stems back by about a third in mid-June or so. We’ve never done that.
In addition, it’s important to dig and divide the plants every three or four years. If you don’t, the centers of the plant may die out and air circulation will be reduced. I’ve mentioned air circulation a few times, with good reason. The biggest problem with phlox is powdery mildew, a fungal infection that turns the leaves white and weakens the plant. An article in “The Connecticut Gardener” recommends removing one-half to one-third of the stems in order to limit the disease.
Some phlox, such as the popular white cultivar ‘David,’ are resistant to powdery mildew. Another variety I plan to look for is ‘Shortwood,’ a cross between ‘David’ and ‘Eva Cullum.’ It is named for the garden of perennial plant expert Stephanie Cohen, whose lectures I always enjoyed at the former New England Grows trade show in Boston.
A shorter, earlier blooming phlox that I suggest for most Maine gardens is ground phlox, or creeping phlox. There are two types.
Phlox subulata, or moss phlox, likes full sun. In its native plant online catalog, Maine Audubon says the carpet-forming plant has reddish-purple, pink and occasionally white tubular flowers, which are fragrant. It blooms in April or May, grows 6 inches tall and can go on garden edges and rock gardens. Moss phlox attracts butterflies, moths, bees and hummingbirds.
Phlox stolonifera, also a Maine native, prefers the shade. O’Donal’s sells the 8-inch tall cultivar ‘Sherwood Purple,’ which it calls “one of the best ground covers for shade.”
Another native shade-tolerant low-grower is Phlox divaricata, or Wild Sweet William. The Missouri Botanical Garden website (a prime source for information about plants of all kinds) describes its blue flowers as showy and fragrant. I’d never heard of it until doing research for this column.
All of those early phloxes sound like fun, but for the next few weeks I’m just going to enjoy the continuing blooms of our tall garden phlox.
Tom Atwell is a freelance writer gardening in Cape Elizabeth. He can be contacted at: tomatwell@me.com.
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