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Late Summer Perennials for the Midsouth

Many people quit visiting nurseries in Memphis in late July and August. Because of this, there are a group of beautiful plants that are at their best when Memphis is at its worst, late summer. These are the plants that will be coming alive when your roses have bloomed out, your yarrow is melting, and your creeping phlox is more creepy than fluorescent. Though there are many more, I have chosen 8 late summer bloomers to review, plants selected by our staff at Urban Earth.

Eutrochium dubium ‘Baby Joe’

Eutrochium dubium ‘Baby Joe’ (Photo by Martha Garriott)

Eutrochium dubium is commonly referred to as “Joe Pye Weed,” named after an American Indian herbalist from the New England area. Though found in other parts of the world, it is native to the coastal areas of eastern and southern North America, typically found along rivers and in swamps. To do well, it needs well-fertilized, constantly moist soil, but, if well sited, it comes alive in late summer with large blooms varying in shades from pink to purple. It does best in full sun but can handle part shade. Consider picking a low spot in your perennial garden that gets at least 6 hours of sunlight and planting either 1 as a specimen or a drift of several of these for a real show during the hottest part of the summer.

Since “perennial garden” is a near synonym for “butterfly garden,” it is hard to talk about perennials without talking about the butterflies they are known for hosting. Accordingly, this particular plant is known for attracting American Lady, Little Glassywing, and Zabulon Skipper.

The United States patent office issued a patent for the cultivar, “Baby Joe,” in 2009. Thus, this particular cultivar of Joe Pye Weed is still relatively new to the plant market. Discovered in a controlled growing environment in a greenhouse in the Netherlands, this cultivar is distinguished from the species for its upright and compact habit, moderately vigorous growth habit, a longer flowering period, large grayed purple-colored flowers, and strong and upright flower stalks. Despite billing itself as a dwarf plant, it can still get 60 inches tall, though more commonly it is seen around 3-4 feet. This is a good solid cultivar of a native (termed ‘nativar’) that would make a fine addition to any Midsouth perennial or butterfly garden.

Chelone lyonii ‘Hot Lips’

How could you pass on the opportunity to have a plant in your garden commonly known as ‘Hot Lips Turtlehead’?! The name alone justifies the purchase!

An Appalachian native plant, the specific epithet of the botanical name for Turtlehead, lyonii, is in honor of the American botanist, John Lyons (1765-1814), an early explorer of southern Appalachia. The plant is found in low spots in wet woodlands and along streams in its native habitat. Thus, like Joe Pye Weed, it needs constantly moist soil to do well. And, like most late summer perennials, it does best in full sun but can survive in part shade. Its flowers are pink and are often described as snapdragon like.

This nativar, ‘Hot Lips’ is distinguished for having more richly colored flowers and leaves than the species and red stems.

Rudbeckia fulgida var. sullivantii ‘Goldsturm’

Rudbeckia fulgida var. sullivantii ‘Goldsturm’

Black-eyed Susans (the common name for Rudbeckia) are prolific bloomers.  They have been a staple in Mid-south landscapes for at least as long as I have been alive. A native plant, it probably should be the Tennessee state flower. Sometimes called a coneflower, this common name is used less because it makes the plant too easily confused with Echinacea, another native, also commonly called coneflower. Though it is versatile in the soils it can tolerate, it seems to do best in dry to medium moisture soils. Thus, I have it in a high spot in my perennial garden in full sun. Though I do water weekly in July and August, I have noticed that it will get powdery mildew and/or septoria leaf spot if over-watered. (A light annual application of soil sulfur in early spring and pine needles as mulch nearly eliminates any risk of these problems.)

The nativar, ‘Goldsturm’, was introduced in 1937 as a cultivar of the variety of Rudbeckia fulgida, sullivantii. Recognized as the 1999 Perennial Plant of the Year, the plant was an overnight sensation (tongue-in-cheek), completely displacing the variety, sullivantii, in the market place. Personally, I find it superior to other Rudbeckia because it is more compact, growing to only 2 feet tall, making it less prone to flopping over in late summer. It also seems to me to bloom longer and more prolifically than others.  It certainly has a longer lifespan in the Midsouth than the biennial, Rudbeckia hirta. Though it can be planted as a specimen, this is a plant that looks great planted in drifts of at least 3 or even planted en masse.

Veronica x ‘Sunny Border Blue’

Blooms on Sunny Border Blue Speedwell just beginning to pop in late July 2018 in Memphis at Urban Earth (Photo by Martha Garriott)

Imagine the year to be AD31 and there is a hot and sweaty man being abused and carrying a cross, on his way to be crucified. A woman, depending upon who is telling the story, taking pity upon him, lends the man a cloth to wipe his face. He does so and returns it and when he returns it there is a perfect image of his face upon the cloth. The person lending him the cloth has been variously identified by different names, Seraphia (according to Ann Catherine Emmerich and Mel Gibson), Nike a.k.a. the Greek goddess of victory (according to the Italian writer and mystic, Maria Valtorta in The Poem of the Man God), and Veronica.

Whether you view this story as true, entirely fictional, or generously apocryphal, the relevance of the story is that this woman not only gets referred to in a song by Tori Amos and has a bullfighting technique named after her, but she has also been gifted by Carl Linnaeus, the father of modern plant taxonomy, with the privilege of being the eponym for a genus of about 250 plants that includes Sunny Border Blue Spike Speedwell, the name bestowed upon the genus officially around the year 1572.

How does this help you understand the needs of Sunny Border Blue Spike Speedwell? It doesn’t at all but planting and caring for plants is rarely done in isolation. It is the stories about the plants that we get to tell our guests as we give them tours that makes gardening a rich activity.

So, Sunny Border Blue starts blooming in mid to late July in our nursery and blooms well into the fall. It needs to be sited in full sun or at least part sun with soil that is neither as dry as a color guard yucca could handle nor as wet as Joe Pye Weed prefers, medium soil. About 2 feet tall, it shoots up gorgeous blue spikes and pairs nicely with yellow blooming plants like Rudbeckia or Solidago sphacelata ‘Golden Fleece’. It also looks nice next to Becky Shasta Daisies, a plant with white blooms and yellow centers, comparable in height to Sunny Border Blue. Though introduced in 1946, it was not as fully appreciated as it should be until named the perennial of the year in 1993.

Salvia greggii ‘Radio Red’

Josiah Gregg likely had a genius level IQ, working at various times in his life as a school teacher, a bookkeeper, a merchant, a lawyer, a photographer, and a medical doctor, but he is primarily known for his explorations and his best seller, Commerce of the Prairies, a two volume, 28 chapter treatise, based upon his travels in the southwest United States and Mexico. Born a little over 300 miles northeast of

Salvia greggii ‘Radio Red’

Memphis in Overton County, Tennessee in 1806, he died of starvation, falling off of his horse after getting lost trying to find his way back to San Francisco in the wilderness. But, in the mid 1840s, a few years before his death, he collected many plants, among them a plant commonly and variously known as Autumn Sage, Texas Sage, or Red Chihuahuan Sage, but more properly called Salvia greggi, the specific epithet in honor of Josiah Gregg.

The cultivar/nativar, ‘Radio Red’, is likely the most recent plant considered in this article, a patent for it having been issued in only 2016. It was the product of a controlled breeding program during the summer of 2008 by Scott Treyes in Aroyo Grande, California. Treyes was looking for plants with a compact growth habit and big blooms. ‘Radio Red’ appears substantially smaller, at only 18 inches tall, than its larger cousin, ‘Furman’s Red’. Supposedly, the blooms of ‘Radio Red’ are a deeper true red than any other Salvia gregii, but they appear to be only slightly darker, if at all darker than ‘Furman’s Red’ to this author. However, it is likely to bloom longer and is a more appropriate choice for smaller gardens or for the visual foregrounds, en masse, where a red bloom is needed in late summer. Once established, it likes fairly dry soil. So, be careful of over-watering.

All Salvia greggii are top hummingbird attractors in dryer climates. If paired with Blue Boa Agastache, your Memphis garden is sure to be filled with Ruby Throated Hummingbirds in most years.

Vernonia lettermannii  ‘Iron Butterfly’

The community of Allenton, Missouri, near St. Louis, is in a sad state. St. Louis County designated it as a blighted area, because of its chronic problems. Eureka, the larger nearby town, annexed it in the mid 1980’s, to solve Allenton’s water problems. Because of Allenton’s close proximity to the interstate and Six Flags (the amusement park), real estate developers targeted it at the beginning of the 21st century as a place for a shopping mall and 1700 homes. Getting the local government to exercise its power of eminent domain, they razed the entire town, but went broke when the real estate recession hit, before they could begin the development. Today, the community is a ghost town of concrete foundations.

Vernonia lettermannii ‘Iron Butterfly’ just starting to bloom.

But, in the world of botany, likely unknown to most nearby residents, it has much greater significance. From 1864 to 1871, it was the home of the great German-American botanist, August Fendler, who had moved there after leaving Memphis. It was Fendler that introduced George Washington Letterman to the world of plants when Letterman took a job as a school teacher in Allenton, meeting with Letterman to tutor him in plant identification 2-3 times per week in the years 1870 and 1871. Fendler, seemingly a roamer by nature, abandoned Allenton, as have so many others, but not before leaving Letterman with a deep love of plants, setting the stage for him to become one of the greatest American botanists of the 19th century.

Letterman, eschewing multiple offers by Harvard to join its faculty, stayed in the area his entire life, living out of a cabin there, but walking long distances, searching for plants and finding quite a few used in the nursery trade today, among them Vernonia lettermanii, named after him. Letterman, an unrepentant recluse, died in his little cabin in Allenton, attended only by a single neighbor, somewhat obscure but not insignificant, with plant species in 4 different genera named for him.

Vernonia lettermanii, sometimes commonly referred to as Slimleaf Ironweed, is found growing in the cracks within and between rocks in Arkansas and Oklahoma, its native habitat. It prefers hot and dry conditions, blooming purple in late summer.  ‘Iron Butterfly’ is a selection from Alan Armitage’s trials at the University of Georgia.  A more compact and more prolific bloomer than its species, it gets about 3 feet tall and 2 feet wide, at most. Site it in a high spot, relative to the rest of your garden, perhaps near plants like Colorguard Yucca, Russian Sage, Goldenrod, and Autumn Joy Sedum.

Solidago sphacelata ‘Golden Fleece’

Solidago sphacelata ‘Golden Fleece’ just beginning to bloom in Memphis July 2018 (Photo by Martha Garriott)

The goldenrod plant, for years wrongly accused as being the source of hay fever, has not been used much in ornamental horticulture. This particular selection, commonly called Golden Fleece Autumn Goldenrod, but more properly called by the botanical name, Solidago sphacelata ‘Golden Fleece’, was discovered as a spontaneous seedling in a garden in Eden, North Carolina in 1985, more compact and better blooming than the species. It was tested and introduced to the market by the Mount Cuba Center, in Maryland. Like William Faulkner, American switchgrass, and Jazz, it was better appreciated in Europe before being properly honored in its native homeland, the United States, winning the International Syaden-Union’s Award for an outstanding new plant in Swizterland in 1994.

This plant prefers a sunny and dry spot. So, site it in a higher spot in the garden, near plants like Colorguard Yucca, Ironweed, and Autumn Joy Sedum. Expect a plethora of butterflies and jealous gardeners to visit!

Perovskia atriplicifolia ‘Blue Jean Baby’

For lovers of blue blooming perennials, Russian sage has always been attractive. But, urban gardeners have often eschewed it, knowing it can easily get 5 feet tall and wide and needing more restrained

Perovskia atriplicifolia ‘Blue Jean Baby’ just beginning to bloom in Memphis, July 2018

plants because of their smaller gardens. But, ‘Blue Jean Baby’ solves this problem by being a dwarf cultivar of the species, topping out at about 34 inches. Additionally, it starts blooming earlier in the season than other Russian sages.

Conclusion

Perennials gardens are like a symphony. There should be a different section for the beginning, middle, and end of the show. Memphis gardeners are very strong at designing our gardens for a good show in spring and early summer but we are often weaker in planting for late summer blooms. Work these plants into your garden to make the end of the show better.

The author, John Jennings, has been manager of Urban Earth Garden Center since June 1, 2016. Before that he was a self-employed landscaper for 8 years, having worked as both a real estate lawyer and a drug counselor in previous lives. John is a graduate of the McCallie School, the University of Richmond, and the University of Memphis Law School. All photographs for this article are by Martha Garriott. Martha is a horticulturalist at Urban Earth, a retired social worker, and a Tennessee Master Gardener.

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