Southeast Regional Reports

High Summer Perennials

These selections look fresh even on the hottest and muggiest Southern days

‘Timeless Treasure’ heuchera
‘Timeless Treasure’ heuchera (Heuchera ‘Timeless Treasure’, Zones 4–9). Photo: Andy Pulte.

The South has a diverse climate that fluctuates from state to state. There are even large amounts of variability across individual states. For example, in the state of Tennessee where I live and garden, the mountainous regions of East Tennessee are very different from the flatlands of West Tennessee. This makes the term “high summer” mean something a little different based on your area of the region. In fact, some in the lower parts of our region have a growing season that extends a full month past what I traditionally experience.

Summer in the South is hot, sometimes dry, sometimes wet, and always full of gardening challenges. However, there is no reason your garden can’t shine this time of year with the addition of some tough plants. Take time this month to walk through your garden in the cooler parts of the day and see what space you have to fill. Perhaps one of these proven plants recommended by experts across the region can add more blooms and enjoyment to your high summer.

Mississippi: Catmint is a steady performer

‘Walker’s Low’ catmint
‘Walker’s Low’ catmint. Photo: Michelle Gervais.

Lelia Kelly says, “My favorite high summer perennial is ‘Walker’s Low’ catmint, (Nepeta × faassenii ‘Walker’s Low’, Zones 3–8). Catmint is a true standout in high summer. Two cultivars that are particular favorites are ‘Walker’s Low’ and ‘Six Hills Giant’. I love the cool grayish-blue tint of the small leaves coupled with the light blue flowers. This combination during our blazing hot summers always puts me in a good mood. Shear the old flowers off for continued bloom throughout the summer. This jewel of a plant has no serious disease or insect problems. Deer and other critters leave it alone. It prefers well-drained soil, as crown rot may develop in overly moist soils. Provide full sun in the upper South; lower South needs some afternoon shade for best growth.”

Lelia Kelly is a retired professor of horticulture at the Mississippi State University Extension Service and remains active in the gardening world as a speaker at garden events and a contributor to several gardening magazines.

Georgia: Heuchera just won’t stop blooming

‘Pretty Polly’ heuchera (Heuchera ‘Pretty Polly’, Zones 4–9). Photo: Michelle Gervais.

Sheri Dorn says, “My favorite high summer perennial is heuchera (Heuchera spp. and cvs., Zones 4–9), hands down. It doesn’t stop performing! From my hot (shaded) front porch to the back garden under the camellia (Camellia spp. and cvs., Zones 6–10), my heuchera continually reward me with color and texture through their foliage and occasional flowers—and when they self-seed, it’s pretty interesting to see what results! They persist in the garden year-round, and I can use them in pots or in the ground. Definite winners for this very busy gardener!”

Sheri Dorn is a verified plant geek, according to her teenaged twins, Heath and Heather (did you catch the plant references?). She is known professionally as a University of Georgia Extension Specialist covering consumer ornamental plants.

East Texas: Large coneflowers have a sunny disposition

Large coneflower
Large coneflower. Photo: Michelle Gervais.

Jared Barnes says, “My favorite high summer perennial is large coneflower (Rudbeckia maxima, Zones 4–9). I love its cheerful yellow rays and the green disks that mature to a dark black. Once it finishes flowering, the seed heads persist late into the season. Even when it’s not in flower, the large, glaucous-blue foliage is a green foil for other perennials in the garden.”

Jared Barnes is an assistant professor of horticulture at Stephen F. Austin State University.

Tennessee: ‘Jeana’ garden phlox is pollinator friendly

tiger swallowtail butterfly sips from a ‘Jeana’ garden phlox
This tiger swallowtail butterfly sips from a ‘Jeana’ garden phlox. Photo: Troy Marden.

Troy Marden says, “My favorite high summer perennial is ‘Jeana’ garden phlox (Phlox paniculata ‘Jeana’, Zones 4–8). Discovered in Williamson County, Tennessee, by avid plantswoman Jeana Prewitt, ‘Jeana’ garden phlox is one of the most disease-resistant selections of phlox on the market today. Impervious to powdery mildew and highly resistant to leaf spot, the individual flowers are about one-third smaller than typical garden phlox, but the trusses are enormous—sometimes approaching 12 inches tall and 8 to 10 inches wide! ‘Jeana’ is sweetly fragrant, flowers from late June until early September, and is a magnet to butterflies and pollinators.”

Troy Marden is a plantsman and garden designer who has lived and gardened in Nashville for 20 years.

Louisiana: Rose mallow is a stunning show-stopper

‘Mocha Moon’ rose mallow
‘Mocha Moon’ rose mallow (Hibiscus moscheutos ‘Mocha Moon’, Zones 5–9). Photo: Andy Pulte.

Dan Gill says, “My favorite high summer perennial is rose mallow (Hibiscus moscheutos, Zones 5–9). Rose mallow is among the most spectacular of the summer blooming perennials. Blooms are unusually large (8 to 12 inches) and may be red, purple, pink, or white—often with a red eye. The attractive foliage may be green, tinted reddish purple or a deep maroon, and plants may grow from 3 to 6 feet tall, depending on the cultivar. Plant in full sun in average garden beds, rain gardens, or shallow water.”

Andy Pulte is a faculty member in the Plant Sciences department at the University of Tennessee.


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