There’s a saying in Texas: “It’s hotter than a billy goat in a pepper patch.” I sense you understand the unbearable heat and humidity a Southern summer can produce. From Texas eastward to the Carolinas and down the Florida peninsula, the brutal summer not only wears down the human spirit, it diminishes many traditional “hot season” annuals. The fact is, come July, August and September, annual gardens are “strained” at best.
Even in August’s heat, the red and lavender tones of caladium leaves are wonderfully accentuated by red Egyptian starcluster and lavender angelonia.
Photo Credit: James Burghardt
Vivid blooms of ornamental purslane add spark to a combination of dark red coleus and variegated Cuban oregano.
Photo Credit: James Burghardt
Heat-loving butter daisy tends to reseed itself, popping up as seedlings the next season.
Photo Credit: Felder Rushing
Is that coleus? No! It’s the colorful ‘Magilla’ perilla.
Photo Credit: Dr. Gerald Klingaman
Cool down your annual bed with tones of white – like with the lovely variegated foliage of Alternanthera.
Photo Credit: Yoder Brothers
While other Americans may have no trouble with Petunia, Verbena, marigold and geranium in summer, gardeners in the Deep South find these beauties faltering by midseason. Daytime temps in the 90s, unbearably high dew points, steamy overnight temperatures and heavy downpours are tough on annuals. This causes staples like verbena, flossflower (Ageratum), petunia and some salvias to grow so quickly that they become leggy and often flowerless. Other annuals (like zinnia and geranium) simply succumb to rot or fungal problems and collapse. Trimming back selections can resurrect their vigor, but plants often sputter until fall. New sowings of cosmos, marigolds or zinnias flower and seed so fast you shouldn’t even blink.
By selecting plants that thrive in the tropical heat and humidity, gardeners along the Gulf Coast can better enjoy vibrant annual beds and containers during summer’s dog days. A number of sun-tolerant and shade-loving annuals (or tender perennials) are increasingly available for gardeners to span the months until more hospitable growing conditions return in fall. Some are regarded for their showy flowers, while others strictly for their foliage.
Flowering beauties. Among the annuals that solidly handle the extended tropical summer are Egyptian starcluster (Pentas), wax begonia and lantana. Find a landscaper unfamiliar with them and you’ve met a newbie. Look at any bed in front of a development sign or boulevard planting and you’ll see these plants’ dependability and redundancy.
The butter daisy (Melampodium) has bright green leaves and scores of quarter-sized, yellow daisies that reseed themselves. Angelonia, a snapdragon cousin, blooms in flushes across the summer in pink, purple and white tones. Excessive nighttime heat can delay the resumption of flowering, however. If drier conditions are an issue, try Madagascar periwinkle (Catharanthus roseus). It resembles impatiens in flower, but it’s a drought-tolerant sun-lover. Members of the Nirvana and Cora series are particularly resistant to fungus in high-humidity months.
Ornamental purslanes (Portulaca) are moss rose relatives but with larger leaves and stronger heat and humidity tolerances. Appreciating sandy, moist soils when hot, they flower low to the ground in cheerful colors. Those with shadier, moist gardens should investigate wishbone flower (Torenia). The clumpy plants are filled with white, blue, purple, violet or rose trumpets, and they mix beautifully with caladiums.
Foliage wonders. Coleus is an amazingly diverse plant group. With hundreds of cultivars, gardeners can find short, upright, mounding or sprawling selections in any variety of color, leaf shape and stem sturdiness. Plants with more red and purple pigments can handle lots of sun, while those with yellow and green colorations should get less. Coleus seems a cliché, but the sheer number of choices leads to success when designing, especially since they’re so easy to propagate.
Don’t overlook other amazing foliage annuals to supplement the bloomers in your tropical summer garden. Beefsteak (Perilla) is a large, robust plant that may be mistaken for a coleus. (‘Magilla’ is visually outstanding.)
Joseph’s coat (Alternanthera) is fast-growing, often with narrow chartreuse or purple leaves on stems that mound or become beautifully trailing. Bloodleaf/chicken gizzard (Iresine) has glossy leaves and colorful stems that can be yellow and green or blood red and pink. Finally, the stiff stems of variegated Cuban oregano (Plectranthus amboinicus ‘Variegatus’) can sprawl between other plants, introducing a refreshing white and green foliage accent. All these foliage plants can be pinched back and allowed to regrow freshly, as well as to produce young cuttings.
Combining the beauty and vigor of the heat-loving flowering annuals with the striking leaves of the foliage plants that thrive in hot weather is a sure remedy for the steamy summer annual bedding blahs. Interplanting these mid- and late-summer showpieces among traditional annuals on hiatus helps bridge that span before all plants shine again in fall. Also planting tender perennial classics like firecracker flower (Crossandra infundibuliformis), purple heart (Tradescantia pallida ‘Purpurea’), Caladium, elephant ear (Alocasia, Colocasia), yellow shrimp plant (Pachystachys lutea) and Canna brings added depth, excitement and tropical stamina to the hottest weeks of the summer.
Whether or not a billy goat gets hot eating the peppers in your garden this summer, do make sure he’s welcomed by a vibrant annual display that stands up to the most brutal heat and humidity around the clock. (And hopefully he’ll stick to just eating the peppers!)