Mid-Summer – That Troublesome Period in the Garden

By mid-July, the heat of summer wears me down. I find myself wishing that the cold, carefree days of winter were near. Instead, the reality of at least six more weeks of searing sun, oppressive temperatures, and wind tires me. What must my plants be feeling! Most of the spring and early summer blooming plants are cool season plants that burst into bloom early and wane as the temperatures soar in our hot summer climate. It’s little wonder this inter-season from mid-July into September has left many gardeners, and gardens to repose, waiting for cooler times.

I was schooled on the convention that spring and early summer was the main season of flowering and that summer blooming annuals were needed for color for the rest of the year. I think that annuals became such must-have plants because gardeners didn’t know want to plant for later summer glory. Nature, having blessed the land with a plethora of spring beauties, a spectacular spring garden was the aim of most gardeners. Crocus bulbs imported from foreign lands started the spring show, augmented with hyacinths, daffodils and tulips. Late spring iris and early summer daylilies have finished their bloom; the season of dahlias and chrysanthemums is still many weeks ahead.

Why The United States Has the Advantage of Mid-Summer - Fall Gardens

The gardeners focus on spring and early summer plants can be credited to dependence on British gardening books and information dating back to the early Colonial gardeners. The full bounty of American native plants was still unknown to early settlers; they followed the gardening traditions of their home country. Yet every part of the United States, except for Alaska, lies south of the British Isles. British gardeners enjoy milder temperatures (thanks to the Gulf Stream) and longer day lengths than American gardeners in the summer months.

Latitude determines day length. But because the latitude of the British Isles is so much further north, their extra hours of summer sunlight do not make up enough for the heat experienced in the United States. July is the warmest month for both Amarillo and London. Amarillo’s average high is 92° (according to Timeanddate.com, the average high temperature varies slightly from one website to another) and London’s is 75°. Even though Britain has longer daylight in summer, we gain the daylight advantage in fall and winter. For example, around the fall equinox on September 25, in London and in Amarillo, there is approximately 12 hours of sunlight. London, being further north, looses daylight faster than Amarillo. London’s last 10 hour day of the year occurs on October 26th, and Amarillo’s last 10 hour day occurs more than a month later, on November 28th.

Previously, July and August are traditionally the troublesome months for flower displays. I remember the moment when I discovered the late summer-to-fall garden could be glorious. That moment was when reading The Garden in Autumn, by Allen Lacy. It was in the latter years of the 1990’s, a few years after completing my Texas Master Gardening training. Lacy’s book beautifully described numerous American native and non-native plants that bloom in the fall. He gardened in southern New Jersey, in a Zone 7 area. I wanted a garden that was a four-seasons garden, or at least one as close to it as I could (we do have some cold winter months). Since Amarillo, at that time, was borderline Zone 7, I thought I’d give it a try. I designated a front garden bed that would also be a fall garden using natives from the Americas mentioned in Lacy’s book, and from other sources. As things turn out, they bloomed earlier in the Texas Panhandle than in southern New Jersey. That is reasonable, as these plants require heat over a period weeks to “ripen” and flower. Being further south, they are ready 3-6 weeks earlier than in New England or north Atlantic coast states. (See note about trumpet creeper and heat below.)

The main thing I was surprised to learn, was how the United State’s temperate climate favors the late summer-to-fall season allowing us to enjoy a brilliant autumnal display of color, not just in foliage (although this is substantial), but in native colorful flowers too.

In my garden, the summer flower show begins during the dog days of summer, in mid-July, continuing through the month of September. Now, at the moment the searing and oppressive heat of summer seems endless, I take relief knowing my garden is about to explode into a riot of mid-summer color. Together, non-natives and this selection of plants native to the Americas finishes off the flower season on a high level. If you are a gardener that keeps tract of what blooms when, I am sure you will find the highest number of plants in flower during these hot summer-fall weeks. It doesn’t seem to matter if the summer is dry, or we are favored by summer rains, I’ve found these plants dependable no matter the weather.

Providing continuity, a good many native spring blooming perennials continue flowering right through summer into fall, when given monthly irrigation: calylophus, Missouri evening primrose, prairie zinnia, gaillardias, and prairie verbena, along with Blackfoot daisy, and chocolate flower to are several long blooming natives. Cold hardy Salvia greggii and S. microphylla varieties and hybrids begin to flower in the spring and carry on into November. It is in summer’s inter-season of mid-July through September when the hottest weather bakes the earth that many native plants reach flowering maturity.

Many of the stars of mid-summer are native to the eastern half of the United States and sub-tropical areas of the Americas, requiring additional irrigation. Others native to the southwestern United States and Mexico and are suitable for the dry garden. Plants from both these diverse regions can be paired together and still have the harmonious appearance of belonging together. Of the plants I've profiled, no color seems to dominate -- their range from white, yellows, pinks, reds, mauve to blue. Salvia, the sage genus, provides many plants whose bloom requires sufficient heat, becoming mainstays of the mid-summer garden. Some Salvia species are cold hardy and xeric, other Salvia species that originate in sub-tropical (Zone 8) or warmer areas are able to flower quickly and are used as annuals. Monardas, gaura, and trumpet creepers are among the first of mid-summer, cold hardy natives to begin their bloom. Closely following are the hummingbird mint agastaches, mistflowers, ironweed, and obedient plant. Boltonia and goldenrods are succeeded by asters, flame acanthus, California fuchsias, rock rose, gayfeather and a few native shrubs that begin their bloom in August and September. Mixed with native grasses, daisies, upright sedums, lantana, sunflowers, zinnias sown from seed; garlic chives, rain lilies, every corner of the garden blends into a vision of harmonic naturalness in color, texture, size and shape. By September, bed to border has been stuffed with a plant in bloom.

I've profiled many mid-summer to fall blooming plants below. Though this is not a complete list, I have focused on plants and varieties than are easily ordered or found in nurseries. Seek out these plants from native plant nurseries, like our own Canyon's Edge Plants in Canyon, Texas. Ordering from Prairie Nursery (http://www.prairienursery.com/),  Plants of the Southwest (https://plantsofthesouthwest.com/), and High Country Gardens  and several others brings them to your door. Bargains can be had at the big box retailers and home stores. Just this week I found two of the plants mentioned below, Turk's cap and Gregg's mist flower, on the sales shelf.

One note on nomenclature: we have gotten to know many of these plants in a genus, only to be told later they are reclassified into another genus. I’ve noted the name changes as I’ve found them. Most references still refer to their earlier botanic latin names. All the photos posted where taken through the years from Mid-July to September, or some perhaps the first week in October. I've tried to only include photos taken that accurately reflect this time frame.

Plants for Traditional Gardens

Medium water-use beds and borders have soil amended with organic amendments for better nutrients and drainage. Typically, these areas need to be watered every other week with an inch of water, if rain doesn’t occur and are mulched with organic mulch. I think of these as beds used for traditional gardens plants, rather than xeric, or drought tolerant plants. Adding sufficient organic amendments is an important component of these beds. (Read about the importance of amending soil here and here.)

Salvias

The backbone of mid-summer gardens are the sages. There are many sages, or salvias, to choose from for dry gardens, and more traditional garden beds. For more traditional garden beds requiring weekly to every other week irrigation, two salvias have been used for decades: mealy-cup sage, Salvia farinacea (a.k.a. ‘Victoria Blue’ salvia, or the blue bedder, photo at left), and the scarlet bedder (scarlet sage), Salvia splendens so named by Victorian era gardeners. These two perennials are used as annuals, due to lack of reliable cold hardiness, and their ability to flower well in their first year. S. farinacea is marginally cold hardy in the Texas Panhandle; S. splendens is cold hardy in USDA Zone 10-11.

Tropical, Texas or scarlet sage, Salvia coccinea, is another non-cold hardy perennial used as an annual. Discovered around 1777, Texas sage, S. coccinea, native to Mexico, naturalized in southeastern United States prior to European immigration, so it is considered native. Texas sage produces copious scarlet blooms summer to frost. One of the better known varieties is ‘Lady in Red’, which is more compact with brighter red flowers. However, size is a matter of location. In the Texas Panhandle, as it is not cold hardy, 18-24 inches is as tall as it will grow. I prefer ‘Forest Fire’ for it’s blackish bracts and added drought tolerance. ‘Coral Nymph’ is a peachy-pink to white cultivar. More varieties are available in white, pink, lavender and even orange – ‘Vermilion’. S. farinacea attracts butterflies. S. splendens and S. coccinea attracts both butterflies and hummingbirds.

Two more sages that are cold hardy to Zone 8-9 are Mexican bush sage, Salvia leucantha, and Salvia ‘Indigo Spires’. These are taller sages, growing to 3-4 feet. They begin to flower anytime from mid-July/August and continue until frost (can be as late as November). Mexican bush sage’s calyces are deep purple and whorled and the flowers are white with fine hairs covering both flower and calyx, giving the appearance of velvet. ‘Indigo Spires’ inflorescence is spike-like and loaded with rich violet flowers. For both of these salvias, dead-heading of spent inflorescences encourages repeat blooming and will give them a more upright appearance. The Amarillo Botanical Gardens has wintered over S. leucantha plants for three years now. (Two photos of S. leucantha at upper right.)

Also stretching the boundaries of cold hardiness is Salvia guaranitica 'Black & Blue', Brazilian Blue Sage, native to South America. For most salvias, their calyces are green, but the calyces of ‘Black and Blue’ is black and the tubular two-lipped flowers are blue. Exceptionally attractive to hummingbirds and people, alike. This plant is consistently shown to be cold hardy to USDA Zone 8, but will quite often over winter in Amarillo gardens. Black and blue sage performs well with weekly irrigation in well amended soil and part shade exposures. (Photo at left.)

To add spice to the fall garden display, another sage grown as an herb is pineapple sage, Salvia elegans, used in teas, fruit, and sweet dishes. It’s intense red, tubular flowers are highly attractive to hummingbirds, blooming in late summer into fall. The variety ‘Honey Melon’ blooms in early summer. Pineapple sage is a perennial shrub native to Mexico and Guatemala, but is not cold hardy in the Texas Panhandle. Rita Pelczar, writing for Mother Earth News, has overwintered this fragrant herb with heavy mulching in her Zone 7 garden and further recommends its leaves as a garnish to piña coladas and ice teas. (Photo at right.)

Agastaches. Another late summer into fall blooming garden staple are the Agastaches, known as hyssops and hummingbird mints. The aromatic Agastache genus is composed of about 22 species, all but one, A. rugosa (Korean mint) are North American native plants. The genus is divided into two groups. The hyssops group is composed of agastaches that are native from the Great Plains to the east coast and the Pacific Northwest. (The term hyssop should not be confused with the southern European native plant called hyssop, Hyssopus officinalis.) Hyssop agastaches bloom in the summer and attracts bees and butterflies.

The second group are called hummingbird mints, and are native to the Southwest and into Mexico. New Mexico is the hot bed of hummingbird mints. High Country Gardens, the mail order company for South West gardens, has made its reputation partly on the hummingbird mints. Hummingbird mints bloom mid-July into fall. There are many fragrant species, varieties and cultivars available, and, as its common name suggests, they attract hummingbirds. Two of my favorite species are A. cana and A. rupestris. Although the hummingbird mints grow in sunny dry conditions, they can take medium irrigation and afternoon shade. Good drainage is a must. Plant hummingbird mints in a location where their roots will be dry during the winter, as many will die from winter root rot. Do not cut the plant down until spring. Hummingbird mints can be mulched with organic or inorganic mulches. (Agastache photo at left, and at right with 'Bells of Fire' Esperanza, Tecoma stans.)

Asters. Over two decades ago, it was announced there were no native asters in North America. How could this be? We had been told for centuries that nearly ALL asters were North American. With the advent of molecular testing, the scientific and gardening world was informed that all American asters (OK, there is one, Aster alpinus) really belong to twelve other genera. The two genera where most of the “asters” have landed are Symphyotrichum and Eurybia. We can no longer use the botanical genus name Aster for these beloved North American plants. The type species (first named species of the genus) of aster is a European aster, and as our “asters” are not related to it. Our “asters” have to find other genera. Now, when we refer to our “asters” as asters, it becomes a common name, rather than a botanically accurate name. Having cleared that up, I’ll continue to use the term aster, as a common name.

Asters are great nectar sources for bees and butterflies and many of them bloom in mid-summer to fall. Asters are categorized as New England, New York, heath, calico, aromatic, smooth and wood asters. Most of the asters sold by the truckloads in the fall are New England and New York asters. They have brief blooming seasons and I have found some of them to spread by rhizomes. Although I love the look of New England and New York asters and value them as nectar plants, their two to three week bloom period is too brief for me.

One of the better asters to try is the aromatic aster, Symphyotrichum oblongifolium. (Photo at left with goldenrod and Calylophus.) Aromatic aster is native to many varied ecosystems east of the Rocky Mountains to the east coast and was discovered on the Lewis and Clark Expedition in 1804. The flowers have light purple rays and blooms in August into fall. It grows to about 2 feet and will spread modestly by stolons. Asters generally prefer regular moisture; aromatic asters can tolerate more dryness. Long and short tongued-bees and small to medium size butterflies feed on its nectar. There are several varieties on the market including ‘October Skies’ and ‘Raydon’s Favorite’. ‘Raydon’s Favorite’ is said to have a long bloom period.

The calico aster is also a favorite of mine, Symphyotrichum laterifolium, ‘Lady in Black’. I’ve grown ‘Lady in Black’ for a number of years as much for the foliage as for the masses of white/pink flowers that last for about 3 weeks. As ‘Lady in Black’ matures and spreads out during the summer, slowly the buds swell until the entire plant explodes into thousands of pinpoints of pinkish white flowers. This calico aster has more of a horizontal habit, so it needs a bit of room. The Chicago Botanical Gardens did a comparative study of aster and aster cultivars. For more information, click here. (Photo at upper right.)

Gaura. Another plant that begins blooming in summer and continues into fall is gaura, also known as whirling butterflies, Lindheimer’s beeblossom and false honeysuckle. It is native to Louisiana, Texas and into Mexico. Formerly named Gaura lindheimeri, it is now Oenothera lindheimeri (photo at left). We can still use the name gaura as a common name. It forms a short mounded basal rosette about 12 inches in diameter. The flowers rise 2-4 feet tall on thin, erect, wiry stalks. The flowers themselves have four petals that open white and turn to pale rose-pink as they mature. When in full bloom by mid-July, the plant gives an appearance of starry, white, airy mist from a distance. This is plant Claude Monet would have used in his garden in Giverny, if he had known about it. Gaura looks particularly attractive when combined with silver, purple and blue flowers and foliage. There are numerous cultivars of gaura, including compact forms. ‘Crimson Butterflies’ is a compact dark rose cultivar that tends to be a bit more drought tolerant. ‘Siskiyou Pink’ is a long-used light pink cultivar. Gaura prefers average garden soil and twice a month irrigation. It normally lasts 3-5 years in the garden, but is always worth replacing when it dies out. It can be divided in early spring, and it is said to reseed, but I have never seen it. It’s flowers are a nectar source for long-tongued bees and bumblebees. It is a host plant of the white-lined sphinx moth. (Gaura, University of Wisconsin-Extension)

Ironweed. Another native for late summer to fall is western ironweed, Vernonia baldwinii. Pink to purple blooms atop a study stem that turn rusty have given it its name ironweed. Space limitations have kept me from trying it, however it would be an excellent plant for any native plant garden. It is drought tolerant, but will greatly benefit from irrigation every other week. Height depends on the amount of moisture, but around 2-3 feet in our area. It is native to the Edwards Plateau of Texas north to Manitoba, Canada. Bees and butterflies feed on the flowers for nectar, and its a host plant of several moth caterpillars. Western ironweed can sucker; remove seed heads before they mature.

Obedient Plant. Another native plant similar in habit to ironweed is the obedient plant. There are a number of species, the most common is Physostegia virginiana. (Photo at right.) They are called obedient plants because each individual flower will, upon being pushed in any one direction, temporarily remain in the new position as if it were hinged. Obedient plant will grow 2-4 feet in height sporting tubular two-lipped light pink to pale lilac flowers on a terminal stalk, blooming bottom to top. Every other week irrigation (medium water-use) will keep obedient plant from running too much and standing upright without flopping over. Bumblebees are its chief pollinator. ‘Crystal Peak White’ is an award winning white cultivar. Makes a good cut flower.

Boltonia, or false chamomile, Boltonia asteroides, is definitely an under-used plantfor a medium water-use garden. It provides the quality of being able to see through the plant, similar to gaura, creating a dreamy, airy appearance. It is another flower Claude Monet would have painted in his garden. Home to moister areas from eastern and central North America, I found it to need only every other week irrigation in my garden. The plant grows to 5 feet and blooms beginning in late July through September with a myriad of tiny daisy-like flowers with white petals and yellow centers. I love it for the diffuse white element that blooms with obedient plant, pavonia, goldenrod, blue mist flower, and other native prairie plants. Boltonia spreads by rhizomes and seed, but is easy to control. A good cut flower too. Two main cultivars are available, ‘Snowbank’ and a longer blooming ‘Pink Beauty’.

Mistflowers. If you have a bit of garden space that needs filling up, blue mistflower or blue boneset, Conoclinium coelestinum, formerly Eupatorium coelestinum, might fit the bill. It’s highly adaptable to sun/shade, soil and moisture conditions, and spreads by rhizomes, however they are easily removed (so they say). Blue mist flower is native to central and southern states in moist areas, but has long been grown in Texas in our dryer and difficult soils. It is also called false ageratum, as the flowers, though taller up to a foot and a half, look like the flowers of ageratum. When viewed from a distance beginning in July, a patch or swath of blue mist flowers looks just like that – not an unpleasant sight during the heat of summer.

Solidagos. Another roadside weed made good is goldenrod (Solidago ssp.). Alot of people don’t like the sound of planting goldenrods in the garden, as goldenrods are accused of causing terrible allergy problems – actually caused by the pollen of ragweed. The pollen of goldenrod is too heavy to be airborne. Another strike against it is its aggressiveness. It can take over a bed within a number of years. This problem can be solved by careful selection.

Goldenrods are excellent nectar sources for bees and hummingbirds. There are many different goldenrods native throughout the United States, making them difficult to identify specifically. Native plant people sing their praises. “John Muir described it in almost religious terms: The fragrance, color, and form of the whole spiritual expression of Goldenrod are hopeful and strength-giving beyond any others I know. A single spike is sufficient to heal unbelief and melancholy.” (Mother Earth News.) Goldenrods have been used medicinally, for teas (Solidago odora) and dyes. It was one of America’s indispensable plants, before being called a weed. European growers and gardeners have really taken to the goldenrods, as ours are superior to European species.

It is recommended to choose only named cultivars or varieties that have been tamed. Two of my favorites are Solidago ‘Golden Baby’, (photo at left) which is a hybrid selection developed for the cut flower market in Europe, named 'Goldkind' over there. I’ve grown it for 10-15 years. ‘Golden Baby’ flowers in August with plume-like clusters of bright golden flowers at the end of upright stems. It does spread just a bit, which I like and find it easy to control and move to other areas of the garden. It grows to about 2-2 ½ feet tall and attracts bees and butterflies when in bloom. Golden Torch Goldenrod, Solidago sp. Wichita Mtns., is an unidentified species of goldenrod originally collected from the Wichita Mountains of southwestern Oklahoma. This species blooms in late August and September. Bright golden flowers light up the stem for most of the length and accumulate at the top to give the appears of a torch. Though slightly spreading, it is not a problem.These are only two of many goldenrods that would be excellent additions to your late summer garden. (Photo of S. 'Wichita Mtns. at right.)

One variety that is a problem is ‘Fireworks’ goldenrod, Solidago rugosa ‘Fireworks’, although it is highly praised in many publications. It is a terrible spreader and flops over before flowering. Digging out the rhizomes is a huge, long-term problem. I can see no reason to have this variety in the garden.

Monardas. Monardas are another must have plant for the summer and fall garden. There are four main species native to the United States: Monarda citriodora, lemon mint; M. fistulosa, wild bergamot; M. didyma, bee balm or Oswego tea; and M. clinopodia, basil bee balm. Blooming by mid summer, an established monarda can reach 1-5 feet tall, depending on species, soil and water. However, many of the monardas available are hybrid cultivars of M. x media and these are the ones we’re the most familiar with. They come in a wide range from reds, pink, lilac and purple cultivars. M. citriodora and M. fistulosa are more drought tolerant species. M. didyma and M. clinopodia and the cultivars require supplemental irrigation at least every other week. Monarda citriodora, also call lemon horsemint, is a native plant of the Texas Panhandle and makes an attractive addition to our native gardens. Teas from Monarda have long been made by Native Americans and early Colonists alike. A cup of hot water infused with leaves of any of these monardas (if not sprayed or grown with synthetic chemicals), pineapple sage, mint and lemon verbena makes a refreshing drink, hot or iced. Monardas increase by slowly spreading roots, though they are not invasive and can be easily controlled. Divide roots in spring for additional plants and to share with fellow gardeners. (Photo of Monarda citriodora at left). Monardas are terrific for pollinator gardens, attracting a host of bees, butterflies and hummingbirds.

Rudbeckias. Most of the Rudbeckias I've tried required more water than I was willing to give, except for Rudbeckia triloba, commonly called brown-eyed Susan. Brown-eyed Susan grows to 3 feet or so and puts out many small daisy-like flowers with yellow rays and dark brown disks. It is native to most states east of the Rockies. It is either a biennial or short lived perennial that reseeds. It has reseeded for me for 4 years, and I hope to see it every year. Its airy appearance pairs perfectly with goldenrod and boltonia. (Photo of R. triloba at right.)

Zauschnerias or Epilobiums. Another plant group that should be located in soil with good drainage and moderate irrigation are the Zauschnerias, now renamed Epilobiums. This is a large genera, but the species of interest is Epilobium canum, which includes the ssp. canum, garettii and laterifolium. These are California native plants whose common name is California fuchsias, hummingbird plants, hummingbird trumpet and fire chalice. The blooms look like those of red-orange fuchsias, they are hummingbird nectar plants. I’ve known them as Zauschnerias. Whatever they are called, they bloom from mid-July to September. High Country Gardens has a variety of cultivars. These are not xeric plants, and will do better with afternoon shade. And it’s best not to let snow pile on them in winter. I’ve tried many of them. For longevity, it’s best to follow their requirements, chiefly quite good drainage, afternoon shade and every other week watering. Having said that, I do have one plant that receives far less water but still thrives.

Zephyranthes. My favorite mid-summer bulb is the white rain lily, Zephyranthes candida, native to the Rio de la Plata region of Argentinia. Any time from mid-August after a rain, I expect to see small white crocus-like flowers opening on thin stems 6 inches tall. There leaves are a rich glossy green. Far better than autumn crocus they are compared to, white rain lilies continue to bloom after each rain even into October. It’s a delight of the late garden I look forward with much anticipation. Previously known as Cooperia candida. (Photo at right.)

Others. Other native plant groups that bloom well from mid-July into fall are the Heleniums, Rudbeckias and Eupatoriums. These are three superb genera of native plants grown throughout the South and moister Midwestern states. I have omitted them here as they seem to require more water than what I’m willing to give. Two garden or summer phlox favorites, Phlox paniculata and P. maculata, need rich, moist soil – “feet wet, clothing dry” to prevent mildew and fungus diseases. Look for mildew-free selections such as ‘Miss Lingard’ (white) and ‘Rosalinde’ (pink).

Plants for Dry Gardens

Dry gardens in the Texas Panhandle are gardens that have compacted clay soil amended for drainage, with minimal amendments for nutrients. Caliche soils need more amendments for nutrients than clay soil, but even with that, caliche soil is a disadvantage. Sandy dry gardens benefit from organic amendments that help retain water. Dry gardens with amended clay soil perform well with one inch a month irrigation, it sufficient rain isn’t received within a 30 day period. (Photo at left features Mexican blue sage, Anisacanthus and solidago in the background.)

Salvias. Summer time brings a slew of tubular two-lipped salvias into bloom to the dry garden. By July, Mexican blue sage, Salvia chamaedroides’s deep blue flowers begin, contrasting their blue-gray leaves nicely. Mexican sage is native to Mexico from 7,000 – 9,000 feet in elavation and is sometimes called germander sage. Drought and cold-hardy, it’s true blue flowers begin to appear in July, and continue into November and in some years, December. Mexican blue sage is a terrific, compact semi-evergreen woody perennial.

Low growing with purple flowers, desert purple sage, Salvia dorrii, and taller (to 30”) purple Mohave sage, Salvia pachyphylla (Photo at left), join in. Both these desert salvias have whitish-gray leaves, and Mohave sage’s leaves and flowers are sticky, emitting a pine scent with rubbed. They favor lean, well draining soil. Avoid watering in the winter, and avoid winter snow pile-up.

A xeric, but not necessarily desert, salvia is another Mexican sage, Salvia darcyi. First discovered in the Sierra Madre Occidental Mountains at around 9000 ft., it is cold hardy to Denver, and perhaps beyond. Blooms by mid summer and just keeps expanding, putting on a splendid show through fall. This Mexican sage can be placed in a bed with weekly watering. 'Pscarl' (Vermilion Bluffs® Mexican Sage) is the Plant Select introduction. Windwalker® Royal Red Salvia hybrid cross, Salvia darcyi x S. microphylla, is another possibility from Plant Select if you have the space, 4’ x 4’. It is treasured for it’s exceptional cold hardiness, down to -20º. It’s highly prolific burgundy calyces and stems contrast handsomely with the green foliage and rose-red flowers, and blooms earlier, beginning in June into fall.

Pavonia. Besides the sages, or salvias, many other plants provide mid-summer into fall flowers. With few summer flowering plants that will bloom in shade, pavonia or rock rose, Pavonia lasiopetala, fills this need, blooming in sun as well as shade. Its a member of the mallow family with one and a half inch pink flowers resembling tiny hibiscus flowers. Each flower puts out 5 seeds. For me, it begins blooming in late July and August in shade, and would most likely bloom earlier in full sun. Blooms continue until frost. Simply cutting the dead foliage down to ground level in late winter or early spring is the only maintenance required. Pavonia provides nectar for butterflies, moths and hummingbirds. Even though it’s native range is from the Edwards Plateau south into Mexico, I and others have found either the original plants or its seedlings to be consistently cold-hardy every year for at least 10 years.

Turk’s Cap. Another member of the mallow family, Turk’s cap, Malvaviscus arboreus var. drummondii, is a late bloomer in the Texas Panhandle. Turk’s cap is native to central Texas and east to the eastern and Gulf Coast. It ranges in size from 2 feet to 8 feet, depending on temperature and moisture, the Panhandle being, most likely, it’s northernmost point for cold-hardiness, Zone 7. Turk’s cap is adaptable to many soil types, having thick roots that grow deep, and will flower in sun or shade. Because of this, it is often planted in shady locations. Though typically found in nature along streams or rivers, Turk’s cap is drought tolerant with unusual looking flowers for a mallow. “In Wildflowers of the Texas Hill Country, Marshall Enquist describes the flower as consisting of one- to two-inch-long petals that “stand erect and are folded into one another,” making a tight irregular bloom. A long red staminate column juts out from the center of the flower. The bright-green leaves are two to four inches long and wide, shallowly lobed, and slightly fuzzy on the underside.” (NPSOT, A nice bloomer during a hot summer.) Hummingbirds, butterflies, moths and other insects benefit from its nectar. One can find Turk’s cap blooming as early as May in south Texas and other southern locations, it normally blooms late here and into November.

Gayfeather, Liatris punctata, is a native fall blooming plant for the home garden, also known as dotted blazing star. Very drought tolerant, it can be seen blooming locally at Wildcat Bluff Nature Center and in Palo Duro Canyon in September. I have one clump that blooms in July, and another plant in September. Purple disc flowers crowd together on a stout stem, interspersed with short narrow leaves. To keep gayfeather from flopping over, keep it dry and in lean soil. Heavy summer rains, however, can have the same effect as over watering. Liatris spicata is a similar species that will better tolerate more moisture and watering practices. Butterflies and bees love this plant. Gayfeather is an exceptional cut flower. (Photo at right.)

Tansy Aster. Two aster-like native flowers to regions of the SW is Bigelow’s tansy aster, Dieteria bigelovii, and the hoary aster, Dieteria canescens (both previously in the Machaeranthera genus). They are both quite similar in appearance and difficult to tell apart. The purple aster-like flowers grow to about 2-3 feet tall. It’s aster-like flowers have purple rays and yellow centers, blooming August to October throughout the Southwest. Both of these plants will grow on available moisture in well drained soil. Avoid over amending the soil with organic matter. (Photo at upper left.)

Anisacanthus. Another plant that begins to bloom in July is flame acanthus, Anisacanthus quadrifidus ssp.wrightii. (Photo at left with hummingbird.) This plant forms an attractive heat and sun loving, drought tolerant small shrub with small, green glossy leaves. Young stems are a rich mahogany. From July until frost, orange-red tubular flowers cover the plant. Flame acanthus should be included in every xeric and native plant garden, it is so attractive and care free. Again, limiting the irrigation will keep the stems from falling over. A great hummingbird plant. The only maintenance required is cutting back the stems to the ground in late winter or early spring. ‘Mexican Fire’ is a cultivar with greener leaves and redder flowers, and ‘Pumpkin Pie’ has light orange flowers are two varieties available. 'Pumpkin Pie' flowers sparsely compared with the red-orange ssp. wrightii. ('Pumpkin Pie' photo at right.)

Mistflowers. Gregg’s bluemist flower or Texas ageratum, Conoclinium greggii is another plant that was previously in the Eupatorium genus. Gregg’s blue mist flower is drought tolerant native of Texas, New Mexico, Arizona and Mexico. It is cold hardy to Zone 7A. It’s leaves are finely cut, similar to a perennial geranium and grows to about 24 inches and will spread by rhizomes to 24 inches. It’s blooms are similar to, but bloom later than, the blue mist flower, C. coelestinum.

Leucophyllum. A Texas native shrub for the dry garden, Big Bend baromenter bush, Leucophyllum minus, will suddenly light up with violet flowers after a good July-September rain. Native to Big Bend, it is the only Leucophyllum reliably cold hardy in the Texas Panhandle. It will grow to about 4 feet tall and wide with evergreen gray leaves. This shrub is hard to find, so snap if up when you see it. No maintenance required. Many other barometer bushes are sold locally that are not cold hardy called Cenizo or Texas Ranger as a common name. Species in the Leucophyllum genus are called barometer bushes as they are said to flower before it rains. I’ve only seen it flower after mid-summer rains, usually beginning in mid-July. (Photo at the left of L. minus and a close up of the flower with a bumblebee at right.)

Another silverleaf Leucophyllum is Leucophyllum laevigatum, Chihuahuan Sage, that is rated cold hardy to 10°, a Zone 7 plant. It grows a little taller, to 5 feet and it’s flowers are more pinkish-purple to lavender.

Rabbitbrush, chamisa. A good number of shrubs are called rabbitbrushes. Most of them are classified as either a species of Chrysothamnus or Ericameria. To the average observer, the two genera are close in appearance. One thing they do have in common, is they are all fall blooming shrubs or sub-shrubs. These shrubs are native to the western half of the U. S., from the Rocky Mountains to the West coast. When seen in fall bloom, their crowns become a golden glow. Rabbitbrushes range from the dwarf size of 12 – 24 inches, to the regular sized species of 3-5 feet or more. The narrow leaves are light gray green to light grayish blue. Ericameria nauseosus (previously Chrysothamnus nauseosus) is one of the most common of the rabbitbrush shrubs. They are quite drought tolerant, heat and sun loving plants that live in poor akaline soils. Despite it’s specific name “nauseosus”, they have a pleasant fragrance. (Photo of rabbitbrush flowers at left.)

Broom Snakeweed, Gutierrezia sarothrae, is a very adaptable sub-shrub that grows from northern Mexico up through and into the prairie provinces of Canada. It looks similar to a rabbitbrush, but can be easily distinguished from the chamisa when in bloom. Broom snakeweed has ray flowers while rabbitbrush does not. Broom snakeweed grows from 8-36 inches tall, but usually only to about 18 inches. When driving through the shortgrass prairies and southwestern regions in autumn, the low golden glow is due to broom snakeweed or a closely related species. It is considered one of the worst rangeland weeds due to its toxicity to domestic livestock, however it is an important part of the ecology and a nectar source for many pollinators. Broom snakeweed is also one of the plants collected by Lewis and Clark. (Photo at right.)

Sunflowers. The Helianthus, or sunflower, genus is primarily a North American genus (except for 3 species). Most of the sunflowers people think of are the annual sunflowers, Helianthus annus, of just about any size and color (photo at left). They are best planted by seed after the soil has warmed, in mid May.

Maximilian Sunflower, Helianthus maximiliani is a perennial sunflower to the tallgrass prairie areas of the Great Plains. It is adaptable to many soils and conditions, growing 2-10 feet, depending on conditions. The plant itself is usually a central, unbranched, stout stem from which leaves are directly attached to the lower stem, and flowers forming off short branches. Staking may be necessary. Copious two to three inch diameter sunflowers with yellow rays and darker yellow centers bloom from mid-summer into fall. It may reseed in the garden. The selection ‘Santa Fe’ is one with prolific flowers. It provides striking seasonal color, needing space and strong associate plants. Many bee species, butterflies and beetles are attracted to the flowers, and the seeds are a food source for birds and small mammals. (Photo at right showing Maximillian sunflower laying down and small flower branches reaching upwardward.)

Prairie sunflower, or lesser sunflower, H. petiolaris, is the sunflower many people see growing wild across much of the United States. It originated in the western half of the country, but has now naturalized over much of the nation. It is an annual that grows 2-5 feet and is many branched, flowering from July to October. It is adaptable to many soil environments, but needs full sun. It attracts many bees, butterflies, moths and its seeds are feed for birds and small mammals.

Another sunflower, used more in traditional gardens, but can be kept under control by limiting water, is Helianthus x multiflorus, of which there are a number of cultivars, such as ‘Flore Pleno’ and ‘Loddon Gold’. This hybrid has been around since 1591 and is considered a sterile hybrid between H. annus and H. decapetalus that occurred naturally in Europe after the introduction of sunflowers. ‘Flore Pleno’ grows to 2-3 feet tall, features dark green leaves and bright yellow double flowers, and will spread by rhizomes, but can be easily controlled. Begins flowering in mid-July.

Trumpet Creeper. One of the easiest vines to grow is the Trumpet creeper, Campsis radican. Just give the vine a little sunlight and something to grow on, and you have it for life (even if you don’t want it). Yet a plant that grows so effortlessly for us, is the object of desire for northern gardeners. I remember one year on a trip back to my home territory in Wisconsin, while visiting in my brother's backyard, I spied a spindly, anemic vine, trained to a post in the middle of the lawn. It was slightly familiar. After asking what it was, he replied it was a trumpet vine, but he had never been able to get it to flower. He did the research and planted it in full Wisconsin sun. Temperatures never burned warm enough for his trumpet creeper to grow higher than 2 ½ to 3 feet, and never hot enough to flower.

Trumpet creepers are native to southern United States, including Texas and has naturalized much further north. It can grow up to 25-40 feet, necessitating strong structures to hold them up. By mid-July, clusters of three inch red-orange trumpet shaped flowers open and hang from current year’s vine. There are several cultivars available in yellow, orange and red. To attempt to keep trumpet creeper in check, cut back the stems to hard wood in the fall and dispose of any seed pods. Cutting back the hard wood to the ground will not kill the vine. The hybrid C. ×tagliabuana ‘Chastity’ is an infertile cross.

Other. Other plants native to the Americas used in mid-july to September gardens includes the many forms of the annual zinnia. Lantanas are rarely cold hardy in the Texas Panhandle. Likewise 'Bells of Fire', an improved cultivar of Tecoma stans (photo above near the top of the article on the right, with Agastaches), known as Esperanza are useful in the seasonal garden or containers, as they too, do not overwinter. These are definietly garden-worthy. All take some heat to expand and flower prolifically, usually by mid summer. 

In Summary

Over the last few years as spring warms earlier, cool season spring blooming wildflowers bloom earlier. Also noticed, as these early months warm sooner than average, warm season plants may emerge sooner, but they often do not bloom until air and soil temperatures have met the plants heat requirements, taking several weeks of heat to produce buds and flowers. Depending on each year’s weather, they may begin blooming in mid-July, or may delay their bloom until sometime in August.

During the hottest, sunniest, and sometimes driest months of the year is the period when the heat loving plants begin to light up the garden with an explosion of color. I've not had problems of insects or diseases with these delightful native plants, they are easy for garden with, requiring little effort. With the boon in native plant culture, we are learning that not just the spring, but summer gardens can look spectacular. These warm season plants, many of them native, are ideal for the mid to late summer garden, with many blooming into fall. (Photo of Solidago 'Golden Baby', zinnias and Victoria blue salvia in the background in early morning fog at right.)

Resources

A Comparative Study of Cultivated Asters, by Richard G. Hawke, Chicago Botanic Gardens, 2013.

Aster Name Change, Guy Nesom, January, 2010.

Flowers by the Sea, Nursery specializing in hundreds of salvias.

Gaura, Susan Mahr, University of Wisconsin-Extension, Madison, Wisconsin.

“Herb to Know, Pineapple Sage”, Rita Pelczar, Mother Earth News, June/July, 1993.

Landscaping with Texas Native Plants, Sally Wasowski and Julie Ryan, Texas Monthly Press, 1985.

NPSOT, A nice bloomer during a hot summer. Turk’s Cap.

Perennial Gardens for Texas, Julie Ryan, University of Texas Press, 1998.

Pitkin, Doree N., Grow Monarda Varieties: Bee Balm, Bergamot, Oswego and Horsemint,” Mother Earth Living, June/July, 2001.

The Garden in Autumn, Allen Lacy, The Atlantic Monthly Press, 1990.

The New Book of Salvias, Sages for Every Garden, Betsy Clebsch, Timber Press, 2003.

Angie Hanna, October 17, 2017