9 Drought-Tolerant Plant Combinations to Plant in September

September is perfect for planting. Perennials have time to establish in moderate conditions before winter extremes. Trees and shrubs benefit from cool temperatures, seasonal moisture, and less stress as they develop strong roots. Cool-season annuals show color until heavy frost or last all winter in mild climates.

While these plants need water when they’re newly transplanted, young, and developing roots this fall, once established, the carefree, hardy stock doesn’t rely on regular irrigation. Waterwise plants are becoming increasingly necessary. In addition to their low water requirements, they’re also often low-maintenance and easygoing performers with little additional resources needed.

Russian Sage

	common name Russian Sage
	botanical name Salvia yangii
	sun requirements Full sun
	height 2-4’
	hardiness zones 5-9

Russian sage thrives in hot, dry conditions and shines with silvery stems and leaves. Purple-blue blooms pack stems in the summer, creating an airy look among the fine foliage. 

Russian sage blooms reliably from summer until frost. As an easy-care performer across climates, it received the Perennial Plant Association’s Perennial Plant of the Year. 

Disease-resistant varieties like ‘Denim in Lace’ and ‘Crazy Blue’ are good for humidity-prone growing areas. In order to minimize damp conditions, ensure plenty of air circulation and well-draining soils. 

Coneflower

	common name Coneflower
	botanical name Echinacea purpurea
	sun requirements Full sun
	height 2-5’
	hardiness zones 3-9

Echinacea is a go-to for prolific flowering in a durable form. It grows naturally in North American prairies in a variety of soils, as long as they’re well-draining, 

Coneflower flourishes in the summer heat with continual color in vibrant purples, pinks, reds, yellows, and oranges, depending on the cultivar. Ray flowers surround a pronounced center of disc florets.

Moreover, coneflower grows across climates and has three seasons of interest in flowering and seed production. The long-lasting flowers are a nectar source for beneficial insects, and dried seed heads bring extended winter interest while providing food for wildlife. Deadhead spent blooms to promote faster flowering or leave them to be in their carefree state.

Penstemon and Switchgrass

This combination includes flowering perennials, textural grasses, and upright shrubs. Cotinus, or smoketree, is the focal point, with deep purple foliage. In contrast, the bright green and lilac shades create cozy lushness in the perimeter.

Smoketree is a waterwise, loosely arranged, multi-stemmed shrub. Delicate and hairy stems along flower clusters turn dusky pink and persist all summer for a hazy plumage. The foliage of ‘Royal Purple,’ a compact variety, is deep plum and maroon. Moreover, the standout shrub holds its color throughout the growing season.

Penstemon

	common name Penstemon
	botanical name Penstemon spp.
	sun requirements Full sun to partial shade
	height 2-3’
	hardiness zones 4-9

Penstemon bears tubular blooms in shades of violet-blue to scarlet on tall stems with long leaves. Busy bees and hummingbirds can’t resist visiting each blossom. 

‘Onyx and Pearls’ is a striking dark-leaved cultivar in rich purple-black with lavender-white flowers. Stems reach three and a half feet tall with full foliage. ‘Blackbeard’ is shorter but has similar dark purple and green leaves. Blooms are a darker lilac followed by burgundy seed pods.

The long-lived heirlooms grow in varying soil conditions and drought. They tolerate heat and humidity and are cold-hardy. However, they do best in dry, light, well-drained soils and moderate temperatures. Seeds benefit from fall or winter sowing to allow for cold stratification (exposure to cold temperatures and moisture).

Switchgrass

	common name Switchgrass
	botanical name Panicum virgatum
	sun requirements Full sun to partial shade
	height 3-7’
	hardiness zones 5-9

Switchgrass is a native North American prairie grass that grows across varying soil types, moisture levels, and light conditions. The ornamental blades form an upright column with high vertical interest. Clouds of plumes in the summer develop seedheads that last through winter. 

‘Northwind’ is one of the most vertical varieties, with fine olive-green blades. Leaves turn yellow and tawny in the fall for lasting appeal. Unlike some fall-pruned perennials, it’s best to keep these plants intact (cutting back in late winter) for movement in the cool-season landscape, with the added visual of seed interest and a food source for birds.

Switchgrass is rugged, preferring lean soils to overly rich ones. It grows in wet and dry soils and tolerates occasional flooding.

Aster and Black-Eyed Susan

In autumnal tones, purple asters and golden black-eyed Susan brighten the arrangement in complementary colors. The vibrant duo stands out among muted hues and fading warm-season bloomers.

Both perennials have an extended bloom season, and they can last through frost. In the border or containers, this pairing is exceptional for fall color. Planting in September is great to ensure the plants are established for spring’s continued growth.

Aster

	common name Aster
	botanical name Aster spp.
	sun requirements Full sun
	height 1-8’
	hardiness zones 3-8

Asters, with species native to North America, have blue-purple ray flowers with contrasting yellow centers. Their late-season blooms bring an infusion of color and benefit bees and other pollinators with their nectar-rich flowers.

Aster azureus, or skyblue aster, is exceptionally drought-tolerant and well-suited to dry or shallow soils. A. laevis, or smooth blue aster, tolerates various site conditions. A. cordifolius, blue wood aster, naturalizes along woodland edges and does well in dry areas.

While they withstand dry spells, asters flower best in moist, organically rich soils with good drainage. Plenty of air circulation is essential for vigor.

Black-Eyed Susan

	common name Black-Eyed Susan
	botanical name Rudbeckia fulgida
	sun requirements Full sun to partial shade
	height 1.5-2’
	hardiness zones 3-9

Like asters, black-eyed Susan is a native wildflower with an easygoing nature. The golden ray flowers have chocolate centers and rise on slender stems above dark green basal leaves.

Black-eyed Susans are versatile, thriving in heat, humidity, and dry situations. They grow with little gardener intervention. Deadhead spent blooms to promote a quicker flush of repeat flowering.

Rudbeckia is a clump-forming perennial that reseeds in the landscape. In the fall, let blooms go to seed for birds and wildlife and to expand the colony.

Catmint and Coral Bells

This pairing brings the delicate gray-green foliage of catmint with a cloud of blooms to the broad, dissected, multitonal leaves of coral bells. In summer, both bear a spray of flowers for visual appeal that buzzes with pollinators. Morning sun is ideal for both plants, with six hours of sunlight daily. They make beautiful, low-growing border groupings.

Catmint

	common name Catmint
	botanical name Nepeta spp.
	sun requirements Full sun
	height 1-3’
	hardiness zones 3-8

Catmint produces a haze of purple bloom spikes above softly mounding foliage. The flowers are mostly lavender and violet, with pink, white, and yellow species adding pastel shades. The aromatic leaves contain essential oils that act as a natural pest deterrent.

‘Walker’s Low’ is a high-performing variety with prolific lavender blooms. It tolerates humidity, heat, and salty conditions better than other selections. For its performance and ornamental value, it received the Royal Horticultural Society’s Award of Garden Merit.

Catmint grows robustly and thrives with neglect. Deadhead spent flower spikes or shear plants if desired to encourage new blooms more quickly after their initial flowering cycle.

Coral Bells

	common name Coral Bells
	botanical name Heuchera spp.
	sun requirements Full sun to partial shade
	height 1-2’
	hardiness zones 3-9

Coral bells have dynamic foliage with cultivars in deep plum, coral, chartreuse, magenta, and silver. The species is native to North America and has attractive green leaves. In addition to the bold foliage, sweet bloom sprays in pinks, corals, and reds rise in summer. 

Once established, heuchera is relatively drought-tolerant. When the leaves begin to curl and wilt, plants need water. They do best with some shade protection during intense afternoon sun.

Heuchera needs rich, organic soils with good drainage. In addition to catmint, it pairs beautifully with daylilies and hostas. Once established, it is also tolerant of dry spells.

Joe Pye Weed, Globe Thistle, Blazing Star, and Prairie Coneflower

This combination is perfect for a layered look rich in varying forms, colors, and diversity. All are low-maintenance perennials that require few additional resources to flourish. Whether a small-scale planting with a selection of each or a wide swath of plant groupings, these four sturdy performers shine in ornamental and ecological value.  

Joe Pye Weed

	common name Joe Pye Weed
	botanical name Eutrochium purpureum
	sun requirements Full sun to partial shade
	height 5-7’
	hardiness zones 4-9

Joe Pye weed is a tall, North American native with large, domed purple-pink flower clusters. It adapts to fluctuating moisture levels and tolerates moderate drought and occasional flooding. Rain gardens and woodland edges are ideal situations.

Its summer and fall flowers attract beneficial insects. Coarse, long leaves are dark green with purple-hued leaf nodes. Seed pods extend the plants’ interest into winter.

Sweet Joe Pye weed (E. purpureum) is among the most drought- and shade-tolerant species. E. fistulosum ‘Bartered Bride’ is a white-flowering dwarf variety with good performance across hot and dry situations.

The easy-going natives grow in different soil conditions, including clay. They thrive in rich, well-drained conditions.

Globe Thistle

	common name Globe Thistle
	botanical name Echinops spp.
	sun requirements Full sun to partial shade
	height 2-4’
	hardiness zones 3-9

Globe thistle produces blue globes of tiny florets that draw bees, moths, and butterflies. The stiff blooms make excellent fresh and dried floral arrangements. 

Attractive silvery-green foliage gives an all-over icy effect that cools down the display. They bloom from mid-summer through autumn and make an excellent back-of-the-border planting.

Globe thistle prefers soils that aren’t overly fertile, though it adapts to most soil types. To encourage continued flowering and to prevent reseeding, deadhead spent blooms.

Blazing Star

	common name Blazing Star
	botanical name Liatris spp.
	sun requirements Full sun to partial shade
	height 1-5’
	hardiness zones 3-9

Blazing star has tall, slender flower spikes in purple, pink, and white. Densely-packed batons appear in the summer heat and last until early fall. They provide a strong vertical accent in beds and fresh-cut florals.

Stiff, upright stems reach up to five feet tall, depending on the variety. Liatris ‘Lavender Glowsticks’ has exceptionally long bloom spikes in electric lavender along slim stems. ‘Kobold’ is a garden classic that grows to a manageable 18 to 30 inches tall with bright purple-pink spikes.

Liatris are hardy perennials native to North America, from Canada to Florida, depending on the species. Once established, they’re cold-hardy and withstand drought.

Prairie Coneflower

	common name Prairie Coneflower
	botanical name Ratibida columnifera
	sun requirements Full sun
	height 2-3’
	hardiness zones 4-9

Prairie coneflower is a long-blooming, easy perennial with yellow, red, or dark maroon flowers. The unique ray petals flare behind a leading central disc on tall, slender stems.

Prairie coneflower grows vigorously and may need thinning in optimal conditions. Pollinators and songbirds enjoy the nectar, pollen, and seeds as a food source.

The North American native grows wildly in dry plains, meadows, prairies, and disturbed sites. Its interesting floral form, vibrant tones, and easy care make it optimal for challenging garden sites.

Lavender, Daylilies, and Yarrow

This complementary scheme features deep purple lavender against sunny yellow yarrow and gold and orange daylilies. Artemisia adds a pop of silver foliage. A study in contrasts, the layered textures and bloom sprays create a rich display with rugged durability. Each selection thrives in sunny, warm, and dry settings. If lavender isn’t winter hardy in your climate, opt for salvia, agastache, catmint, or Russian sage for a similar habit.

Lavender

	common name Lavender
	botanical name Lavandula spp.
	sun requirements Full sun
	height 3’
	hardiness zones 5-9

Lavender brings bold purple bloom spikes, silvery foliage, and an invigorating fragrance to the water-conscious arrangement. Whether it’s one of the many English, French, Spanish, or Dutch varieties, lavender creates a wave of color and natural aromatherapy.

This sun-loving Mediterranean plant grows in arid, warm summers and cool winters. Lavendula angustifolia ‘Munstead’ is a more cold-tolerant variety and an early bloomer with a compact habit.

Low-maintenance lavender prefers dry soils between waterings and often needs no supplemental irrigation. For improved performance in humid climates, look to ‘Phenomenal.’

Daylily

	common name Daylily
	botanical name Hemerocallis spp.
	sun requirements Full sun to partial shade
	height 1-4’
	hardiness zones 3-9

Daylilies are tough perennials that grow easily across hot and cold climates and have a long lifespan. They offer extended color with a succession of blooms on tall stems above clumping, bladed foliage.

Daylily varieties come in seemingly endless colors and flower forms, including ruffly, frilly, and double petals. Early, mid, and late-season bloomers ensure months of flowering among the selections.  

Daylilies benefit from deadheading to maintain a tidy appearance and direct energy to flowering, though they don’t require it. Avoid Hemerocallis fulva, an invasive species across much of North America.

Yarrow

	common name Yarrow
	botanical name Achillea millefolium
	sun requirements Full sun
	height 1-3’
	hardiness zones 3-9

Yarrow is one of the easiest perennials to grow and does well with a September planting. Its large, flat flower clusters in vivid colors attract bees, butterflies, and other beneficial insects. 

The North American native has fine, feathery foliage and broad, yellow flower heads on upright stems. Despite its commonality, there are many cultivars in red, melon, pink, white, and purple with varying heights and improved forms, ensuring dense and floriferous displays.

Achillea thrives in sunny spots with well-draining soil. However, it can also grow in almost any soil setting. Its effortless beauty transcends garden styles.

Hardy Geranium and Tall Garden Phlox

This drought-tolerant planting bed is full, floriferous, and brimming with combinations of perennials that withstand drying out between waterings in average summer conditions. The tall phlox is a blooming, leafy backdrop. Meanwhile, the geraniums grow low to the ground in the forefront. Daylilies and lavender add foliar and floral contrast.

Hardy Geranium

	common name Hardy Geranium
	botanical name Geranium spp.
	sun requirements Full sun to partial shade
	height 1-2’
	hardiness zones 3-9

Hardy geraniums, or cranesbills, are tough, billowy perennials with a soft, mounding aesthetic. Their attractive foliage is blue-green, and their flowers are periwinkle to violet to pale pink. 

Geranium ‘Rozanne’ is a top-performing hybrid with bright purple-blue flowers from spring and early summer and free flowering through fall. Known for its long bloom time and vigor, ‘Rozanne’ won the Perennial Plant Association’s Perennial Plant of the Year award as well as the Royal Horticultural Society’s Award of Garden Merit.

G. ‘Patricia’ bears magenta-pink cupped blooms with dark centers. This Royal Horticultural Society Award of Garden Merit recipient tolerates dry to medium soils and has a bloom season of spring through early summer. 

Also notable, ‘Brookside’ is another RHS award winner noted for its drought resistance among the group. The vigorous plants produce blue blossoms with white centers all season long.

Hardy geraniums grow best in organically rich soils and naturalize under optimal conditions. They aren’t aggressive or invasive.

Tall Garden Phlox

	common name Tall Garden Phlox
	botanical name Phlox paniculata
	sun requirements Full sun to partial shade
	height 2-4’
	hardiness zones 4-8

Phlox graces the summer display with domes of showy flowers on tall, leafy stems. The fragrant native perennial attracts butterflies and hummingbirds with its blooms from summer through frost. Cultivars boast deep pink, red, magenta, purple-blue, and bicolor blooms; some have variegated foliage.

Phlox is prone to powdery mildew in damp conditions. To prevent this, ensure plenty of air circulation and opt for disease-resistant varieties in humid climates.

Tall garden phlox needs organically rich, well-drained soils. Deadhead spent blooms to encourage reblooming. For even more drought-tolerant plant combinations, look to low-growing, ground cover phlox species. Despite their delicate appearance, some ground cover phlox varieties are highly resilient in rock gardens and dry situations. They form a mat of fine leaves and spring flowers.

Allium and Wild Rose

Another great drought-tolerant plant combination includes roses and ornamental alliums. Species roses like canina, carolina, rugosa, and virginiana are hardy, vigorous growers that adapt to varying conditions. The robust shrubs generally flower in late spring and early summer, perfect timing for pairing with alliums. If giant alliums (the massive globes of starry florets) don’t overwinter in your zone, opt for a more cold-tolerant, lower-growing variety, ‘Millenium,’ or pair roses with other early-flowering perennials.

The versatile planting pictured here also houses an Eastern redbud. The understory native trees tolerate dry spells and boast colorful heart-shaped foliage that follows a springtime floral show in lilac and fuchsia. 

Giant Allium

	common name Giant Allium
	botanical name Allium giganteum
	sun requirements Full sun
	height 1-6’
	hardiness zones 4-8

Giant alliums feature dramatic softball-sized flower clusters in spring and early summer. They bring high form blended with whimsy. The gorgeous globes in purple, pink, mauve, lavender, and white top tall, sturdy stems. Long and strappy blue-green leaves emerge in a bundle.

Fall is the best time to plant allium bulbs. Tuck them in as you plant daffodils and tulips and await the spring display.

Giant alliums are disease-resistant and carefree architectural plants. Once established, they’re drought tolerant and will live with a big display for years.

Virginia Rose

	common name Virginia Rose
	botanical name Rosa virginiana
	sun requirements Full sun to partial shade
	height 10’
	hardiness zones 3-8

Our example of a widely adaptable species rose is R. virginiana, native to North America. These shrubby, wild woodland roses have single deep pink flowers with bright yellow stamens. Flowers are large and showy and attract bees and other pollinators.

After flowering, the Virginia rose develops large, slightly flattened burgundy-red rosehips. They color early, providing outstanding seasonal interest and attracting birds and other wildlife. Leaves offer beautiful fall color; hips persist into winter after foliage drops.

Virginia rose is robust and has a long bloom season. It is adaptable to a variety of conditions and is salt tolerant. Virginia rose forms a natural hedge and is perfect for the native garden, border planting, and cottage garden. It also provides excellent shelter for wildlife.

Panicle Hydrangea and Grasses

It may be counterintuitive to think of a hydrangea as drought-tolerant, but it can be a great combination with native grass plants if grown in the right soil. The species Hydrangea paniculata tolerates hot and relatively dry conditions with aplomb (relying on regular seasonal moisture within their growing areas, that is). With more sun-tolerance than others, panicles are sturdy flowering shrubs.

With blooms that persist into fall, pairing hydrangeas with grasses adds unique seasonal interest. Consider evergreens like juniper, cedar, cypress, or yew for water-saving selections. Here, upright switchgrass provides vertical structure, while low-growing pennisetum brings tufted plumes.

Instead of pennisetums (fountain grasses) that may aggressively reseed, opt for native or non-spreading types. We’ll focus on ‘PeeGee’ hydrangeas and pink muhly grass for our combination.

‘PeeGee’ Hydrangea

	common name ‘PeeGee’ Hydrangea
	botanical name Hydrangea paniculata ‘Grandiflora’
	sun requirements Full sun to partial shade
	height 8-25’
	hardiness zones 3-8

Look to ‘PeeGee’ hydrangeas for tightly packed conical blooms that emerge in late summer to early fall. The pyramidal panicles begin as pinkish-red buds and open to lime-green florets and star-shaped flowers in creamy white. 

As the season progresses, the flowers transition to vintage pinks. Showy autumn foliage turns tones of yellow and purple-red before dropping. Moreover, these stately growers make excellent hedges, screens, or specimen plantings. They’re cold-hardy, and thrive in summer heat and humidity. Provide well-draining soils for plants to thrive.

Muhly Grass

	common name Muhly Grass
	botanical name Muhlenbergia capillaris
	sun requirements Full sun
	height 2-3’
	hardiness zones 5-9

Muhly is a fine-bladed native ornamental grass with airy pinky-red plumes. Wiry leaves in deep, glossy green rest quietly until the panicle explosion in the fall.

Plant pink muhly in a mass or to contrast flowering shrubs and perennials. For white plumes, ‘White Cloud’ lives up to its name. The variety blooms after pink muhly and has an open habit with dense white plumes.

Most importantly, muhly grass is low-maintenance, and tolerant of heat, humidity, and drought. It grows in poor soils, including clay, rocky, and sandy. It’s also highly salt-tolerant.