Power Plants
View a jaw-dropping garden and it’s likely you’re seeing the potential of perennials at work. Trees and shrubs form the bones, and annuals add bright notes to a garden, but it’s perennials—herbaceous, nonwoody plants that go dormant in fall, then return in spring—that provide the textures, forms, and calculated sequence of colorful bloom that every garden needs. Once planted, a perennial garden can endure for years, even decades. That’s why selecting them is such an important process, one that can be challenging given the myriad new species and cultivars made available every year.
To come up with a group of perennials that could be considered the backbone of any well-planned garden, we turned to horticulturists Ruth Rogers Clausen and Thomas Christopher, authors of more than a dozen books between them, including their new guide, Essential Perennials (Timber Press). They gave us a short list of plants that deliver successive bloom—early, mid, and late season—and grow well in most parts of the country with minimal care (See our US Plant Hardiness Zone Map to see what works best for your region). For new gardeners, these tried-and-true picks are a great place to start; experienced gardeners on the hunt for exceptional cultivars will find those, too. Read on to see their favorite colorful perennials.
Shown: Riotous with high-summer color, this perennial border is built to last. After the delphiniums fade, purple salvias and strappy-leafed variegated irises keep the show going till fall.
Early Riser: Hellebore
(Helleborus)
Among the first to flower, these blooms often provide color while there’s still snow on the ground. Four species are commonly available, along with dozens of hybrids derived from them. Plant in clusters in shaded or woodland areas. Prefers rich, well-drained soil; once established, tolerates drought. Part to full shade. Grows up to 2 feet high and wide. Zones 4-9.
Choice cultivar The ‘Royal Heritage’ strain (shown) is superhardy. 3½-inch pot, about $14; waysidegardens.com
Early Riser: False Indigo
(Baptisia)
This drought-tolerant native is a butterfly and bee magnet and thrives where other plants struggle. Blooms mid to late spring. Blue false indigo has bright-blue flowers; other species and hybrids bloom in shades of purple, yellow, or white. Plant with Siberian irises, peonies, and spring bulbs. Prefers rich soil but is adaptable. Full sun. Grows 2 to 4 feet high. Zones 3-9.
Choice cultivar ‘Midnight Prairie Blues’ (shown) holds up in extreme heat. 1-quart pot, about $13; avantgardensne.com
Early Riser: Siberian Iris
(Iris Sibirica)
Prized for its strong, upright flower stalks adorned with intricately patterned flowers in rich colors—from white to violet to near-black. Blooms from mid-May through June. Grow with foxgloves, hardy geraniums, and perennial salvias. Prefers moist conditions, but tolerates a range of soils. Sun or shade. Grows up to 4 feet tall and wide. Zones 3-9.
Choice cultivar ‘Snow Queen’ (shown) is a white repeat bloomer. 3½-inch pot, about $12; bluestoneperennials.com
Early Riser: Peony
(Paeonia)
Famously fragrant, these nearly foolproof stunners boast a life-span of 50 years or more. Peonies typically bloom in late spring or early summer. Very early-blooming cultivars, such as ‘Coral Charm,’ are best for warm-weather regions. Intersectional peonies (a cross between herbaceous and tree peonies) produce huge blooms on rounded bushes. Plant with irises, baptisias, or foxgloves. Prefers rich, well-drained soil; once established, thrives on benign neglect. Sun to part shade. Grows up to 3 feet tall and wide, depending on variety. Zones 3-8.
Choice cultivar ‘Bartzella’ (shown) is an especially vigorous intersectional cultivar. 1-gallon pot, about $90; songsparrow.com
Early Riser: Coral Bells
(Heuchera)
Premier foliage plants with maple-like leaves in shades ranging from chartreuse to apricot, purple to pewter. Many exciting new leaf colors, variegation patterns, and leaf shapes were introduced over the past five years, including some with showy summer-blooming flowers. Plant en masse or pair with hostas, phlox, or toad lilies. Prefers well-drained, neutral to sightly acidic soil; good drainage is a must in shade. Sun or part shade; foliage may fade in full sun. Grows up to 2 feet high and wide. Zones 4-9.
Choice cultivar ‘Forever Purple’ (shown) is renowned for its color-fast deep-purple foliage. 1-quart pot, about $19; waysidegardens.com
Heat Seeker: Coneflower
(Echinacea)
While the tough-as-nails purple coneflower is a classic worth growing, new hybrids thrill with lime, orange, and hot-pink blooms. These colorful perennials flower for months, are drought tolerant, and are resistant to deer and rabbits. Plant with catmint and phlox. Prefers humidity, heat, and well-drained soil but is equally cold tolerant. Full sun. Grows up to 3 feet high and wide. Zones 4-9.
Choice cultivar ‘Hot Papaya’ (shown) is a fade-resistant orange. 3-inch pot, about $14; bluestoneperennials.com
Heat Seeker: Cranesbill
(Hardy geranium)
Not the annual bedding plant but a long-lived true perennial with a mounding habit and butterfly-attracting flowers. Plant under roses or with phlox or coreopsis. Prefers rich, well-drained soil; once established, tolerates periods of drought. Sun or afternoon shade in warmer zones. Grows up to 3 feet high and wide. Zones 4-10.
Choice cultivar ‘Johnson’s Blue’ (shown) is the truest blue-flowering cultivar. 3-inch pot, about $8; diggingdog.com
Heat Seeker: Phlox
(Phlox)
New cultivars of fragrant, tall summer phlox (P. paniculata) are more resistant to the powdery mildew that plagued older varieties. Other species, such as creeping phlox, add color to sunny slopes or woodland gardens. Plant summer phlox with coneflowers, daylilies, and perennial salvias. Prefers cool, moist, fertile, well-drained soils; few thrive in high heat and humidity. Sun to part shade. Summer phlox grows up to 3 feet high and 2 feet wide. Zones 3-8.
Choice cultivar ‘Shortwood’ (shown) is notable for disease resistance. 4-inch pot, about $9; perennialpleasures.net
Heat Seeker: Delphinium
(Delphinium)
While the species is famously finicky, new strains of hybrids (D. x elatum) combine the assets of their English relatives with a more vigorous, self-sufficient constitution. Plant with bee balm and Shasta daisies. Prefers rich, well-drained soil; treat as annuals where it’s hot and humid. Full sun to part shade. Grows up to 6 feet tall and 2 feet wide. Zones 3-10.
Choice cultivar The ‘New Millennium’ strain, including ‘Morning Lights’ (shown), is notably disease resistant. 4-inch pot, about $13; bluestoneperennials.com
Heat Seeker: Tickseed
(Coreopsis)
Hybridizers have been working overtime in recent years to develop new colors of this prairie- and cottage-garden favorite. Cold hardy and heat and drought tolerant, most species are worth growing, especially in dry, poor soils, but it’s the hybrids that excite with larger flowers and glossy leaves. Grow with salvias, echinaceas, and baptisias; cutting back after the first flush of bloom encourages repeat flowering. Prefers average but well-drained soil. Full sun. Grows up to 3 feet high and wide. Zones 3-9.
Choice cultivar ‘Red Satin’ (shown) is a new heat-tolerant cultivar with wine-colored petals. 1-quart pot, about $11; parkseed.com
Heat Seeker: Daylily
(Hemerocallis)
As close to fail-safe as a flower can be, but not your mother’s ‘Stella de Oro’; there are 60,000 registered hybrids, with more added daily. Hybrid daylilies are divided into several classes based on size, form, color, and bloom season. Choose yours for their aesthetics, then consider your climate to weed out all but those adapted to your region. Evergreen daylilies thrive in hot-climate gardens; dormant daylilies work well in colder zones. Tolerates many types of soil. Full sun. Grows up to 3 feet high and wide. Zones 3-9.
Choice cultivar ‘Tetraploid’ cultivars—such as the all-white, reblooming ‘Lady Elizabeth’ (shown)—are exceptionally vigorous, with larger flowers. Bare-root, about $22; whiteflowerfarm.com
Heat Seeker: Elephant Ear
(Colocasia)
Unequalled for its bold foliage, a must-have for Southern gardeners or in other parts of the country as a container plant. Yes, there are flowers, but plant this for the huge leaves in shades of black, purple, and chartreuse. Frost-sensitive, but roots can be dug up and overwintered indoors north of Zone 8. Add to cannas and calla lilies. Prefers rich, moist soil but tolerates ordinary garden soil if well irrigated. Sun or part shade. Grows up to 6 feet high and wide. Zones 7-10.
Choice cultivar ‘Black Magic’ (shown) has 2-foot-long purple-black leaves. 3½-inch pot, about $17; plantdelights.com
Heat Seeker: False Spirea
(Astilbe)
Rugged, beautiful shade lovers that send up long and colorful spikes above divided foliage in summer, a time when color in the shade garden is hard to come by. And they’re pest-free and deer resistant. Bloom time varies by variety from mid-June to the end of August; Astilbe x arendsii hybrids are especially diverse. Group in a woodland border, mass them as a groundcover, or mix with hostas, hellebores, ferns, hardy begonias, and lungworts. Prefers rich, acidic, moist soil. Partial shade. Grows up to 4 feet high, 2 feet wide. Zones 3-8.
Choice cultivar ‘Rhythm & Blues’ (shown) has outstanding hot-pink flowers over dark green foliage. 2-quart pot, about $19; soonerplantfarm.com
Heat Seeker: Sage
(Salvia)
Queen of Western gardens, perennial salvia is invaluable everywhere for its long-stemmed blooms and tolerance of drought and heat. Of more than 750 species, the most commonly available are the hybrids (S. nemorosa) valued for their aromatic foliage and spikes of purple, white, pink, and, now, sky-blue flowers. Attractive to both butterflies and hummingbirds. Plant with shrub roses, daylilies, coreopsis, and grasses. Prefers average, well-drained soil. Full sun. Up to 3 feet high and wide. Zones 3-9 (depending on species).
Choice cultivar ‘Wendy’s Wish’ (shown) offers long-lasting bloom of cherry-red flowers on maroon stems. 4-inch pot, about $13; burpee.com
Heat Seeker: Hosta
(Hosta)
Shade-tolerant, low-maintenance hostas are the most popular perennials in the U.S.A., with leaves ranging in color from gold to green to blue, often variegated. Along with new leaf colors and forms, plant breeders are currently focusing on creating cultivars with more-attractive and -fragrant flowers. Gold-leafed types tolerate more sun; fragrant-flower types (H. plantaginea) do best in the South. Plant with shade-tolerant shrubs such as azaleas and viburnums, or perennials such as ferns and hellebores. Prefers rich, moisture-rententive but well-drained soil. Part to full shade. Grows up to 3 feet high and 2 feet wide, depending on species. Zones 3-8.
Choice cultivar ‘Ambrosia’ (shown) is a new hybrid with very fragrant purple flowers. 1-quart pot, about $33; naylorcreek.com
Heat Seeker: Lavender
(Lavandula)
A delight to the nose as well as the eye; just make sure to choose the right species for your climate. English lavender (L. angustifolia) is the most widely adapted, thriving in Zones 5-8; French lavender (L. dentata) is best for the Southwest (Zones 8-10). Most bloom early to midsummer, though French lavender flowers almost year-round. The hybrids (L. x intermedia) have demonstrated better tolerance to heat and humidity than most other lavenders. Prefers well-drained, alkaline soil; excellent drainage ups the ability to thrive in cooler summers and cold winters. Full sun. Grows up to 3 feet high and wide. Zones 4-10 (depending on species).
Choice cultivar ‘Phenomenal’ lavender (shown) is a new hybrid that tolerates extreme heat and humidity and is resistant to foliar diseases. 1-quart pot, about $13; waysidegardens.com
Late Bloomer: Sneezeweed
(Helenium)
Blooming in autumnal shades of orange, red, copper, or yellow, this tall perennial is a standout in fall. Blooms constantly for six to 10 weeks from late summer till frost. Plant with catmint and torch lilies. Prefers cool, moist soil. Full sun. Grows up to 5 feet high and 3 feet wide. Zones 3-9.
Choice cultivar Few hybrids rival old-school ‘Moerheim Beauty’ (shown). 3½-inch pot, about $8; diggingdog.com
Late Bloomer: Black-eyed Susan
(Rudbeckia)
With their daisy-like flowers, tolerance for drought, and months of bloom, these natives deserve their rep as must-haves for the fall garden. Plant with grasses, sedums, and Russian sage. Prefers fertile, well-drained soil but tolerates average soil. Full sun. Grows up to 7 feet tall and 2 feet wide. Zones 3-9.
Choice cultivar ‘Goldsturm’ (shown) is more compact, with larger flowers. 3-inch pot, about $9; whiteflowerfarm.com
Late Bloomer: Aster
(Symphiotrichum)
These late bloomers bring rich rose and lavender hues to the fall garden. Of the many species and cultivars available, it’s the taller-blooming New England aster that’s the showstopper. Prefers moist, rich soil but tolerates a variety of conditions. Full sun to part shade. Grows up to 6 feet tall and 3 feet wide. Zones 4-8.
Choice cultivar ‘Alma Potschke’ (shown) is reliably disease resistant. 1-gallon pot, about $15; monrovia.com
Late Bloomer: Sunflower
(Helianthus)
Smaller than their annual cousins, perennial sunflowers are robust, long-blooming plants ideal for the back of a bed or a border. Daisy-like flowers in showy shades of yellow, orange, red, cream, purple, and bronze bloom by the hundreds from midsummer into fall, attracting bees and butterflies. Plant with grasses and late-season perennials such as goldenrods, asters, and Joe Pye weed. Tolerates a wide range of garden soils, but requires regular watering. Full sun. Grows up to 10 feet tall and 4 feet wide, depending on variety. Zones 4-9.
Choice cultivar ‘Lemon Queen’ (shown) has large pale-yellow flowers on long stems and blooms for two months. 3-inch pot, about $8; diggingdog.com
Late Bloomer: Korean Mums
(Chrysanthemum x Koreana)
Korean chrysanthemums are later blooming and have a softer form than typical garden mums. The foliage of Korean mums forms an attractive mounding shape all season long, even before the plant covers itself in daisy-like autumn blooms. The plants also tend to be pest and disease resistant and long-lived. Such a reliably hardy, late-blooming perennial should be much better known. Grow with sedums such as ‘Autumn Joy,’ goldenrods, or Russian sage. Prefers rich, well-drained soil. Full sun or part shade. Grows up to 3 feet high and wide. Zones 4-9.
Choice cultivar Chrysanthemum x ‘Single Apricot Korean’ (shown) blooms with abandon in mid-fall. 1-quart pot, about $9; nichegardens.com