By the time mid-summer rolls around, us gardeners are looking to enjoy the fruits of our labors. We put in those long hours in early spring to prep, shop, and plant, and now it’s time to kick back and enjoy the season. The veggie patch yield is increasing daily, containers of annuals are established and thriving, and the perennial garden is… well, yikes, it looks kind of tired and needs some help!
With hot, harsh sunlight and dry conditions, mid- to late summer can be tough on our gardens. Many plants suffer from heat stress and struggle without adequate moisture. To avoid the late season, colorless doldrums, choose from our list of the best perennials to add vibrant shades to the late summer garden. Many of these plants are North American natives, and others come from around globe – but all seem to flourish when the heat is on!
ANISE HYSSOP (AGASTACHEFOENICULUM) Anise hyssop, also known as butterfly mint, is a fragrant perennial with upright flower spikes that bloom from June to September. Traditional varieties have blue, lavender, or purple blooms, but new ones include bold colors such as orange and red. Native to the plains and prairies of North America, anise hyssop is hardy in USDA Hardiness Zones 4-9. As a perennial, it spreads by rhizomes, and in colder climates it can be grown as a self-seeding annual. It grows easily in soil of average fertility, full sun, and medium to dry moisture conditions. Drought tolerant once established, it’s also deer and rabbit resistant – but very attractive to bees, butterflies, and hummingbirds. You can use cut flowers in fresh and dried arrangements, and the plants make attractive additions to beds and borders, butterfly, herb, and cottage gardens, or in naturalized settings like meadows or wildflower gardens.
AUTUMN JOY STONECROP (HYLOTELEPHIUM ‘HERBSTFREUDE’/SEDUM SPECTABILE ‘AUTUMN JOY’) Blooming from August to October, ‘Autumn Joy’ stonecrop is a clump-forming herbaceous perennial with large, flat heads of tiny, rosy red flowers. Upright stems grow 18 inches to 2 feet tall with succulent, fleshy leaves. Buds first appear pink, change to red as they open, and finally turn a coppery shade as they die. Stonecrop are drought-tolerant natives to Asia, Europe, and North America, hardy in Zones 3-8, and get their name from their habit of growing in stony ledges and rocky outcrops. ‘Autumn Joy’ prefers soil of average to poor fertility, dry to medium moisture, excellent drainage, and full sun. Attractive to bees and butterflies, ‘Autumn Joy’ can be used in the front of beds and borders, grown in alpine or rock gardens, planted en masse, or grown in containers. Left in place, they also add interest to fall and winter gardens.
BALLOON FLOWER (PLATYCODON GRANDIFLORUS) Balloon flower is an eye-catching, clump-forming perennial that gives a cheerful display of color to the late summer garden. Mature clumps grow from 1 to 2.5 feet tall, and young buds swell like balloons before bursting into bell-shaped flowers. Eye-catching in shades of blue, pale pink, and white, they flower from June to August. A native to the slopes and meadows of East Asia, balloon flower is hardy in Zones 3-8 and enjoys a full to partial sun location. Aside from average soil and medium moisture requirements, it’s largely self-sufficient and requires little maintenance. Balloon flower also makes addition to the cutting garden, and it’s deer resistant as well. Use it to best effect in borders, containers, edging, and rockeries.
BEE BALM (MONARDA DIDYMA) Bee balm, or wild bergamot, is a tall, attractive perennial with whorls of tubular flowers that add a bold punch of color to the late summer garden. Fragrant plants grow 2 to 4 feet tall with sassy, mop-top blossoms in colors of burgundy, lavender, pink, red, and white that bloom in July and August. Hardy in Zones 3-9, it’s endemic to moist bottomlands, woods, and streambanks of eastern North America. Bee balm prefers humus-rich, well-draining soil with medium to wet moisture levels in a full to partial sun location. Deer and rabbit resistant, it’s attractive to bees, butterflies, and hummingbirds. Striking when massed in drifts, plant in borders, cottage and rain gardens, and in naturalized plantings.
BLACK-EYED SUSAN (RUDBECKIA HIRTA) Black-eyed Susan is a cheerful wildflower renowned for its showy, daisy-like flowers in shades of orange, red, or sunshine yellow. Floret petals are anchored with a chocolate-brown center disk, and flowers bloom from June to September. Indigenous to central and eastern North America, black-eyed Susans grow best in well-draining or sandy soil enriched with organic compost, medium moisture levels, and a full sun location. Drought resistant once established, they’re hardy in Zones 3-7 and grow from 1 to 3 feet tall. Perfect for the cutting garden, they’re deer resistant, attractive to butterflies, and small songbirds enjoy the seeds in fall. Use their bright color to best effect in beds and borders, cottage or wildflower gardens, large containers, or in mass plantings.
BLUE CARDINAL FLOWER (LOBELIA SIPHILITICA) Blue cardinal flower is a clump-forming, herbaceous perennial with stiff, unbranched stems 2 to 3 feet in height. The stems are topped with terminal racemes of tubular flowers in shades of light to dark blue that bloom from July to September. Native to moist low meadows, woodlands, and stream and spring banks of central and eastern North America, it’s hardy in Zones 4-9. It requires a full sun to part shade site, humus-rich soil, and medium to wet moisture conditions. Deer resistant, blue cardinal flower is well-suited to beds and borders, rain gardens, perennial beds, native and woodland settings, and moist areas, like beside ponds or streams.
CHRYSANTHEMUM (CHRYSANTHEMUM) For reliable late season performance, chrysanthemums are available in a huge selection of colors, forms, and sizes. Blooming from August to November, flowers have ray florets, with numerous cultivars bred for multiple rows of florets in different shapes – from tubular to fringed. Colors are almost unlimited and come in shades of lavender, orange, red, white, and yellow. A native of China, this herbaceous perennial has been cultivated for millennia. It grows best in fertile, humus-rich and well-draining soil, with consistent moisture and full sun exposure. Hardy in Zones 5-9, mums appreciate a winter mulch in colder regions. Chrysanthemums attract butterflies, and are deer and rabbit resistant. They are most effective in mass plantings, at the front of mixed and perennial beds and borders, and in containers or windowboxes.
DAHLIA (DAHLIA) Dahlias are tuberous rooted perennials with a large variety of colors, shapes, and sizes ranging from 1 to 6 feet tall. They flower from July to September. The pinwheel-shaped blossoms are categorized into 10 different groups to distinguish among the many flower types, such as cactus, decorative, pompon, and waterlily. Sizes vary greatly as well, from compact patio cultivars to ones with huge, dinner-plate-sized blooms. Native to Mexico and Central America, dahlias are hardy in Zones 8-11. In colder regions, the tubers need to be dug up in the fall and stored, then planted in the spring and grown as annuals. Dahlias enjoy full sun with some afternoon shade in hot regions. Plant in well-draining, compost-rich soil, with a medium moisture level. Dahlias make an outstanding option for cut arrangements, and are well-suited for beds, borders, containers, and window boxes.
ECHINACEA / CONEFLOWER (ECHINACEA PURPUREA)Echinacea, also called coneflower, is a clump-forming perennial with purple, daisy-like flowers that put on a showy display from June to September. It grows 2 to 5 feet tall and reblooms readily, with blossoms forming on stiff, multi-branched stems clad with broad, dark green leaves. Indigenous to eastern North America, echinacea is hardy in Zones 3-9 and easily grown in well-draining soil of average fertility, dry to medium moisture, and a full to part sun location. However, this plant is wonderfully adaptable and tolerant of harsh conditions, including drought, heat, humidity, and poor soil. Echinacea is a good choice for freshly cut or dried flowers. Deer and rabbit resistant, it’s also attractive to butterflies and other beneficial creepy-crawlies, and migrating songbirds will visit seedheads in fall and winter. It makes an attractive addition in mixed and perennial beds and borders as well as native or naturalized areas, and is stunning when planted in masses with yellow black-eyed Susans.
HELENIUM (HELENIUM AUTUMNALE)If it’s vibrant, warm colors you want, helenium produces masses of daisy-like blooms in rich shades of orange, red, and yellow. Sun lovers, these erect, clump-forming plants that are also known as sneezeweed grow 3 to 4 feet tall, adding terrific interest from August to October. Native to Central and North America, helenium grows best in soil of average fertility amended with organic material, medium to wet moisture, and full sun. Hardy in Zones 3-8, it is intolerant of dry soils. It also benefits from being cut back in late spring to encourage branching and more flowers. Helenium attracts butterflies, and winter birds enjoy the seedheads, but deer avoid it. Use it in mixed and perennial beds and borders, cottage gardens, naturalized areas, and in areas with moist soil.