Perennials are a staple of the garden, providing colorful blooms that draw our eyes to various parts of the landscape. Unfortunately, these plants often present a problem. The flowers that captivate us quickly fade into nothing more than a shriveled lump of petals. It's hard to imagine a garden without perennials, but this drawback often steers people away from these beautiful plants in favor of annuals, which may bloom longer but come with their own set of downsides.
Happily, we can find perennials with a long bloom period. These options reduce maintenance because they do not require deadheading, and unlike annuals they needn’t be replanted each year. Often they help support pollinators, too. Here are some of my favorite perennials for extended color in the garden. Some you may recognize, but while known they still merit recommendation. Others are less familiar. Arrange these long-blooming perennials in drifts to best embellish the garden and distract from more fleeting beauties. A few I’ve listed perform very well in the shade, where it can be most challenging to find flowers post spring.
‘Rozanne’ cranesbill (Geranium ‘Rozanne’)
As I write this story in late fall, my Wisconsin garden has finished blooming and its perennials are fading into dormancy—but then there's 'Rozanne'! This hardy geranium, or cranesbill, started flowering early July and it still showed a heavy cover of purple blossoms on Halloween. 'Rozanne' is a sterile hybrid, giving the plant energy to continue blooming and preventing reseeeding. It has a sprawling habit, staying below two feet tall and but reaching three feet wide. It looks stunning among roses and tall perennials, where it can spread around the base of the plants.
‘Rozanne’ grows in full sun or part shade and any soil type. The more sun it has, the tighter its habit will remain and the heavier it will bloom. It prefers even moisture but can take periods of drought once established. A quick late summer shearing can be helpful to refresh the foliage ahead of fall. USDA Zones 5–8.
Dwarf bleeding hearts (Dicentra eximia and D. x‘Luxuriant’)
These dwarf bleeding hearts are tiny compared to the common species (Lamprocapnos spectabilis), but their blooms last longer. In my garden, these bloom from May until October if they receive consistent moisture. They may go dormant during summer in warmer climates, but they will regrow and bloom again when cooler weather returns.
Dicentra eximia is native to the eastern United States, growing up to 18 inches tall and wide and blooming in light lavender-pink. ‘Luxuriant’, a hybrid that tolerates heat, grows to the same size but with larger foliage and flowers, which also provide a darker hue. Both plants prefer a location with part shade and moist, fertile soil. When happy, they can gently spread. Zones 3–9.
Yellow corydalis
(Cordyalis lutea)
This little groundcover grows almost anywhere in the shade. The small yellow flowers appear in late spring and continue until frost. The delicate looking foliage resembles that of bleeding hearts and makes a beautiful edging along shady pathways. A mounding perennial, it grows to a little over a foot tall and wide.
Gardeners who grow yellow corydalis often find volunteers growing in the nooks and crannies of their garden, as this plant likes to self-seed. However unwanted plants are easy to pull. This plant is happiest (and most likely to pop up) in part to full shade and rich, moist but well-drained, gravelly soil. Its preference for sharp drainage makes it a good subject for shaded rock gardens and for planting in the gaps in a stone wall, especially in cooler regions. Zones 5–7.
Walkers Low catmint (Nepeta racemosa ‘Walker’s Low’)
The award-winning 'Walker’s Low' is well known among gardeners who’ve sought a cool-hued, soft-textured perennial with drought tolerance. This durable plant is covered in pale lavender-blue blooms in early summer and it will lightly rebloom until fall. Its seeds are sterile, meaning it won’t spread through the garden.
A complaint some have of this catmint cultivar is its tendency to flop. This problem can be avoided by restricting its planting to drier soil and shearing the stems by half at midsummer. This catmint reaches about three feet tall, so there’s plenty of height to accommodate this treatment; the name ‘Walker’s Low’ doesn’t refer to the plant’s size, but to the garden in Ireland where it was first found, in the 1970s.
In addition to good drainage, provide this perennial with full sun or part shade. It survives moderate drought once established. To bolster winter hardiness, delay cutting the spent stems back until early spring. Zones 4–9.
Fall anemones
(Anemone xhybrida ‘Robustissima’ and ‘Andrea Atkinson’)
Japanese anemones serve as effective groundcovers in summer, but they shine in fall. A trial performed at the Chicago Botanic Garden put ‘Robustissima’ and ‘Andrea Atkinson’ among the longest-blooming anemones, with each flowering there into November. 'Robustissima' is a popular cultivar with light pink flowers and a vigorous growth habit, while 'Andrea Atkinson' has white blooms. Both plants are plants are stunning when grown in mass. Their mounded foliage remains low, but their flowering stems can reach four feet tall, providing flexibility in placement.
Japanese anemones tend to spread from their roots, so plant them in areas where they have room to expand. They perform well in part shade areas, although ‘Robustissima’ is quite tolerant of more sun. Both cultivars prefer moist, well-drained soil. Zones 4–8.
Virginia spiderwort
(Tradescantia virginiana)
Spiderwort is unique for several reasons. Each blue-violet flower lasts only a day, and the petals often close in the afternoon, making this plant most attractive in the morning. Despite the brief life of each flower, the overall bloom lasts from late spring to midsummer.
Spiderwort’s blade-like foliage and eyecatching blossoms create an exciting contrast; passersby might mistake this perennial for a very unusual, three-foot-tall grass. ‘Sweet Kate’, a cultivar, further ups the interest with its bright chartreuse leaves, a departure from the deep green of the species.
After midsummer, the foliage begins to die back. For this reason, site spiderwort near companions that can mask the yellowing leaves and fill the gap they leave. A native of much of the eastern United States, where it grows in open woods, this is a plant for areas with moist soil and part to full shade. It also tolerates short periods of drought and inundation. Zones 4–9.
‘Zagreb’ threadleaf tickseed
(Coreopsis verticillata ‘Zagreb’)
This trusted perennial has golden flowers from midsummer until fall, in a much deeper shade than the related ‘Moonbeam’, which does not bloom quite as long. Gardeners sometimes struggle to find reliable coreopsis, but 'Zagreb’ is exceptionally durable, tolerating heat and dry soil. After the initial flush of bloom, the plant lightly reblooms through autumn. The foliage is attractive, too, with its fine texture. 'Zagreb' grows about 18 inches tall and wide and looks best planted in a group.
This is a plant for full sun and average to poor soil. It can tolerate some drought once established. With consistent moisture and richer soil, you may find ‘Zagreb’ spreads from both seed and its roots. These conditions can also cause lax growth that necessitates shearing back in later summer, which will also reduce reseeding. Zones 4–9.
Russian Sage
(Perovskia atriplicifolia)
You can’t miss the purple blooms and finely cut foliage of Russian sage. On a late summer day, these plants offer a drift of color as many others begin to wind down. This semi-shrub offers a number of cultivars, ranging from the under-three-feet-tall ‘Denim 'n Lace' to the four-foot tall ‘Suberba’. New varieties tend to be compact and upright, a real improvement over the species, which tends to flop. Russian sage is a stunning companion plant for other fall-blooming perennials.
This plant requires full sun, which prompts both heavy flowering and compact growth, and sharp drainage. It takes drought in stride and needs only an annual cutting back at the end of winter. Zones 5–9.
‘Goldsturm’ black-eyed Susan
(Rudbeckia fulgida var. sullivantii ‘Goldsturm’)
The classic 'Goldsturm' rudbeckia has been used heavily since its introduction in 1937. The daisy-shaped blooms first show up in midsummer and keep on coming into fall. Several new black-eyed Susans have been introduced recently, but ‘Goldsturm’ still has much to offer in the garden, including durability and four-inch-wide, long-lasting blooms. It grows two to three feet tall and nearly as broad, with an upright stance.
Grow ‘Goldsturm’ in full sun and consistently moist soil, where it may gently spread by rhizomes. Over time it can come to resist short periods of drought, although its parent species hails from damper sites in the Mid-Atlantic and Midwest. Zones 3–9.
All images courtesy of Walters Gardens except Anemone robustissima 'Andrea Atkinson' by F. D. Richards/CC BY-SA 2.0; Spiderwort by Michele Dorsey Walfred/CC BY 2.0; Dicentra eximia by Patrick Standish/CC BY 2.0; Corydalis lutea by David J. Stang, source: David Stang. First published at ZipcodeZoo.com, CC BY-SA 4.0.
___________
