Late Blooming Perennials
The hot, dry late summer weather can be harsh on our gardens. Many plants suffer from heat stress, too little or too much rain, and struggle to flourish. However, there are several flowering perennials that keep performing even in late summer into the fall. Here are a few perennials to consider adding to your gardens for some late summer color.
Bee Balm (Monarda didyma) is a deciduous perennial in the mint family. It is native to North Carolina mountains but will grow well in Eastern North Carolina. Bee balm reaches a height of 2 to 4 feet and has scarlet flowers that bloom in summer for up to 8 weeks. Bee balm can provide summer to early fall color in perennial borders, cottage gardens, native/pollinator gardens, or in naturalized plantings
There are cultivars available of bee balm that provide pink to purple and white flowers. Bee balm is a great flower to attracting bees, butterflies, and hummingbirds. Bee balm can spread easily by underground stolons, so seedlings may have to be pulled up to control spread or plant can be divided as needed in Spring. It prefers moist, well-drained soils and full sun but will tolerate some shade. Powdery mildew disease can be a problem, so do not crowd plants or water overhead to help prevent powdery mildew.
Autumn Joy Stonecrop (Hylotelephium ‘Herbstfreude’ AUTUMN JOY) Autumn Joy Sedum is one of the most dependable and lovely perennial succulents that is attractive through the year. It performs best in full sun in well-drained soils. It can suffer in overly moist or fertile soils. Once established, it is drought tolerant. Autumn Joy works well in containers (indoors or outside) and planted in borders or rock gardens. In the spring, rounded, fleshy green leaves emerge. In the summer, flower buds are light pink and open to red in late summer and early fall. In the winter, browned flower heads can be considered ornamental. To maintain the bushy shape and thick stems cut or pinch plants back in early spring. Plants can be propagated by division, stem or leaf cuttings. Autumn Joy Sedum makes a good pollinator plant, especially for butterflies.
Black-Eyed Susan (Rudbeckia hirta) is a perennial that is native to the eastern United States. It can be short-lived but freely self-seeds and usually remains in the garden for years. It can even be found growing along banks and roadsides. Black-eyed Susan reaches a height of 4 feet. The flowers have a brown, domed center surrounded by bright yellow petals. It will start to bloom in mid-summer and with deadheading, continue into mid-fall. Black-Eyed Susan is fairly drought tolerant and is low maintenance. They mature rapidly in average, well-drained soil and are best in sun to partial shade with no serious insect or disease problems. They can sometimes have powdery mildew, so do not crowd plants or water overhead to help prevent powdery mildew. Black-eye Susan is great for pollinator and native gardens to attract butterflies and other pollinators.
Russian Sage (Salvia yangii) is an erect, perennial shrub that is clump-forming. Its mature size is 3-4’ tall and wide. Russian sage has blue flowers that shine from summer through fall. The flowers grow as spikes giving a cool, airy look in the garden. It is a very heat and drought-tolerant plant that is also resistant to damage by deer and has no serious pest or disease problems. Russian sage grows best in full sun and well-draining soils. Prune plants back to 4 inches in late winter or early spring for more compact growth. The foliage is grayish-green and provides some light fragrance when leaves are crushed.
False Sunflower (Helenium autumnale) is also known as sneezeweed mistakenly gets blamed for allergies because it blooms about the same time as ragweed. However the name is misleading since it does not cause allergies, but is named on historic use of the crushed dried leaves and heads to make a form of snuff that caused sneezing. The plant grows in clumps 2 to 5 feet tall from the crown. Its flowers bloom in dense clusters over a long period of time from late summer into fall. Flowers are daisy-like shaped ranging in color from pale or bright yellow to fold, warm orange, and deep red. False sunflower grows best in full sun and well-drained soils with moderate moisture. Consistent deadheading promotes more flowers and it is a great flower for attracting pollinators such as butterflies and bees. The common weedy native can be found throughout the United States in moist soils along streams, ponds, and in swamps. However, there are cultivars of Helenium that are much showier in the landscape. A couple of popular cultivars include: ‘Butterpat’ with bright yellow ray flowers with plants getting 4 feet tall or taller and ‘Moerheim Beauty’ that is one of the most well-known and popular varieties. ‘Moerheim Beauty’ blooms earlier with reddish-bronze flowers in a range of shades and seldom tops 3 feet tall.
As you enjoy some cooler fall weather, consider adding of these or one of many other late-blooming perennials to your garden and landscape to extend color through the fall season.
Jessica Strickland is an Agriculture Extension Agent, specializing in horticulture for North Carolina Cooperative Extension in Wayne County.