Extension Master GardenerSM Volunteers of Buncombe County

Perennials & Biennials

Fall Flowers: Asters Are a Charming Alternative!

As autumn unfolds, ornamental gardens may look a little bedraggled as summer blooms fade and go to seed. That’s when fall asters can provide a burst of color and interest! There is still time to plant these long-flowering and long-lived perennials.

Recommended asters
Two native aster species pack a particular punch: aromatic/oblong-leaved aster (Symphyotrichum oblongifolium) and blue wood/common blue aster (S. cordifolium). Both species have yellow disc-shaped flowers surrounded by rayed petals in shades of blue and purple, while their foliage and height differ.

Aromatic/oblong leaf Aster
    • S. oblongifolium has narrow leaves that get smaller as they climb the stem; both leaves and stems are covered with short hairs. Usually less than 20 inches tall, it has rigid stems and lots of branches, and is fragrant when crushed. Some of the more reliable, popular aromatic aster cultivars are:
        • ‘Fanny’,
        • ‘October Skies’,
        • ‘Raydon’s Favorite’.
    • S. cordifolium has sharply toothed leaves on smooth, upright arching stems 3 to 4 feet tall—the upper leaves are oval, while the lower are heart-shaped. Cut the stalks back in
      Wood Asters

      mid-summer to form denser mounds. Deadhead to prevent unwanted seeding! Less commonly available in nurseries, there are some blue wood aster cultivars, but these are not necessarily more desirable than the species:

        • ‘Avondale’,
        • ‘Photograph’

Although all these asters have some susceptibility to powdery mildew and aster wilt, they don’t have serious pest or disease problems, deer and rabbits ignore them, and they are drought- tolerant once established.

Euptoieta claudia (variegated fritillary) on aromatic aster

Featuring asters in your fall garden
Plant asters in formal flower beds—or in naturalized areas. Their soft colors blend well with other autumn flowers, such as goldenrods (Solidago spp.) and perennial fall sunflowers (Helianthus spp.) and are a noteworthy alternative to ubiquitous fall mums. They are an abundant late-season source of nectar and pollen for bees and butterflies, too!

Aromatic asters work especially well in mass plantings along walkways, where you can appreciate their balsam-like fragrance. Plant in full sun areas with well-drained soil and good air circulation. The showy small purple flowers have a long bloom season, lasting from late summer until the first frost.  They spread by wind-dispersed seeds or underground stolons. To keep them from spreading too aggressively, deadhead often and divide in spring to disrupt root growth.

Blue wood aster prefers shade and moist, well-drained soils, thriving at woods edge or along stream banks. Deadhead to avoid unwanted spread.

Article by Buncombe County Extension Master GardenerSM Intern Anne Spruance

For more information:
Aromatic aster: https://plants.ces.ncsu.edu/plants/symphyotrichum-oblongifolium/
https://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/mdpmcfs9053.pdf

Blue wood aster: https://plants.ces.ncsu.edu/plants/symphyotrichum-cordifolium/
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a78 8

Goldenrod in the Garden: Dispelling the Allergy Myth

If late summer and autumn allergies—known as “hay fever”—affect you, you are not alone! Millions of Americans suffer from seasonal runny nose and itchy, watery eyes. Much of this allergic reaction is blamed on goldenrod and ragweed, when, in fact, only ragweed spreads irritating pollen—goldenrod does not! Goldenrods (Solidago spp.) and ragweed (Ambrosia spp.) mature in late summer; but the showier goldenrod is insect-pollinated, not wind-pollinated and that’s what makes the difference.

Goldenrod meadow_by BLeonard_BCEMGV
Fall meadow dressed in goldenrod

Ragweeds are the villains!
Ragweeds are annual native weeds found in cultivated areas, as well as along roadsides and meadows in heavy soils. In early spring, common ragweed’s (A. artemisiifolia) first leaves are opposite but become more deeply dissected and arranged alternately as the plant matures. It can grow to 4 feet tall. It produces only inconspicuous flowers of nondescript color, but in early autumn, breezes distribute clouds of allergy-causing pollen as we seek to enjoy the late summer and early autumn. If you learn to recognize its leaves, it is easy pull any time before it flowers, and mowing will keep it under control—you will be shearing off any flower stalks before they bloom. Note that we also have giant ragweed (A. trifida) in our area that also produces irritating pollen. It is much taller—up to 16 feet!—and has opposite leaves with 3 to 5 large lobes and flowers much like common ragweed.

Welcome goldenrod to your garden!
Goldenrod is a native herbaceous perennial in the aster or Asteraceae family that presents dazzling displays of brilliant yellow flowers in open meadows and roadsides. These bright yellow flowers hold sticky pollen that attract bees, butterflies, and other insects until early frost. As the floral display matures, birds flock onto upright stems to enjoy the seeds.

Although sometimes viewed as weeds, these wildflowers represent a very diverse collection of many species:

  • They range in size from little more than 12 inches to 6 feet tall.
  • Some spread aggressively, while others form well-behaved clumps.
  • In addition to soft plumes, goldenrods’ yellow flowers can be spiky or even zig-zagged!
  • There are species adapted to many habitats, from salt marshes, to swamps, prairies and woodlands.
Goldenrod (Solidago)_Leonora (Ellie) Enking_CC BY-SA 2.0_Flickr
Goldenrod in the garden

Those found in our mountains are a welcome addition to perennial gardens, combining well with Echinacea, ironweeds (Vernonia spp.), Joe Pye weeds (Eutrochium spp.), Rudbeckias, taller sedums, and ornamental grasses to add vivid color to the late summer garden. They are also lovely additions to floral arrangements. Some local natives include:

  • Early goldenrod (Solidago juncea) starts blooming in July and is drought-tolerant.
  • Sweet goldenrod (Solidago odora) has anise-scented shiny leaves, reaches only about 2 to 3 feet tall and has a well-behaved clumping habit.
  • Common goldenrod (Solidago altissima altissima also known as Solidago canadensis var. scabra) is a tall (up to 6 feet) plant that spreads aggressively by underground rhizomes, which can be an advantage in controlling erosion, even on steep slopes.

Goldenrods are subject to very few diseases, and although you may see some galls, spider mites and lace bugs, deer typically ignore them.

So, as September arrives, bringing the first falling leaves, hints of coolness in the air, and breezes carrying pollen, don’t be concerned about goldenrod. It’s a harmless beauty!

What to do about allergies?
Donna Teasley, Extension Agent, recommends ways allergy sufferers can keep symptoms to a minimum:

  • Avoid hanging laundry to dry outside.
  • Hire someone to mow the lawn during late summer.
  • Keep bedroom windows closed at night.
  • Keep car windows rolled up while driving.
  • Stay indoors on windy days and at peak pollen hours—early morning and late afternoon.

While these suggestions can certainly help allergy sufferers cope, one final thing we can do to lift our spirits as we gaze outdoors or ride along is to take time to enjoy the goldenrods!

Article written by Mary Alice Ramsey, Extension Master GardenerSM Volunteer.

More information
Read about different types of goldenrod, from the wildflower to cultivars for the garden.
NC State Extension publications

Common Ragweed
by Charles Peacock, Professor and Extension Turfgrass Specialist
NC State Extension

Giant Ragweed
by Dr. John Hilty, Illinois Wildflowers

Allergy Sufferers Alert
by Donna Teasley, Extension Agent, Burke County, NC
NC Cooperative Extension

Peonies for Memorial Day

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Peonies are a traditional Memorial or Decoration Day flower, used to adorn the graves of those who died in service to our country. These lush blossoms captivate many gardeners and there are only a few details to master to grow your own.

Peonies are long-lived perennials, but they bloom only once each year, near the end of May.

Traditional peony “bushes,” are herbaceous species, dying to the ground each winter but there are also shrubbier varieties, Both are available in a range of flower colors, mostly pinks, reds and whites. Their flower forms range from a simple single bloom to fully double blossoms. Hybrid crosses between the herbaceous and tree peonies, called intersectional varieties, may be more disease resistant and require less staking than herbaceous peonies, are also available.

Can you grow herbaceous peonies here? Yes, but Peonies don’t do well in hot climates, and at the same time need full sun to bloom best. Read the description of the plant carefully. Choose the site and varieties with lower “chilling hour” requirements for the South.  Many newer varieties are bred for much colder climates. Locate in a well-drained site with a neutral pH (6.0 to 7.0).

Fall planting is preferred, allowing peonies to establish their root systems before the stresses of warm weather;.  Plant bare root peonies, transplants or divisions only in the fall. Be sure that the “eyes” are no more than 2 inches below the surface.  Too much nitrogen fertilizer may also interfere with flowering; fertilize in early spring with 5-10-10.

Don’t worry if ants overrun the swelling buds. Ants are neither necessary for, nor harmful to, opening flowers. They are simply attracted to the sticky, sweet secretions.

Article written by Debbie Green, Extension Master Gardener Volunteer.

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Buncombe County Extension Office
49 Mount Carmel Road
Asheville, NC 28806
Helpline 828-255-5522

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