Green Thumbs Up: Fall-blooming favorites for the sunny border

Suzanne Mahler

As the steel-gray cloud cover gradually parted after several days of drenching rains, gardeners emerged to assess the damage to their wind-swept landscapes.

While many perennials tend to flop and sprawl at season’s end, the recent barrage of storms has left many plants battered and broken. I usually delay major cutting back of my perennial borders until after the first few hard killing frosts, but much of the crushed vegetation required immediate attention to ensure light and air could reach the plants buried beneath the debris.

As I hauled a tarp laden with refuse along a damp path that leads to my mountainous compost heap, I paused to squeeze a swollen seed capsule of the jewelweed happily growing in the moist, rich soil.

A favorite wildflower since my childhood, this ever-present member of the Impatiens family, also known as spotted touch-me-not, brings back fond memories of my carefree youth. The slightest touch on the tip of a very ripe seedpod sends seeds catapulting in all directions as the fleshy pod curls up once its seeds have been dispensed.

Its dangling, bright orange, tubular flowers are a favorite of the hummingbirds and it is said that when a killing frost blackens this plant, these tiny birds begin their long journey south. If the foliage is picked and held under water, the source of its common name of jewelweed becomes apparent, as the leaves shimmer, appearing to be made of polished silver.

Once crushed stems were clipped and removed, the gardens regained a fairly respectable appearance revealing many fall-blooming favorites. Few rival the ease and beauty of the carefree sedums.

Commonly known as stonecrop or live-forever, this broad genus of succulent plants includes upright, clump-forming types ideal for the middle of the border and trailing, stoloniferous varieties suitable for the front of the garden. Although the majority of sedum family members are not too fussy about their growing conditions, most favor full sun in well-drained, sandy soils.

Sedum "Autumn Joy" provides an especially long season of interest. Its fleshy, gray-green leaves appear on unbranched stalks topped by broad flower heads that resemble broccoli in July and gradually produce pink, star-shaped flowers in late summer.

As the fall progresses, the flattened domes acquire a deeper tone of reddish-bronze before turning a warm copper which persists throughout the winter as snow collects on the stiff seed heads.

Additional upright varieties include sedum "Brilliant" and S. "Neon," which bear electric, purplish-pink clusters, and sedum "Matrona," which exhibits dramatic, reddish-purple stems and leaves topped by massive flower heads producing a multitude of star-shaped, dusty pink blooms.

Many new cultivars, including S. "Black Jack," offer leathery, deep purple foliage that provide handsome accents throughout the growing season accented by deep pink flowers during the fall season.

For the front of the border, look for S. "Vera Jameson," S. "Bertram Anderson," S. sieboldii and S. "Angelina." Sedum "Vera Jameson" and S. "Bertram Anderson" form wide mounds, 8-inches tall, of handsome, rosy-purple leaves, their foliage color intensifying as the temperatures cool down, topped by small clusters of rose-pink flowers. Sedum sieboldii offers attractive blue-gray leaves rimmed with a thin, rosy band, complemented by pretty pink flowers in autumn.

Sedum "Angelina" has quickly become my personal favorite. This quick-growing evergreen sedum is stunning throughout the year with needle-like, golden-yellow foliage in springtime that becomes chartreuse during the summer months. As temperatures fall, the tips of the succulent needles take on a reddish-orange tinge that persists throughout the winter months.

Hardy fall-blooming asters offer a wonderful diversity of heights and colors, all characteristically producing a profusion of single or semi-double disk flowers with yellow centers in vibrant tones of rich royal purple, glowing pink, vivid raspberry and glistening white.

Although somewhat coarse in appearance, especially after several years in the garden, their fantastic floral display during the fall season more than compensates for their occasionally weedy demeanor. Pinch young shoots regularly until mid-July to keep plants compact, bushy and increase the quantity of flowers. Division every two to three years in early spring is advisable to rejuvenate woody clumps and reduce their tendency to wander. These native perennials perform best in moisture-retentive soils.

Similar in appearance to the asters, Boltonia "Snowbank" is an especially lovely addition to the sunny border. Billowing clouds of tiny white daisies appear during the fall season on upright stems 3 to 4 feet tall, smothering the attractive blue-green foliage that is handsome throughout the summer months. The cultivar "Pink Beauty," with pale pink flowers, tends to be more open and prone to flopping but adds a light, airy presence to the fall garden.

Several members of the Joe-Pye Weed family (Eupatorium) provide welcome early autumn color. Eupatorium "Chocolate" is particularly attractive with dark bronze purple leaves and clusters of puffy white flowers that appear in clusters atop 3 to 4 foot stems.

Its relative, E. coelestinum, commonly known as hardy Ageratum, has a tendency to spread rather rapidly, but the fabulous display of showy lavender-blue blossoms during the fall season are worth a little annual thinning. Moist soils in sunny to partially shady locales are preferred. 

Add a few of these hardy, low maintenance performers to brighten the sunny border in autumn. When combined with the lingering blooms of roses, Russian Sage, and members of the Rudbeckia family, the declining foliages of early blooming perennials are all but forgotten. In addition to their spectacular color, these sturdy fall-bloomers are an irresistible lure to multitudes of bees and butterflies.