The Dirt / Late bloomers

Now is the time to find plants for spectacular August and September gardens



Heleniuym (Sneezeweed)

 

July gardens throughout the Northeast, especially in Buffalo, tend to be colorful. The second half of July is our gardening climax. Hundreds of gardeners invite thousands of guests to see their spectacular flowers and planters during Garden Walk Buffalo and other tourism and social events. And the colorful perennials, lush foliage, and overflowing annuals continue to perform and please homeowners and visitors alike, at least into the first half of August. 

 

But what about September and October? Are we so tired out that we let our gardens wind down as though the season is over? Or is it that many gardeners are just not familiar with superior late season high performance plants? 

 

My theory is the latter: most people shop in May and June, when the fever is upon them. They buy plants that show flowers, or that at least offer several inches of promising foliage. They ignore perennials and shrubs that perform later in summer because a) those plants don’t look like much in June and b) those plants aren’t familiar. Often, late blooming plants do not speak well on their own behalf.

 

Japanese Anemone

 

The quest for perpetual flowers

One of the eye-roll inducing requests often heard at garden centers (and wherever new gardeners congregate) is along these lines: “I would like a lot of color for the whole season. Oh, and it’s shady, and we’re going away for three weeks in late June.” 

 

Of course, people want lots of flowers. But as they learn about gardening, most folks figure out that the way to have continual flowers is to plant annuals in May or June and tend them all summer. (A few garden centers keep a supply of hanging baskets and fill-in plants during July, but not everyone everywhere can depend on this.) If you water, fertilize, and deadhead or groom the annuals, most will flower for a whole season. The most floriferous ones tend to require sunshine, too. If the garden is shady, it’s truly a challenge to fill it with full-time flowering plants.

 

 The alternative to maintaining that annuals garden: stage perennials and flowering shrubs that naturally bloom at the right time in the season. In the case of the uncolorful late summer garden, here are some winners that add excitement just when all those daylilies and daisies are fading away. You could concentrate on all these for a garden that peaks in late August through September when you’re back from vacation or when you entertain. Or you could just plant a few now, in July or early August, for a beautifying splash. These plants should be waiting for you in several of our region’s garden centers. 

 

Perrenial grass Miscanthus

 

Late-flowering perennials

These hardy perennials blossom or look their best after mid-August, and need at least six hours of full sun daily. (Comments indicate typical height, flower color, and which ones are shade-tolerant.)

 

Aconitum (Monkshood)—several species, many hybrids: mostly deep blue flowers (a rare treat in a summer garden), dark green and glossy leaves (mostly deeply divided); three to four feet tall. Poisonous, but unlikely to be tempting; accepts afternoon shade. 

 

Amsonia hubrechtii (Narrow-leaved or Arkansas Amsonia): delicate blue spring flowers, but the reason to have them is the dynamic gold, thread-leaved foliage in fall; about three feet tall. Perennial Plant of the Year 2011; shows off best in drifts. 

 

Anemone japonica (Japanese anemone): luminous, long-lasting white or pink blooms; three-point-five feet.  It spreads but pleasantly so; accepts light shade.

 

Asters: Both native and non-native offer great autumn color, mostly purple flowers; varying heights. Aster ericoides ‘Snow flurry’ is a marvelous, short edge plant.

 

Boltonia asteroides ‘Snowbank’: if you can find it, this three-point-five-foot white aster-like plant is bright and blooms through October, making pollinators especially happy.

 

Chrysanthemum: at least a hundred species of “mums” exist; many are perennials. Most people picture them as the fall-flowering balls of color sold in garden centers or farmers’ markets. (While those plants are technically hardy, they have been forced to perform so intensively that the root systems are unlikely to settle in well before winter; most don’t survive.) If you can find Montauk/Nippon daisies or new chrysanthemum cultivars to plant, plant them as early in the season as you can. 

 

Eupatorium (Joe-Pye weed): both native species and cultivars are butterfly magnets; mauve or white flowers, ‘Chocolate’ with wine-colored leaves. Read tags for height and degree of spreading.

 

Helenium autumnale (Sneezeweed—although it does not produce allergens; also called Helen’s Flower): orange, copper, gold, maroon colors and patterns; most about four feet tall. 

 

Hibiscus moscheuto (hardy Hibiscus): dramatic dinner plate-sized flowers on four to six-foot plants. Stalks die back in winter and appear dead until sometime in late May, so do not dig it up!

 

Phlox paniculata (garden phlox): a staple for summer gardens, with several heights and colors; many about four feet tall. Frequently develop powdery mildew but resistant species can be found (or just plant them behind three-foot plants so the foliage is hidden). 

 

Physostegia virginiana: ‘Miss Manners’ (Obedience plant): pink physostegias are notorious for vigorous spreading, but are great if you have room; white flowering ‘Miss Manners’ is manageable;  about twenty inches tall.

 

Rudbeckia ‘Herbstonne’: prolific yellow flowers beginning in July; six to seven feet tall. For later flowers and sturdier stems, cut back by half in early June. Shorter Rudbeckias (Black-eyed Susans) are well known and long flowering.

 

Sedums: from tiny ground-covering cultivars (‘Dragon’s blood’ and ‘John Creech’) to twenty-inch ‘Autumn Joy’ and ‘Matrona,’ there are sedums of all sizes for all sunny situations; most offer great fall color and important nectar for pollinators. 

 

Solidago (Goldenrod): considered a field weed by many, goldenrods are treasured in Europe. Now cultivars such as ‘Fireworks’ and ‘Golden Fleece’ are available as fine perennial specimens; typically three feet or taller.

 

Vernonia noveboracensis (New York Ironweed): stunning, huge native plant, thrilling to pollinators and observers for its magenta flowers; six to eight feet tall. The cultivar ‘Iron Butterfly’ has threadlike leaves and pretty purple flowers; less than three feet tall 

 

Ornamental grasses are obvious contenders for roles in a summer-to-fall garden because of their colorful seedheads, graceful forms, and red or patterned leaves. Consider these, comparing height and spread of the many cultivars: Panicum, Calamagrostis, Carex, Molinia, Miscanthus, and Pennisetum. Plant ornamental grasses in permanent locations, as most become nearly impossible to move after three years.

 

Callicarpa (Beautyberry)

 

Shrubs for flowers and berries

Many shrubs—including Itea, Rhus, and many viburnums—offer wonderful foliage color in autumn—but don’t forget that some shrubs provide more flowers (or colorful berries) per plant than any known perennial, often with less maintenance. Add these to the late-performing garden:

 

Aronia (Chokeberry): native plant with decorative red or black berries along with startlingly bright red foliage; part shade okay; cultivars four to six-feet tall.

 

Caryopteris (Bluebeard): lavender-blue flowers and either gold or bluish-gray leaves; attracts butterflies; two to three feet.

 

Callicarpa (Beautyberry): magenta berries are stunning; dies back in winter; to about four feet. (In Zone 6, try the pink-berried cultivars.)

 

Ilex verticillata (Winterberry): has bright red berries long before winter; requires male and female plants; cultivars of several heights.

 

Vitex: called a “summer lilac” for the large, abundant bluish-purple, pointed flowers (not a true lilac); in cold climates it dies back in winter and may reach only a few feet tall; in warmer climes, it’s very tall.

 

Aronia (Chokeberry)

 

If the summer garden disappoints…

Western New York has a temperate climate that usually provides comfortable summers with abundant sunshine and just enough rainfall. But just in case summer lets us down someday—or you take a cottage in the mountains or at the shore for two months—isn’t it nice to know that a garden can be its very best in September? Get to know the late bloomers.        

 

Sally Cunningham (CNLP) is a former master gardener and extension educator, author (Great Garden Companions), and writer for the Buffalo News and Spree.  She is the local arrangements chair for the national Garden Writers Association conference in Buffalo (August, 2017), consultant at Lockwood’s Greenhouses, and Tour Director for GreatGardenTravel, a division of AAA/Horizon Club Tours. 

 

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