Category Archives: plants for pollinators

Native Plants for Autumn Interest

By Jonathan Chesler

Assistant to the Head Gardener

As summer hits its high arc and the days grow technically but as yet imperceptibly shorter, Northeastern gardens are in full flush and bloom. Pick-your-own produce places pop up and roadside farm stands fill out with signs for ‘Native Corn’ and ‘Native Tomatoes.’ Despite the horticultural inaccuracy found on those placards and in other cases, it’s noteworthy that a plant’s native status is emphasized as an important selling point. True, while everything is native to somewhere, for our purposes, native plants are those that have been found in the Northeast (New England) from pre-Colombian times.

The white-flowering Coneflower, Echinacea purpurea ‘White Swan,’ and Rudbeckia fulgida sullivantii ‘Goldsturm’ are both improved natives, and they’re both popular with pollinators.

So why the interest and excitement over natives? Firstly, native plants ask for few resources upon seeding or planting them, and they also give back in abundance. As these plants have co-evolved with native butterflies, moths, birds and the like, they are recognized as sources of food, and good food at that. It’s not by coincidence that White Flower Farm’s Butterfly Magnet Collection, Monarch Butterfly Collection, and Pollinator Garden for Sun heavily favor native cultivars; e.g. Liatris, Phlox, Echinacea, Milkweed, Agastache, and Coreopsis (in no particular order).

Aster ‘Monch,’ an improved variety of our native Aster, begins blooming earlier than most of its relatives. The lavender flowers arrive in our area around July, and they keep on coming until frost.

When properly placed and established, native plants are vigorous players that usually outperform newcomers when the vagaries of nature throw drought, inundation, disease, and predatory herbivores their way. Not to say that they cannot be affected and even succumb to the aforementioned, but they often can overcome such problems with minimal care. This leads us to the next point: native plants generally don’t need as much water, fertilization and disease control as non-natives. This leaves you more time to fuss over other areas of the garden, or perhaps a chance to sit back and enjoy!

Finally, despite increasing popularity, natives and native cultivars are uncommon enough to elicit surprise, yet they’re entirely familiar and fitting in our gardens. No matter what kind of environmental conditions you have in your garden, or what kind of color or effect you’re looking for, you’re sure to find a native that excels in one or more areas. Dry or wet, shady or sunny, small or expansive — there are plenty of choices that are horticulturally interesting in leaf, form or flower. What follows here are some native highlights best seen in fall, before New England’s lakes and ponds release their stored summer heat and before morning mist and leaf peepers displace the snowbirds heading south.

Lonicera sempervirens ‘Major Wheeler’ is an improved variety of the straight Honeysuckle species, our native Lonicera sempervirens. Hummingbirds love the tubular flowers on this vine. You’ll love the color that persists from summer into fall.

While correlation does not imply causation, native fall flowers seem to hit their stride just as ‘Back to Skool’ advertisements begin to appear. Liatris, Coreopsis, and Monarda (Bee Balm) recede as Trumpet Honeysuckle, Autumn Phlox and Ox-eye Daisies continue their earlier summer shows into early autumn’s prime-time. Echinacea, Rudbeckia and Asters are in full effect. As vacations end and grumbling begins, optimistically bright Black-eyed Susans are true pick-me-ups and are as quintessentially New England as clam chowdah and apple pie.

New York Ironweed in flower at the site of the former Project Native. The tag on the butterfly is part of a study monitoring their progress in the wild. / Photo by Jonathan Chesler

The Goldenrods flower, as does Vernonia novaboracensis, New York Ironweed. White Flower Farm offers the Ironweed cultivar ‘Iron Butterfly,’ which tops out at about 3’, far below the impressive 6-8’ potential of the straight species, making it far more practical scale-wise for most gardens. It’s a strong favorite of Monarch butterflies, and the persistent seed heads fade to a rust color in the fall, giving it the common name. The seed heads are treasured by birds in the winter.

Part of the Mariachi(TM) series of compact Heleniums, ‘Fuego’ is an improved form of our native Helenium autumnale. It adds vibrant late-season color to the garden.

Another spectacular fall flower is Helenium autumnale, which is also called Dog-tooth Daisy or Sneezeweed. Beyond the straight species’ pure orange-yellow are brighter yellows and reds and oranges best found in the Mariachi™ series, which is also offered and grown here at White Flower Farm. Chelone glabra, Turtlehead, can be a late-to-the-party, white- or pink-flowered, deep green-leafed shade-tolerant plant, which, contrary to much of what’s written, can handle sun, if provided with enough water.

Eragrostis spectabilis, Purple Love Grass, appears at this time as well, along roadsides and in our new Native Garden designed by Head Gardener Cheryl Whalen.   The light and feathery, relatively low seed heads are more of a 1980’s neon pink than purple, but semantics notwithstanding, and as the Latin implies, it’s a spectacle not to be missed.

Our native Viburnum acerifolium, or Maple-leaved Viburnum, produces lacy white blossoms in summer followed by richly colored foliage in the fall. / Photo courtesy of Missouri Botanical Gardens
Maple-leaf Viburnum puts on its autumn show. The berries are inedible to humans but they’re favored by birds. / Photo by Jonathan Chesler

In addition to flowers, shrubs small and large come into their own just as signs for New England’s Fall Fairs start appearing by roadsides, framed by the aforementioned Eragrostis. Red or black, you win either way with Chokecherry roulette. The fiery red foliage is a feast for the human eye, and for many a hungry bird to boot. And while most people fend off angry birds to protect their blueberry crop, Blueberry bushes both high and low are surprisingly undervalued for their foliage, which I find even more attractive than the Chokecherries, and far superior to the invasive, thornily ornery Berberis thunbergii, more commonly known as Japanese Barberry. If you prefer the hot pink fall foliage of Barberry to the redder Blueberry, there is still a native answer – Viburnum acerifolium, Maple-leaved Viburnum. This understory shrub is eye-catching and, like the Chokecherries, its berries are inedible for humans but delicious to our avian companions.

Amsonia hubrichtii, its foliage glowing yellow in autumn, is a Southeastern native and a cousin of our Northeastern native, Amsonia tabernaemontana.

In addition to brilliant colors, there is a wide variety of natives that offers interesting foliage textures to Northeast gardeners. While many of the above have small leaves and the Amsonias in particular take fine texture quite seriously, Hydrangea quercifolia, the Oak-leaf Hydrangea, and Rubus odoratus, or Flowering Raspberry, have broad leaves and coarse texture. Both need a fair amount of room, and they tolerate or prefer light to part shade. Shade will reduce bloom size and number, but if that’s not the goal, they can fill in space very nicely. I have an Oak-leaf Hydrangea that was slammed into a lightly shaded corner quickly before the frost two years ago, but it has responded so well in form and flower that the most temporary solution became the most permanent.

Pretty Clethra ‘Ruby Spice’ adds beauty and fragrance to summer gardens. The dark green foliage turns yellow in autumn. It’s an improved form of the native Clethra alnifolia.

The Oak-leaf Hydrangea’s spectacular orange, scarlet and purple extends its seasonal interest and contrasts the lemon yellow of the Flowering Raspberry. In addition to the red and pink fall foliage described above, Lindera benzoin or Spicebush, Clethra alnifolia or Sweet Pepperbush, and Amsonia tabernaemontana or Bluestar, provide attractive yellows to brighten the fall color palette.

Rudbeckia ‘Goldsturm’ is a standout in the late summer border amid violet pink Phlox, paler pink Agastache (foreground right), the dried flower heads of Drumstick Allium (left), and globe-shaped Allium (foreground right), and Ornamental Grass.

In this New-York-minute scramble through the ancient Adirondacks, past Congregationalist churches, “Native Corn” farm stands and “Pick Your Own” pastures, I hope you’ve sensed the wide variety of available native plant material, whether you aim for sun or shade, big or small, flower, leaf color or shape, or edibility for yourselves or for friendly fauna. So explore, and indeed, pick your own!

[Editor’s note: Among the images here are plants that are not the straight species referred to in the article. Several are what is called “improved” varieties, which means they’re bred from natives with the intent of enhancing particular characteristics such as form, blossom size or color, hardiness, etc. Those who interpret “native” most strictly may wish to seek out the straight species forms of each plant.]

 

Asclepias tuberosa: Essential Monarch Food & a Whole Lot More

Asclepias tuberosa, our native Butterfly Weed, has long been a favorite in the borders, beds and meadows here at the farm. In recent years, it’s attracted significant attention as an essential source of food for Monarch butterflies who feed on it during their larval stage. (For more information about its role in sustaining Monarchs, visit the website for the Xerces Society for Invertebrate Conservation.)

This year, it was named the 2017 Perennial of the Year by the Perennial Plant Association.

Asclepias tuberosa
The nectar-rich blossoms of Asclepias tuberosa provide food for a wide variety of pollinators.

We have long encouraged plantings of Asclepias tuberosa (pronounced uh-sklee’pee-us) because, in addition to providing food for Monarchs and nectar for a wide variety of pollinators, it’s a boldly colorful bloomer that provides four seasons of interest in the garden. Hardy in zones 4 through 9S and 10W, it grows a modest 1- to 2-feet tall, making it ideal for the edge of the border. The plants produce clusters of brilliantly colored, nectar-rich orange blooms from July through September. (Asclepias tuberosa ‘Hello Yellow,’ an enhanced native variety, grows 2–to 3-feet tall and produces yellow flowers.) These plants shrug off drought, do well even in poor soil, and are deer resistant.

ASCLEPIAS TUBEROSA (YELLOW FORM)
Asclepias tuberosa ‘Hello Yellow’

As autumn arrives, Asclepias tuberosa’s seedpods add interest to borders and beds. The slim, decorative pods are filled with papery seeds. As the season progresses, the pods split open, and the seeds, which are attached to silky white parachutes, scatter in the wind. The plant’s pale, empty husks remain, and as winter settles in, the pods look magnificent coated in frost and then in swirling snow. The winter beauty of this plant is not lost on Dutch designer Piet Oudolf who included Asclepias tuberosa in his design for New York City’s High Line.

milkweeds-022-620x416_deborah-silver
Milkweed pods. Photo courtesy of Deborah Silver of Deborah Silver and Co.

A 2014 post on the Friends of the High Line blog notes: “The intricate flowers [of Asclepias tuberosa] are stars of the garden in the summer, but the empty husks of the seed pods remain an integral part of the winter garden as well. These oblong golden-gray husks are dry and slightly twisted, warped from the process of drying out. The outsides are rough and gray, with a hint of gold when the light is right. The insides are soft white, reminiscent of the silky hairs that caught the wind and carried the seeds away. These pods crown the remnant skeleton of the stem, providing a subtle, textural beauty during the deep cold of winter. These structures remind us that to High Line planting designer Piet Oudolf, ‘the skeletons of the plants . . . are just as important as the flowers.’ ”

When planting Asclepias tuberosa, be mindful of a few things. It grows best in full sun and well-drained soil (sandy soil is ideal; clay and heavily enriched soils are not). After planting, water the plant deeply then hold off until you see it begin to wilt a bit. If your Asclepias tuberosa develops yellow, chlorotic-looking leaves, it’s an indication that you’re over-watering.

Since some perennial Milkweed varieties are among the last to emerge from dormancy in spring, you might want to mark their location so you don’t plant something on top of them.

Asclepias tuberosa, zinnia zowie
Create a tone-on-tone palette by planting Asclepias tuberosa with other orange-flowering plants including Zinnia ‘Zowie! Yellow Flame.’

Design-wise, as with many additions to the garden, Asclepias tuberosa is most effective planted in clusters of three or more. To create an eye-popping contrast of colors and flower forms, showcase the bold bright orange blossoms alongside the deep purple flower spikes of Salvia ‘May Night’ and Liatris ‘Kobold.’ For a tone-on-tone effect, our head gardener has planted orange-flowering Asclepias tuberosa amid a sea of other orange bloomers such as Zinnia ‘Profusion Orange,’ Echinacea Butterfly™ ‘Julia,’ Butterfly™ ‘Postman,’ or Prairie Pillars™ ‘Flame Thrower,’ and Helenium ‘Short ‘n’ Sassy.’ In meadow gardens, the orange flowers pair beautifully with ornamental grasses including the 18”–30” Pennisetum ‘Hameln’ and the blue spiky foliage of Festuca glauca Beyond Blue™. They’re also a terrific companion for Amsonia hubrechtii, which has green needle-like foliage that turns into a cloud of yellow in fall.

Liatris spicata Kobold, Stokesia, Asclepias tuberosa
Asclepias tuberosa with the purple flower spikes of Liatris spicata ‘Kobold,’ and the deep lavender blossoms of Stokesia (more commonly called Stokes’ Aster).

Be aware that Asclepias tuberosa does not appreciate being moved once it’s settled in. The plants produce deep taproots that are better left alone once planted, so site it with care, let it be, and enjoy all of the benefits of this tremendously valuable plant.