How To Identify Deciduous Trees and Shrubs in Winter

Even after deciduous trees and shrubs shed their leaves, most can be easily identified using their winter characteristics. Buds, bark and overwintering fruits are reliable clues to identification. With a little practice, they're as useful as leaves to pin down a plant's name.

Look at Twigs

If they’re within easy reach, twigs have many features that are helpful for winter identification. The size, shape and arrangement of buds and leaf scars are reliable clues. Using green ash (Fraxinus pennsylvanica) as an example, here's what to look for. 

Depending on the species, buds may be covered with no scales, one scale, or several scales. Bud shape may be long and narrow, short and wide, or somewhere in between. Leaf scars and vascular bundle scars may be conspicuous or so small they are difficult to see without magnification. In any case, the combination of characteristics is unique for a species, as shown in the photographs below. 

Box Elder (Acer negundo) twigs are maroon in winter, often with a blue-gray, waxy coating. Surfaces with that coating are said be glaucous. The twigs turn green in spring but may still be glaucous.

Buds scales are covered with short gray hairs that are easiest to see with a magnifying lens. There are two buds per node, so Box Elder has opposite buds. If the twigs and buds are out of reach, look at the branching pattern. That, too, will be opposite.

Leaf scars are narrowly V-shaped. The opposing V’s meet on each side of the twig, forming a point.

Inside each leaf scar are three vascular bundle scars (arrows, left). One is directly below the bud and two are at the tips of the V, one on each side. 

The ends of Black Walnut (Juglans nigra) twigs are covered with short, gray or white hairs. Buds are similarly hairy, and they are longer than wide. Lateral buds are alternate – one per node.

Beneath each lateral bud is a heart-shaped or V-shaped leaf scar. Vascular bundle scars are dark brown. One semicircular bundle scar is at the bottom of the heart and two smaller bundle scars are at the top. The pattern reminds some of a face, with two eyes above and a mouth below.

The buds and leaf scars of butternut, Juglans cinerea, are similar, but the leaf scars are straight across the top instead of notched. 

Red Elderberry (Sambucus racemosa) doesn’t have twigs, but its coarse stems and branches are just as distinctive.

The lateral buds are opposite and covered with green, brown or red scales. Flower buds tend to be larger – almost as wide as they are long.

Below the buds are triangular or shield-shaped leaf scars with five large vascular bundle scars.

The stems and branches of Red Elderberry also have conspicuous “warts” on their bark. These raised areas are lenticels, eruptions of the bark that allow gas exchange with interior tissues. Many species have lenticels on their twigs or young stems, but few are as conspicuous as Red Elderberry. 

Look Closely at Bud Arrangement

Knowing the bud arrangement – opposite, subopposite, alternate or whorled – is especially helpful because it quickly narrows the choices for identification. If the twigs and buds are out of reach, look for the branching pattern. It will have the same arrangement as the buds. Be sure to look at several branches and twigs; there may be more than one kind of arrangement. Although that can be confusing, it’s useful information.

With the bud or branch arrangement determined, the next step is to find or recall a list of species that belong in that group. To remember species with an opposite arrangement, a helpful mnemonic is “MAD Cap Buck Horse.”

• M is for maples, genus Acer.
• A is for ashes, genus Fraxinus.
• D is for dogwoods, genus Cornus.
• Cap is for the family Caprifoliaceae, which includes honeysuckle shrubs, genera Lonicera and Diervilla.
• Buck and Horse are for Buckeyes and Horsechestnuts, respectively. Both are trees in the genus Aesculus. 

Other trees and shrubs also have an opposite arrangement. To the list above add Viburnums (Viburnum species), Elderberries (Sambucus species), burning bushes (Euonymus species) and buffaloberries (Shepherdia species).  Amur Corktree (Phellodendron amurense), an invasive tree, also has opposite buds and branches. There are several more genera in this group. A thorough guidebook will point them out.

If the plant doesn’t have opposite buds, then there are three other categories to choose from. Most of the remaining plants will have an alternate arrangement. Woody plants with a whorled arrangement are unusual. Catalpa (Catalpa speciosa), an introduced tree, has three buds and leaf scars per node. Native Bog Laurel (Kalmia polifolia), a low shrub of bogs, can have either an opposite or a whorled arrangement. Subopposite buds are unusual, too. Common Buckthorn (Rhamnus cathartica) has buds that can be subopposite, opposite or alternate.

Look at Bark

The bark of many trees and shrubs is distinctive enough to identify the species. The tricky thing is that bark changes with age. It often starts out smooth but develops more texture as the tree or shrub ages. Despite that change, the appearance of bark is a useful characteristic. The following questions highlight some of the features to look for.  

•  Is the mature bark ridged and furrowed? If so, how deep are the furrows? Do the ridges and furrows form any kind of pattern?
• Instead of ridges, does the mature bark have flat-topped plates, shaggy strips, or scales?
• Are lenticels present on younger bark? If so, are they round, linear, or both? If they are linear, what direction do they run?
• What color is the inner bark, the layer just below the surface? The brightly colored inner bark of some species provides a clue to their identification.

As with twigs, bark shows a lot of variety, both within and among species. The photographs below hint at some of that diversity.

Green Ash bark is brown to red when young, with white lenticels. Older bark is ridged and furrowed in a tight, honeycomb or diamond-shaped pattern.

The young stem on the far left is about 1 inch in diameter. The trunk of the mature tree is about 14 inches in diameter.

Young stems of Common Buckthorn (Rhamnus cathartica) have smooth, gray or brown bark with prominent, horizontal lenticels. Older bark is dark brown, rough and flaky. The photo at far left shows a clump of buckthorn stems at various ages. The largest one is about 3 inches in diameter.

One quick way to identify Common Buckthorn is by its bright orange inner bark. 

Black Cherry (Prunus serotina) has bark that changes drastically with age. On young trees, the bark is red-brown and smooth with horizontal white lenticels. The trunk at far left is about 4 inches in diameter.

In contrast, the bark of mature Black Cherry trees is scaly. Some say it looks like burned potato chips. The trunk at left is about 15 inches in diameter.

Look for Fruits

The fruits of most woody plants are shed before winter, but those of a few species tend to hang on. If they are present, their size, shape, color and texture (dry vs. juicy) and their placement on branches are important to note. As shown below, fruits can be easy and important characteristics for identification.

Bittersweet vines (Celastrus species) are easiest to identify by their persistent winter fruits. Invasive Oriental Bittersweet (C. orbiculatus), far left, has yellow capsules that open to expose fleshy orange arils. The clusters are found along the length of the stems.  In contrast, American Bittersweet (C. scandens), left, has orange capsules and red arils. Its clusters are found only at the ends of the stems.

Winged fruits are called samaras. Some samaras are in pairs, as in Amur Maple (Acer ginnala), far left. Other maples also have paired samaras.

Some samaras are single, as in Green Ash (Fraxinus pennsylvanica), left. Other ash species are similar. Some call the samaras keys, because a cluster of them resembles a bunch of keys on a ring.

Berries and berry-like fruits are typically juicy and either spherical or oblong.  Common Buckthorn (Rhamnus cathartica) has dark blue, almost black, berry-like fruits clustered at the nodes (far left). Inside each are 3-4 hard, seed-like stones (arrows, left). This type of fruit – juicy or fleshy with one or a few stones – is called a drupe. Berries are similar, but they lack stones and are juicy throughout.

Look for a Guidebook

Using a combination of buds, leaf scars, bark and fruits, anyone can identify trees, shrubs and woody vines in winter. All that’s needed is a guidebook, a reference that matches observed characteristics to names of species. Guides dedicated to winter identification are few, but there are some resources online and in bookstores that may be helpful.

• The LEAF Program from UW-Stevens Point is a K-12 forestry education initiative that offers many online resources. Under the link for Curriculum & Resources, choose LEAF Tree Identification Tools. The LEAF Winter Tree ID Key is available there as a downloadable PDF.
• Winter Botany: An identification guide to native trees and shrubs, by William Trelease. Dover, 1967. ISBN 0-486-21800-7.
• Fruit Key and Twig Key to Trees and Shrubs, by William M. Harlow. Dover, 1959. ISBN 0-486-20511-8.
• Winter Tree Finder: A Manual for Identifying Deciduous Trees in Winter, by May T. Watts and Tom Watts. Nature Study Guild Publishers, 1970.

Reviews of these references or suggestions for others are welcome. Please use the contact form at right to offer comments. Upcoming posts will feature winter identification of select groups of plants. 

Sunset for Kentucky Coffee Tree?

Its numbers are declining in nature. A look into its distant past could explain why.

 

A female Kentucky coffee tree, Gymnocladus dioicus, in November 2020.

Kentucky coffee tree (Gymnocladus dioicus) cuts a striking silhouette in the landscape. Its stout branches, plated bark, and chunky, persistent pods stand out, especially in winter. Nothing else looks like this.

And nothing else has quite its combination of puzzling traits. Its range today is strangely limited, its fruits should attract herbivores but don’t, and natural distribution of its seeds, heavy and nonbuoyant, is mostly by water. Ecologically, the tree doesn’t make sense. That wasn’t always so.

A Glimpse Into the Past

Kentucky coffee tree is thought to have arrived here sometime during the Miocene, an epoch of geologic time that extended from 23 million to 5 million years ago (Zaya & Howe, 2009, citing Tiffney & Manchester, 2001). Grasslands and savannas were widespread then, and so were many herbivores. In fact, North America then is thought to have resembled the African savanna today, at least in terms of the diversity of animals and the structure of their communities (MacFadden, 2000, citing Webb, 1997, 1983).  

Important to the story of Kentucky coffee tree, many of those herbivores were huge. They were the megafauna, and they included North American rhinos, camels and elephant-like animals called gomphotheres (MacFadden, 2000; Zaya & Howe, 2009, citing Webb, 1983, and Janis et al. 2004).  Long after the Miocene, land bridges brought additional large mammals to North America, including giant sloths and armadillos from South America and mammoths and bison from Eurasia (MacFadden, 2000).

The exact diets of the megafauna aren’t known, but it’s speculated that they included the large fruits of plants like Kentucky coffee tree. The big animals would have been tall enough to reach the tough pods and strong enough to open them, enticed, perhaps, by the sweet green pulp inside. The extremely hard seeds could have withstood their forceful bites and been passed through their digestive systems intact, arriving, finally, in a pile of dung, there to begin another generation (Zaya & Howe, 2009).

Hints of a Different Life

Kentucky coffee tree thus could have spread wherever its herbivores roamed. The tree itself hints that it was once more abundant and widely distributed. Although the natural range of the tree today is confined mostly to floodplain terraces (Smith, 2008, 2018), at one time it was likely more common in open, early successional (colonizing or re-colonizing) habitats. Evidence comes in part from its growth habits: It reproduces vegetatively, and vigorously, from root sprouts, its seedlings don’t tolerate shade, and the tree tolerates drought, a combination of traits that would suit it for life in disturbed uplands (Zaya & Howe, 2009, citing Huxley & Griffiths, 1992).

The flowers, too, hint that Kentucky coffee tree was once more abundant. Most trees produce either male (pollen producing) or female (fruit producing) flowers on separate plants. Separation ensures outcrossing and offers the potential benefits of genetic mixing – an advantage in changing environments – but it would have been a disadvantage if opposite individuals had been few and far between. That disadvantage could be overcome if the flowers were pollinated by specialists. Insects dedicated to Kentucky coffee tree would gather pollen only from those flowers, and they would travel some distance to do so. That isn’t the case with this tree, however. Its flowers are likely pollinated by generalists, insects that gather pollen from a variety of sources and are unlikely to go far (Zaya & Howe, 2009).

Range map from USDA PLANTS database, 

December 2020. 

Like the flowers, the seeds plant suspicions of a wider distribution. In its modern floodplain habitats, the seeds are spread primarily by water. That’s unexpected, judging from their heft. Water-borne seeds tend to be small, light and buoyant; those of Kentucky coffee tree are large and heavy and they sink quickly. By all appearances, they aren’t adapted for spread by water. They are adapted for spread by animals. Why would they be enclosed in a sweet, green goo – a lure and reward for herbivores – if they’re intended to be carried passively, and inanimately, by water?

Survival in a Changed World

Together these anomalies point to a vastly different life. Times have changed, drastically. The megafauna that could have helped the tree spread began declining 15,000 years ago, victims of climate and habitat change, disease, overhunting or some combination of causes (MacFadden, 2000; Barlow, 2001). By 10,000 years ago at the latest, most of them were gone, and as far as Kentucky coffee tree is concerned, nothing has replaced them. Its fruits are poisonous to cows, sheep and other modern herbivores (Rowe & Geyer, undated). Even the largest plant eaters don’t have the voluminous digestive systems of megafauna, so they lack the greater diversity and number of intestinal microbes that are thought to have metabolized the toxins (Zaya & Howe, 2009, citing several studies). The fruits now fall and rot, uneaten, or the seeds germinate under the parent tree. Either way, distribution is severely limited. Even if the seeds are transported in streams, they won’t germinate there (Zaya & Howe, 2009, citing van der Pijl, 1982, and Murray, 1986), and their waterlogged journey would continue to confine them to lowland habitats.

Changes in its environment have made Kentucky coffee tree a rare find in the wild, so it is designated a species of special concern in Minnesota (Smith, 2018). It’s in no danger of extinction, however. Humans have been spreading its seeds, intentionally and unintentionally, for centuries. Early Native Americans used various parts of the plant for medicine and food, including a coffee-like drink made from roasted seeds (VanNatta, 2009; NAEB, 2020). In fact, the presence of Kentucky coffee tree on floodplains today may reflect the movement of Native Americans along stream corridors in the past (VanNatta, 2009). European immigrants also used the seeds as a coffee substitute and, like Native Americans, utilized the seeds as game pieces (Zaya & Howe ,2009; VanNatta 2009).

Today the tree is most often planted as an ornamental or shade tree, as a “rewilded” tree returned to its probable upland haunts, or as a curious link to the past. No one is certain what, if anything, ate its fruits. If nothing did, the tree’s investment in pods, pulp and seeds had no payoff. That seems unlikely. Surely this unique tree fed something besides our imaginations.

References

Barlow, C. (2001). Ghost Stories from the Ice Age. Natural History, 110(7), 62.

MacFadden, B.J. (2000). Cenozoic mammalian herbivores from the Americas: Reconstructing ancient diets and terrestrial communities. Annual Review of Ecology and Systematics 31, 35-59.

Native American Ethnobotany (NAEB) Database. Accessed November 28, 2020. http://naeb.brit.org/uses/search/?string=Gymnocladus+dioicus

Row, J.M., and Geyer, W. (n.d.). Plant Guide: Kentucky Coffeetree. USDA NRCS Plants Database. https://plants.usda.gov/plantguide/pdf/cs_gydi.pdf.

Smith. W.R. (2008). Trees and Shrubs of Minnesota. University of Minnesota Press.

Smith. W. (2018). Rare Species Guide: Gymnocladus dioica. Minnesota Department of Natural Resources. https://bit.ly/3mE5Ea2

USDA, NRCS. 2020. The PLANTS Database (http://plants.usda.gov, 3 December 2020). National Plant Data Team, Greensboro, NC 27401-4901 USA.

VanNatta, A. (2009). Ecological importance of Native Americans Culture to the Kentucky Coffee Tree (Gymnocladus dioicus). University of Wisconsin Stevens Point. https://www.uwsp.edu/forestry/StuJournals/Documents/NA/avannatta.pdf

Zaya, D.N., and Howe, H.F. (2009). The anomalous Kentucky coffeetree: megafaunal fruit sinking to extinction? Oecologia, 161, 221-226. https://doi.org/10.1007/s00442-009-1372-3.

 

 

Status of Emerald Ash Borer in Minnesota

 

Range of confirmed emerald ash borer in Minnesota. Source: Minnesota Department of Agriculture.

Emerald ash borer, or EAB, has been confirmed in 25 counties in Minnesota. The latest discoveries were in late summer 2020 in Carver and Sibley Counties, southwest of the Twin Cities. All affected counties are shown in the map above, which is a snapshot of an interactive map maintained by the Minnesota Department of Agriculture. It shows quarantined counties in pink, the quarantine boundary in red, and the boundaries of generally infested areas in green. Click on the map or the link in this paragraph to view the interactive version.

Movement of some types of wood out of the quarantine area is regulated. Ash logs and lumber, ash tree waste, ash chips and mulch, and any hardwood (deciduous) firewood should not be moved outside the quarantine area without a Compliance Agreement with the MDA. The agreement requires that the wood be treated in any of several ways to minimize the risk of EAB spread. To get an agreement, call Arrest the Pest at 888-545-6684 or email arrest.the.pest@state.mn.us.

How to Detect EAB

EAB is a serious pest of all native ash trees. The insect, Agrilus planipennis, overwinters as larveae or pupae in the bark or wood. Metallic, green adults, just shorter than the width of a penny, emerge from the trees in spring or early summer and later lay their eggs on ash trees. The larvae burrow into the bark and feed on the inner bark and outer sapwood, tissues that conduct water, nutrients and sugars throughout the tree. Infested trees die 1-3 years later.

During the growing season, one symptom of EAB infestation is die-back of the canopy, starting at the crown and moving down. Some trees also develop epicormic sprouts, branches that grow from the lower part of the trunk. In fall and winter, look for woodpecker holes (the birds eat EAB larvae), cracks in the bark and, under the bark, S-shaped galleries of EAB larvae.

From left: 1) Canopy dieback; Source: Steven Katovich, Bugwood.org. 2) Epicormic sprouts; Source: Pennsylvania Department of Conservation and Natural Resources - Forestry, Bugwood.org. 3) Woodpecker damage; Source: Kenneth R. Law, USDA APHIS PPQ, Bugwood.org. 4) EAB galleries: Source: Kelly Oten, North Carolina Forest Service, Bugwood.org. Full photo credits are below.

To determine if an ash tree might be infested with EAB, use the MDA’s “Does My Tree Have Emerald Ash Borer (EAB)?”  If you then suspect an EAB infestation, call Arrest the Pest at 1-888-545-6684 or email arrest.the.pest@state.mn.us.

Help Find EAB

Emerald ashborer. Source:Leah Bauer, 

USDA Forest Service Northern Research 

Station, Bugwood.org.

Emerald ash borer beetles are inconspicuous, but a University of Minnesota citizen science project used a unique tool to find them: Wasps. Volunteers for the project, called Wasp Watchers, monitored nests of the smoky winged beetle bandit wasp, Cerceris fumipennis, for their beetle prey. Finding EAB alerted scientists to locations of affected ash trees, sometimes before the trees began showing symptoms.

The Wasp Watchers program ended in July 2020, but volunteers can still monitor wasp colonies for beetle prey and report their findings through iNaturalist. Wasps or nesting sites with EAB should also be reported to Arrest the Pest. These web pages offer more information:

•          Sunsetting Wasp Watchers
•          Wasp Watchers Training Material

What About Other States?

For information about EAB in neighboring states, visit these websites:

•       North Dakota
•         South Dakota
•          Iowa
•          Wisconsin

References and More Information

Haack, R. A., et al. Emerald Ash Borer Biology and Invasion History. Chapter 1 in Biology and Control of Emerald Ash Borer. USDA, March 2015. https://www.fs.fed.us/foresthealth/technology/pdfs/FHTET-2014-09_Biology_Control_EAB.pdf

Emerald Ash Borer Program. Minnesota Department of Agriculture. Website accessed October 29, 2020.

Questions & Answers About the EAB Quarantine & Compliance Agreements. Minnesota Department of Agriculture. Website accessed October 29, 2020.

Photo Credits

Canopy dieback by Steven Katovich, Bugwood.org, licensed under a Creative Commons Attribution 3.0 license.

Epicormic sprouts by Pennsylvania Department of Conservation and Natural Resources – Forestry, Bugwood.org, licensed under a Creative Commons Attribution 3.0 License.

Woodpecker damage by Kenneth R. Law, USDA APHIS PPQ, Bugwood.org, licensed under a Creative Commons Attribution 3.0 License.

EAB galleries by Kelly Oten, North Carolina Forest Service, Bugwood.org, licensed under a Creative Commons Attribution-Noncommercial 3.0 License.

Emerald ash borer by Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org, licensed under a Creative Commons Attribution-Noncommercial 3.0 License.

Elm Trees Still in Dutch

Beautiful but foreboding, the galleries of the European elm bark beetle spell trouble for this American elm. They also cut to the heart of a cautionary tale.

Some months ago, a female beetle found or was lured to this weakened tree to build a nursery. She burrowed through the bark to the outermost layer of wood, where she chewed a tunnel parallel with the grain. She laid eggs along the sides of her gallery, and when they hatched the larvae then tunneled away from her path. After metamorphosis, a phalanx of new adults exited the tree and flew to other elms to feed.

By themselves, the European beetles, Scolytus multistriatus, aren’t a disaster for elms. Neither are native elm bark beetles, Hylurgopinus rufipes, which have similar habits. The much greater harm comes from the fungi they can carry from diseased elms, as this one was, to healthy elms. The fungi, Ophiostoma ulmi and its more aggressive cousin, Ophiostoma novo-ulmi, are better known as the agents of Dutch elm disease.

This is a disease of deprivation. The spores carried into the tree by the beetles germinate inside the xylem, the water-conducting vessels of the wood. As the fungus grows and reproduces, it causes living cells in the wood to push balloon-like extensions called tyloses into the vessels. Potentially, the tyloses could inhibit the spread of the fungus, but they usually form too late. Instead of defending the tree, they combine with gums produced by the tree’s degraded cell walls and the fungal masses themselves to plug the vessels and block the flow of water to the leaves. The leaves then wilt, turn yellow and then brown, and eventually fall. This symptom, called flagging, is one of the first visible signs of trouble.

Just as elms respond too slowly to defend themselves, so communities responded too slowly to stop the spread of this disease. Introduced into the U.S. in the 1920s on imported elm wood, the fungus spread quickly across the country. In Minnesota, the first diseased trees were discovered in the early 1960s in St. Paul and Monticello. Aided by urban monocultures and initial doubt that the European beetles would survive here, Dutch elm disease soon spread to every county in the state. All three native elms - American elms (Ulmus americana), rock elms (U. thomasii) and red elms (U. rubra) – are susceptible, and thousands have succumbed.

The good news is that elms persist. Young elms that survived the first onslaught of the disease have matured, and it’s worth the effort to protect them. In addition, resistant – but not immune – elms have been selected from surviving American elms or hybrid American and Asiatic elms, and they are being planted in greater numbers. They, too, would benefit from sanitation practices that take the fungus out of circulation.

Among its many lessons, Dutch elm disease teaches the importance of tackling invasive species (ones that are introduced and harmful) before they cause widespread damage. Awareness is an important first step to doing that. The page about invasive species includes links to many resources that can help identify and manage such species while their numbers are low. It can be a wily game, but as anyone who’s lost an elm might say, it’s one worth playing well.

 

 References and further reading

History of Dutch Elm Disease in Minnesota, by David W. French. University of Minnesota Extension Service.

Dutch Elm Disease. Minnesota Department of Agriculture. Website accessed October 13, 2020.

Dutch elm disease. University of Minnesota Extension.

D’Arcy, C.J. 2000. Dutch elm disease. The Plant Health Instructor. DOI: 10.1094/PHI-I-2000-0721-02
Updated 2005. Available on the website of the American Phytopathological Society, https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/DutchElm.aspx.

Plant Profile: New England Aster

New England Aster (Symphyotrichum novae-angliae) is a widespread native plant of open, low grasslands, meadows, roadsides and shore lands. Its stout, hairy stems grow 3-6 feet tall and branch at the top. Alternate, hairy leaves are up to 4 inches long and 1 inch wide. They clasp the stem at their bases. 

Pink to purple flowers bloom from August into October at the ends of the stems. At 3/4 to 1-1/2 inches wide, the flowers are among the largest and showiest of the asters, and they can trick the eye. What looks like one flower is actually a group of florets in a head, called a head inflorescence. The center of the head bears small, tubular, yellow to orange disk florets. Around the disk are 50 or more pink or purple ray florets, so called because each bears a single, petal-like ray. 

Below the head are green or greenish-purple bracts called phyllaries. The phyllaries of New England aster are narrow or lance-shaped with long points. They curve away from the head and are covered with short hairs. Some of the hairs are tipped with bulbous glands, appearing as tiny glistening dots under a magnifying lens. The stalk of each inflorescence, called a peduncle, is also hairy. 

If you find New England Aster in bloom -- and if you have a steady hand and lots of patience -- pinch off a few disk flowers and use a needle to slit them open lengthwise. A 20x or higher magnifying lens will help. Inside the flower you may see that the filaments supporting the anthers are fused into a column that surrounds the style, the neck of the pistil. When the anthers open, they drop their pollen into the column. As the style elongates, its hairy surface picks up the pollen and makes it available to pollinators. The fused filaments of the stamens could explain the genus name Symphyotrichum, which means "joined hairs."

Many other asters in this region bloom at about the same time as New England Aster, but this species blooms later than most. Also, no other native aster has the same combination of large flower heads, clasping leaves, and hairy stems, leaves and phyllaries.

New England Aster is a late-season source of pollen and nectar for bees, moths and butterflies. To grow it in a garden or landscape, choose a location with moist to mesic, rich soil and full sun to partial shade. The plant will spread by rhizomes to form clumps. To maintain the plant's vigor in a garden, divide it in spring every three years. 

References:

USDA Plants Database, https://plants.usda.gov/core/profile?symbol=SYNO2

Wetland Plants of Minnesota, by Steve W. Chadde. A Bogman Guide, 2012. 

Pollinators of Native Plants, by Heather Holm. Pollination Press, LLC, 2014.