White Snakeroot, and a Bit of a Paradox

White Snakeroot (Ageratina altissima) provides food for late summer and fall visitors, primarily small critters.  Its button-like clusters of tiny tubular flowers offer nectar to a variety of potential pollinators, and flower buds and leaves provide food for other insect diners.

White Snakeroot (Ageratina altissima)

In my shade garden in central New Jersey, Bumble Bees and Small Carpenter Bees (Ceratina species) drink happily from the flowers.

White Snakeroot (Ageratina altissima) with Small Carpenter Bee (Ceratina species)

On a late September Sunday at Garden in the Woods in Framingham, Massachusetts, I watched while Bumble Bees and Honey Bees took advantage of White Snakeroot’s abundant nectar.

White Snakeroot (Ageratina altissima) with Bumble Bee (Bombus species)

White Snakeroot (Ageratina altissima) with Honey Bee (Apis mellifera)

In a sunny woods-edge location at Bowman’s Hill Wildflower Preserve near New Hope, Pennsylvania, several butterfly species found needed nourishment in the nectar  White Snakeroot flowers offered.

Painted Ladies and Sachem helped themselves to White Snakeroot’s sustaining beverage. These butterflies have been around much of the summer and fall, drinking from the flowers in bloom, moving from one species to the next as the season changed.

Painted Lady butterfly drinking nectar from White Snakeroot (Ageratina altissima)

Sachem drinking nectar from White Snakeroot (Ageratina altissima)

I was excited to see a Fiery Skipper, a butterfly that is rare in Pennsylvania, but a common resident in the southern United States. Fiery Skippers are among the butterfly species that regularly attempt to push the envelope of their range by emigrating to the north. White Snakeroot’s refreshing nectar rewarded this individual for its exploration efforts.

Fiery Skipper drinking nectar from White Snakeroot (Ageratina altissima)

Meanwhile, a Monarch fueled up for a flight in the opposite direction, heading south towards its winter territory in Mexico.

Monarch drinking nectar from White Snakeroot (Ageratina altissima)

If these potential pollinators do the job for which White Snakeroot has enticed them to visit its flowers, pollination occurs, and a type of fruit, called an achene, develops. The achene looks like a seed with a tiny hair-like parasol attached, designed to be dispersed by the wind to a favorable place for another White Snakeroot plant to germinate and grow.

White Snakeroot (Ageratina altissima), ready to disperse its fruit

At Bowman’s Hill Wildflower Preserve, an insect that looked a bit like a stink bug turned out to be the opposite – Harmostes fraterulus, one of the scentless plant bugs. Pennsylvania is thought to be the northern edge of Harmostes fraterulus’s range. Scentless plant bugs are a group of true bugs that lack glands to produce an unpleasant smell, quite unlike stink bugs who are named for their ability to do this. Harmostes fraterulus feeds on the flowers of several Aster (Asteraceae) family members, of which White Snakeroot is one.

Harmostes fraterulus on White Snakeroot (Ageratina altissima)

It’s interesting that this small insect is able to eat parts of White Snakeroot, since this plant contains potent toxins evolved to prevent herbivores from consuming it. These toxins are so effective that they can be fatal to mammals.  As you might guess, deer do not eat this plant.  If cows graze on a sufficient amount of White Snakeroot, the milk they produce is toxic to humans.  In the nineteenth century, many people became sick or even died as a result of drinking this tainted milk, most famously, Abraham Lincoln’s mother.

While this plant’s chemical defenses are potent enough to sicken or even kill large mammals, some tiny insects have successfully adapted to use this plant as their food source (host plant). A type of small fly species, a midge named Schizomyia eupatoriflorae, specializes on White Snakeroot buds.  The larvae of this midge live inside the plant tissue, prompting the plant to produce a rounded gall that the developing midge uses for both food and shelter until it is ready to emerge as an adult.

White Snakeroot (Ageratina altissima) with galls caused by the plant’s reaction to being used by a midge, Schizomyia eupatoriflorae

Flowers often have a lower concentration of a plant’s chemical defenses than do the other plant parts such as leaves and stems. But there are even insects who have evolved to specialize on White Snakeroot’s leaves.  The one of which I most often see evidence is a leaf miner, Liriomyza eupatoriella, a type of fly. The larvae of Liriomyza eupatoriella develop between the outer layers of the leaf, feeding on the tissues inside.

White Snakeroot (Ageratina altissima) with leaf mines caused by a leaf mining fly, Liriomyza eupatoriella

Mammals have plenty of other food alternatives (at least for now) without having to evolve a tolerance for White Snakeroot’s toxins. But tiny insects may gain an advantage if they can specialize on food that few others can consume (and live to tell the tale!), especially a relatively common food source like White Snakeroot.

Despite its toxicity, several Native American tribes found medicinal uses for White Snakeroot, often using the root, but other plant parts as well. Some sources say that a poultice to treat snakebites was made from the root, resulting in the common name, White Snakeroot.

White Snakeroot is a plant of woods and woods edges. It prefers light shade but can tolerate partial sun, with moist to slightly dry soils.  In Canada it is native in Ontario and Quebec provinces and the Northwest Territories, and in the United States from Maine to eastern North Dakota, south to Texas and the Florida panhandle, although it is much less widespread in the southeastern U.S.

American Goldfinch, taking refuge on White Snakeroot (Ageratina altissima)



Brock, Jim P.; Kauffman, Ken. Kaufman Field Guide to Butterflies of North America.  2003.

Cech, Rick; Tudor, Guy. Butterflies of the East Coast.  2005.

Coffey, Timothy. The History and Folklore of North American Wildflowers.  1993.

Eaton, Eric R.; Kauffman, Ken. Kaufman Field Guide to Insects of North America.  2007.

Eiseman, Charley; Charney, Noah. Tracks & Sign of Insects and Other Invertebrates. 2010.

Foster, Steven; Duke, James A. A Field Guide to Medicinal Plants and Herbs of Eastern and Central North America.  2000.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania.  2007

Illinois Wildflowers

USDA NRCS Plant Database

Harmostes fraterulus:

Maryland Biodiversity Project

Wheeler, A. G. Jr.; Miller, Gary L. Harmostes Fraterculus (HEMIPTERA: RHOPALIDAE): Field History, Laboratory Rearing, and Descriptions of Immature Stages. 1983.

Wheeler, A. G. Jr.  Harmostes reflexulus (Say) (Hemiptera: Rhopalidae): New Western U.S. Host Records, Analysis of Host-Plant Range, and Notes on Seasonality.  2013.





Partridge Pea Puzzles

Bright yellow Partridge Pea (Chamaecrista fasciculata) flowers peek out from between the stems of taller grasses and flowering forbs in meadows, prairies, stream banks and other open areas from July through early September.

Partridge Pea (Chamaecrista fasciculata)

Partridge Pea’s flowers are tucked in the leaf axils down the length of the stem.

Partridge Pea (Chamaecrista fasciculata)

Each flower has five yellow petals, with one much longer than the other four, and another partially curled toward the center of the flower, where its reproductive parts are located. A 1992 study showed that the curved petal directs floral visitors to the flower’s reproductive parts, first to the pistil (female reproductive part), and then the stamens (male reproductive parts).[1]  The red smudges on the petals are part of the visual allure to pollinators.

Partridge Pea (Chamaecrista fasciculata)

In the Partridge Pea flower in the photo above you can see the three evenly sized petals at the top, one petal in the lower left that curls toward the center of the flower, and an over-sized petal at the lower right. The stamens are mostly clustered at the middle of the flower.  The pistil resembles a hook projecting from beneath the right-most stamen. It is visible at the top of the over-sized petal.  Imagine a pollinator coming in for a landing using the over-sized petal as a runway, guided by the curved petal, with the red smudges on the petals as beacons. The pollinator brushes first against the receptive stigma at the tip of the pistil, depositing pollen from the last flower visited, then moves on to harvest pollen from the stamens.

Bumble Bee harvesting pollen from Partridge Pea (Chamaecrista fasciculata) flower. Bumble Bees are adept at buzz pollination.

Partridge Pea flowers offer pollen as a reward to their visitors, but they don’t produce nectar. As a result, bees that collect pollen are the most likely visitors of the flowers.  But the bees have to have skills in order to harvest Partridge Pea’s pollen, since it requires special handling in order to access it.  The pollen is dispersed through a slit at the tip of the stamen’s anther.  Pollen can be shaken out of the anther as a result of buzz pollination, a technique in which a bee clings to the flower while vibrating its wing muscles without actually moving its wings.  ‘Milking’ the anther with a series of strokes is another method of successfully harvesting Partridge Pea’s pollen.[2]

Honey Bee harvesting pollen from Partridge Pea (Chamaecrista fasciculata) flower. Honey Bees can’t perform buzz pollination, so may be using the ‘milking’ technique.

Eastern Carpenter Bee harvesting pollen from Partridge Pea (Chamaecrista fasciculata) flower.

Butterflies aren’t interested in Partridge Pea flowers, since they don’t offer nectar. But several butterfly species use Partridge Pea as a food plant for their caterpillars, including the Sleepy Orange and Cloudless Sulphur.

Sleepy Orange drinking nectar from Winged Loosestrife (Lythrum alatum)

Cloudless Sulphur

Gray Hairstreak and caterpillar on Partridge Pea (Chamaecrista fasciculata). Can you see the tiny caterpillar clinging to a leaf in the lower left of the photo?

When I saw a Gray Hairstreak butterfly spending time walking around a Partridge Pea plant, it seemed possible that this was a female laying eggs. Gray Hairstreaks use some Pea family members as caterpillar food, including clovers and tick-trefoils, although I haven’t seen any confirmation that they would use Partridge Pea.

Gray Hairstreak on Partridge Pea (Chamaecrista fasciculata).

A closer look showed that the butterfly was visiting Partridge Pea for nectar after all, but it was nectar that is made available through extrafloral nectaries on the base of the stem of each leaf.  This was a great benefit for the butterfly, but not much help for the plant, since the butterfly offered no services in return.

Gray Hairstreak drinking nectar from an extrafloral nectary on Partridge Pea (Chamaecrista fasciculata)

When present, extrafloral nectaries are generally a plant’s adaptation to entice insects that are predators of herbivores to visit and protect the plant. Ants are especially important in this role, since caterpillars are a very desirable food for them.  Some wasps and lady beetles are also potential protectors of plants.  While they are interested in nectar for themselves, they are also on the hunt for insects to feed to their larvae.  The wasps and lady beetles may rid the plant of the caterpillars or other insects who would eat it.  Nectar is provided in exchange for this protection.

Partridge Pea’s extrafloral nectaries look like tiny open pots, glistening with nectar, an open invitation to thirsty insects cruising through, not all of whom will offer services to the plant.

The two round pot-like appendages near the base of the Partridge Pea (Chamaecrista fasciculata) leaf stems are the extrafloral nectaries. Notice the glistening drops of nectar oozing from them.

While I have seen ants working Partridge Pea extrafloral nectaries, I was surprised at the variety of insects I saw drinking from them at one location I visited. It makes me wonder whether the cost of providing this nectar is worth the protection gained from them.  In addition to the Gray Hairstreak, I watched while a Bumble Bee spent more time visiting the extrafloral nectaries than the flowers.

Bumble Bee drinking nectar from a Partridge Pea (Chamaecrista fasciculata) extrafloral nectary.

After visiting several extrafloral nectaries, the Bumble Bee moved on to a flower.

I saw several Paper Wasps visit the nectaries. Since these wasps hunt caterpillars to feed their larvae, they do have the potential to provide a service in exchange for a tasty drink.

Paper Wasp (Polistes species) drinking from an extrafloral nectary on Partridge Pea (Chamaecrista fasciculata)

Paper Wasp (Polistes species) drinking from an extrafloral nectary on Partridge Pea (Chamaecrista fasciculata)

‘That was tasty!’ Paper Wasp (Polistes species) on Partridge Pea (Chamaecrista fasciculata)

Some accounts of Partridge Pea say that the leaves will sometimes fold up when they are touched. I’ve tried it several times, but I have never had Partridge Pea respond to my touch.  However, I have seen Partridge Pea plants with their leaves folded, so I’m guessing the plant folds its leaves in response to some stimuli, but I haven’t found an explanation for what it might be.  Maybe it’s a mechanism to prevent excessive water loss on hot, dry, or windy days.  Or maybe the plant responds to the touch of a butterfly laying eggs, and wants to minimize the leaf surface available to her.  I wish I knew!

Partridge Pea (Chamaecrista fasciculata) with leaflets folded. What prompted this?

If the name didn’t give away its family heritage, the fruits identify Partridge Pea as a member of the Pea or Bean (Fabaceae) family.  These fruits are an important winter source of food for birds, especially Bobwhites and Greater Prairie Chicken.

Partridge Pea (Chamaecrista fasciculata) with fruits typical of the Pea (Fabaceae) family.

Partridge Pea is an annual, but reseeds itself readily.  It likes sun, and can tolerate poor, dry soils.  It helps to fertilize soils through its release of nitrogen, and is sometimes used in stream bank stabilization.  Partridge Pea is native from Rhode Island to Minnesota in the north, south as far as southeastern New Mexico, and from Texas to Florida.

Partridge Pea (Chamaecrista fasciculate)

Related Posts

Will Work for Food – Extrafloral Nectaries

Cloudless Sulphurs Are on the Move

Sleepy Orange Butterflies are Back


Cech, Rick; Tudor, Guy. Butterflies of the East Coast.  2005.

Eaton, Eric R.; Kauffman, Ken. Kaufman Field Guide to Insects of North America.  2007.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania.  2007

Illinois Wildflowers

USDA NRCS Plant Database

USDA NRCS Plant Guide – Partridge Pea

[1], [2] Pollination and the Function of Floral Parts in Chamaecrista fasiculata, Andrea D. Wolfe and James R. Estes, 1992.

Natural Selection on Extrafloral Nectar Production in Chamaecrista Fasciculata: The Costs and Benefits of a Mutualism Trait


Rewards of a Butterfly Count

Common Buckeye

Why participate in a butterfly count? Well for one thing, you’ll be contributing to a citizen science project that gathers data to help assess how well butterfly species are doing over time.  Are numbers for each species in a given area declining, increasing, staying the same?  Are new species appearing in a location, are any disappearing?

Citizen science is my excuse, but it’s not my reason. I do it because it’s fun.

In mid-July, I participated in a count at Silver Lake Nature Center in Bristol, Pennsylvania. There were six of us.  We started looking for butterflies even before we entered the natural areas, searching carefully while walking across a lawn.  We were rewarded with sightings of Sachem, Peck’s Skippers, Eastern-tailed Blues, Common Buckeyes, Wild-Indigo Duskywings and Horace’s Duskywings.

Wild Indigo Duskywing on White Clover

Horace's Duskywing on White Clover

Horace’s Duskywing on White Clover

Eastern-tailed Blue

Are you wondering what attracted butterflies to the lawn, and why we even thought to look for them there?

It’s not every lawn that would be so productive. We were able to find butterflies in this lawn because it isn’t treated with pesticides or herbicides.  Most of the butterflies we saw were basking on blades of grass or drinking nectar from White Clover (Trifolium repens), a Pea (Fabaceae) family member.  If herbicides were used, the clover wouldn’t be there to feed butterflies, bees and other pollinators.  No crab grass would be available for Sachem and some other butterfly species to use as food for their caterpillars.  Pesticides would kill the butterflies directly.  Another bonus from having White Clover in the lawn is that it acts as a natural fertilizer, releasing nitrogen into the soil in a manner and quantity that can be used effectively by the other plants living there. It actually helps the grass to be healthier.  Even better, there is no excess chemical fertilizer to run off into streams, rivers and other waterways.  Years ago, white clover was included in grass seed mixes for this very purpose, until fashions changed, calling for a monoculture lawn with no clover, dandelions or violets.  Maintaining this uniform green carpet requires regular applications of herbicides to kill everything but grass, and synthetic fertilizer, to keep the grass growing.  The result is an expensive and toxic lawn maintenance regimen, devoid of butterflies, but welcoming to Japanese Beetles. As the fashion trend turns back, lawns become a safer, less toxic place to play for pets, children and even adults.

We worked our way across the lawn to the powerline cut through Delhass Woods. A male Widow Skimmer dragonfly stood guard in the grasses as we approached the entrance.

Male Widow Skimmer dragonfly

This is a much ricer habitat for butterflies, a sunny area filled with diverse plants that provide food for butterflies in the form of nectar, and food for their caterpillars in the form of the leaves of plants on which they specialize.  Plants in the Pea family, including Red Clover (Trifolium pretense), Crown Vetch (Securigera varia), and Wild indigo (Baptisia tinctoria), were a big draw for butterflies.

Wild indigo (Baptisia tinctoria)

Not only do the flowers offer nectar, but Wild Indigo Duskywings, Wood Nymphs, Clouded Sulphurs, Orange Sulphurs and other butterflies use these plants as food for their caterpillars.  All of these species were present in good numbers, along with Common Buckeyes, Peck’s Skippers, and Sachem.

Common Buckeye with Crown Vetch

Common Buckeye with Crown Vetch

Sachem on grape leaf

Pecks Skipper on Red Clover

Clouded Sulphur on Crown Vetch

We saw Wood Nymphs and Spicebush Swallowtails, but they didn’t pose for me this year. Last year they were pre-occupied enough with other activities to be more cooperative.

Spicebush Swallowtail drinking nectar from Turks-cap Lily

Wood Nymphs, mating

Surrounded by such a varied and rich habitat, an open area with woods on either side and a pond nearby, we couldn’t help but occasionally be distracted by birds and other critters, and some plants I don’t often see.

Maryland Meadow Beauty (Rhexia mariana)

Golden Hedge Hyssop (Gratiola aurea)

A Halloween Pennant dragonfly monitored our progress as we finished up our search of the powerline cut.

Female Halloween Pennant dragonfly

After a break, we moved on to the woods, marshes, and gardens. Cabbage Whites were everywhere.  Cabbage Whites aren’t native to North America, and can be a problem for farmers.  Their caterpillars feed on some plants in the mustard or cabbage (Brassicaceae) family. If you have ever found a small green caterpillar in your broccoli or kale (I have), it was probably a Cabbage White.  They have done so well in North America that they are often the species with the highest numbers for a count, as they were this day.  They ignored us while they mated in the woods.

Cabbages Whites mating

Eastern Tiger Swallowtails, Silver-spotter Skippers, Red Admirals and Sachem all enjoyed the nectar Buttonbush (Cephalanthus occidentalis) provided in the marshy areas.  Sachem also enjoyed the garden.

Eastern Tiger Swallowtail on Buttonbush (Cephalanthus occidentalis)


A week later I did another butterfly count at Bowman’s Hill Wildflower Preserve near New Hope, Pennsylvania. We had our best year since 2013, seeing twice as many butterflies as we did in 2014-2016.

Eastern Tiger Swallowtail on Joe-pye-weed (Eutrochium purpureum)

Some highlights were Juniper Hairstreaks, a small but beautiful butterfly that is considered ‘locally common’ because it is usually only found near its caterpillar food plant, Eastern Red Cedar (Juniperus virginiana).

Juniper Hairstreak on Short-toothed Mountain Mint (Pycnanthemum muticum)

We saw our highest number of Monarchs in the 6 years we have participated in the count.

Monarch butterfly resting on Yarrow

It was really exciting for me to see so many Sleepy Oranges, a southern species that returned to this Pennsylvania location after a nearly four-year absence.

Sleepy Orange drinking nectar from False Sunflower (Heliopsis helianthoides)

So why do a butterfly count? You’ll get to see beautiful butterflies and other critters interacting with gorgeous plants, and you’ll share the day with people who are enjoying themselves as much as you are, all while contributing to a citizen science effort that monitors the health of butterflies.  And you’ll have fun.

Gray Hairstreak on Grass-leaved Goldenrod (Euthamia graminifolia)

To find a butterfly count near you, check with the North American Butterfly Association.

Related Posts

What Do Juniper Hairstreaks and Cedar Waxwings Have in Common?

Sleepy Orange Butterflies are Back

Sleepy Orange Butterflies Overwintering in Pennsylvania

Combating Japanese Beetles

Butterflies Eat Their Peas



Butterflies Eat Their Peas

Silver-spotted Skippers are wide-ranging butterflies that are active from May through early fall. When their wings are folded or when they’re in flight, a large silvery patch on their otherwise mostly brown wings makes them easy to identify.  The butterfly is named for this marking.

Silver-spotted Skipper

Silver-spotted Skippers open the upper (dorsal) side of their wings to the sun when they are basking, revealing markings that resemble a stained-glass window.

Silver-spotted Skipper, basking in the sun.

I have to wonder if the silvery wing spot is an adaptation to make this butterfly resemble bird droppings. Insects, even butterflies, can be an important source of food for birds and some predatory insects.  This disguise would likely give Silver-spotted Skippers some protection from these predators, since bird droppings don’t attract them.

Silver-spotted Skipper, eating minerals from bird droppings. Does that silver splotch on the wings seem like a good disguise?

Silver-spotted Skippers can be seen drinking nectar from a variety of blossoms in meadows, along roadsides, marsh edges, and open woodlands, any place where they can also find the food their caterpillars require.

Silver-spotted Skipper drinking nectar from Indian Hemp (Apocynum cannabinum)

Silver-spotted Skipper drinking nectar from Common Milkweed (Asclepias syriaca)

So what’s the connection to peas?  While Silver-spotted Skipper butterflies drink nectar from many different plants, it’s their caterpillars that ‘eat their peas’. Silver-spotted Skipper caterpillars specialize on certain members of the Pea (Fabaceae) family, including Black Locust (Robinia pseudoacacia) trees, and several herbaceous (not woody) plants  called Tick-trefoils (Desmodium species).  The caterpillars typically munch on the foliage, flowers or buds of these plants, but they do it in such a discreet way that you would only notice if you were looking for it.

The Tick-trefoils all have three-parted leaves, and a tall-stemmed flower cluster. The pollinated flowers produce a chain of fruits that break apart when they’re ripe.  Fruits disperse as hitchhikers on passing animals, including humans.  I’ve often warn them home after a walk in the woods. This dispersal habit is the reason for the ‘tick’ part of the common name of these plants, since the fruits cling to an animal’s fur or clothing like a tick might.

Naked-flowered Tick-Trefoil (Desmodium nudiflorum) flowers and fruit

Naked-flowered Tick-Trefoil (Desmodium nudiflorum) flowers and fruit

Naked-flowered Tick-Trefoil (Desmodium nudiflorum) foliage

Naked-flowered Tick-Trefoil (Desmodium nudiflorum) foliage

Some of the food plants on which the Silver-spotted Skipper caterpillars depend are especially garden-worthy. Blue False Indigo (Baptisia australis), also called Blue Wild Indigo, and other plants of this genus are potential food plants for Silver-spotted Skipper caterpillars.  Its vivid purplish-blue flowers are primarily pollinated by Bumble Bees, but they are visited by other insects as well.  Blue False Indigo can grow to a maximum height of about 4 to 5 feet (1.25 to 1.5 meters), likes full sun to part shade, and can tolerate dry and clay soils.

Blue False Indigo (Baptisia australis) with likely pollinator

Blue False Indigo (Baptisia australis) with Silver-spotted Skipper

American Wisteria (Wisteria frutescens) is another favorite of Silver-spotted Skippers.  It is a deciduous vine with long hanging clusters of violet flowers in early summer, great for use on an arbor or fence.  If its flowers are pollinated, they are replaced by long pea pods later in the season.

American Wisteria (Wisteria frutescens)

American Wisteria (Wisteria frutescens) fruit

Female Silver-spotted Skippers lay eggs on the leaves of their caterpillar food plants. The caterpillars hatch from the eggs, spinning silk to pull the leaves of their host plants together to create a shelter.

Silver-spotted Skipper caterpillar in a shelter it created using its own silk and American Wisteria (Wisteria frutescens) leaves

Silver-spotted Skippers are not alone in their dependence on Pea family members. Gray Hairstreaks and Eastern-tailed Blues are among the other butterflies whose caterpillars ‘eat their peas’, using some of these same plants.

Female Gray Hairstreak butterfly preparing to lay an egg on flower buds of a Tick-trefoil

Eastern-Tailed Blue butterflies mating


Brock, Jim P.; Kauffman, Ken. Kaufman Field Guide to Butterflies of North America.  2003.

Cech, Rick; Tudor, Guy. Butterflies of the East Coast.  2005.

Glassberg, Jeffrey. Butterflies through Binoculars A Field Guide to Butterflies in the Boston-New York-Washington Region.  1993.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania.  2007

Spira, Timothy A. Wildflowers & Plant Communities of the Southern Appalachian Mountains & Piedmont.  2011.

Stearn, William T. Stearn’s Dictionary of Plant Names.  1996

Illinois Wildflowers

Missouri Botanical Garden





Blackberries, Butterflies, Bees and Birds

Common, or Allegheny, Blackberry (Rubus allegheniensis) brambles are blooming in woodlands and meadows throughout the local areas I frequent in central New Jersey and eastern Pennsylvania.  This Rose (Rosaceae) family member can be found from Quebec to Ontario provinces in Canada, south as far as South Carolina and Oklahoma in the United States.  It is also present in California and British Columbia.

Common, or Allegheny, Blackberry (Rubus allegheniensis)

At Bowman’s Hill Wildflower Preserve, near New Hope, Pennsylvania, I found masses of Wild Blackberry blooming in the meadow. Traditionally, the entire meadow is mowed during the winter, but this year a new method of meadow maintenance was introduced, one recommended by the Xerces Society.  Only part of the site was mowed last year, in order to preserve habitat for overwintering insects, birds, and other animals.  This new technique is already paying off, with an impressive display of flowering Blackberry canes, and an equally impressive variety of native pollinators visiting the flowers.

I wasn’t the only one to discover the Blackberries in bloom. From a distance, I could see that at least three Monarch butterflies were already there, flirting and drinking nectar, drawing me in to get a closer look.  They were my first certain Monarch sighting of the season.

Monarch on Common Blackberry (Rubus allegheniensis)

Monarch on Common Blackberry (Rubus allegheniensis)

The Monarchs weren’t alone. Little Wood Satyrs flitted about, occasionally stopping to drink nectar from the flowers.  Little Wood Satyrs are often found where woodlands meet meadow habitat.

Little Wood Satyr on Common Blackberry (Rubus allegheniensis)

Several Red-banded Hairstreaks visited the flowers, along with a few Zabulon Skippers, Eastern Tiger Swallowtails, and Silver-spotted Skippers.

Red-banded Hairstreak hanging out on Common Blackberry (Rubus allegheniensis)

Eastern Tiger Swallowtail drinking nectar from Common Blackberry (Rubus allegheniensis)

Zabulon Skipper drinking nectar from Common Blackberry (Rubus allegheniensis)

Bees and Common Blackberry have a mutually beneficial relationship. Bees are important pollinators for Common Blackberry, and Common Blackberry is an important source of nectar and pollen for the bees.  While I watched, Mining Bees, Bumble Bees, Carpenter Bees and Honey Bees worked the flowers.

Mining Bee (Andrena species) with Common Blackberry (Rubus allegheniensis)

A different Mining Bee (Andrena species) with Common Blackberry (Rubus allegheniensis)

Female Bumble Bee (Bombus species) foraging on Common Blackberry (Rubus allegheniensis). Notice the huge orange load of pollen she has harvested to take back to her nest to feed her larvae.

Eastern Carpenter Bee (Xylocopa virginica) with Common Blackberry (Rubus allegheniensis).

A pair of soldier beetles, Pennsylvania Leatherwings (Chauliognathus pensylvanicus) were mating at the same time the female impressively foraged the flowers for food, a pretty common beetle behavior combination.

A pair of soldier beetles, Pennsylvania Leatherwings (Chauliognathus pensylvanicus) mating, at the same time the female impressively forages Common Blackberry flowers for food.

A Flower or Syrphid Fly (Toxomerus geminatus) ate pollen from the flowers, probably not helping very much to pollinate the Blackberries.  Flies, bees and even beetles all consume some of the pollen.  Only about 2% of pollen is actually used for pollination. The rest serves as an enticement to flower visitors.

A Flower or Syrphid Fly (Toxomerus geminatus) eats pollen from Common Blackberry (Rubus allegheniensis) flowers

A Flesh Fly, and a Robber Fly disguised as a Bumble Bee paused on Blackberry leaves. As a carnivore, the Robber Fly’s mission is to capture and eat other insects.  The disguise may help it elude predators and seem harmless to its intended prey.

A Robber Fly ( Laphria flavicollis) pausing on a Common Blackberry (Rubus allegheniensis) leaf

A Flesh Fly (Sarcophaga species) on Common Blackberry (Rubus allegheniensis)

At a woods edge location nearby in New Jersey, a Bumble Bee and Orange Sulphur enjoyed the nectar the Blackberries offered.

Bumble Bee (Bombus species) on Common Blackberry (Rubus allegheniensis).

Orange Sulphur drinking nectar from Common Blackberry (Rubus allegheniensis).

Common Blackberry has high value for other animals. The insect flower visitors will help to ensure a late summer feast of blackberries for birds, and mammals from mice to fox, and even bear.  They’re very healthy for humans, too!

Ripe fruit of Common Blackberry (Rubus allegheniensis).

Wild Turkey is one of the many animals that benefit from eating Common Blackberry (Rubus allegheniensis) fruit

During the summer, these Common Blackberry brambles offer the perfect nesting habitat for Indigo Buntings. I saw a flash of blue feathers heading for a nearby tree, so they may already be in the process of establishing their nesting territory.

Male Indigo Bunting in Eastern Red Cedar

Multiflora Rose (Rosa multiflora), another Rose family member, is also in bloom.  This species was introduced from Asia for use in hedgerows, especially around farm fields.  As is so often the case, it turned out the introduction was a bad idea.  Multiflora Rose has since become invasive in much of the United States and Canada.  Several states list it as a noxious weed, and some prohibit it.

Plants and even animals that are introduced in a location far from where they evolved often become a problem in their new environment, since the natural predators with which they evolved are not present. In their native locations, these predators help to keep the plant or animal population in balance with other species.  Without these natural checks, the introduced species can crowd out the native plant species on which the animals with which they evolved depend.  We end up losing both plant and animal species as a result.

There is a family resemblance between Common Blackberry and Multiflora Rose, but it’s fairly easy to tell them apart.

Common Blackberry (Rubus allegheniensis) flowers

Common Blackberry flowers are usually white, about 1-1 ½ inches (2.54-3.8 cm) in diameter. The petals have rounded tips.  A large cluster of greenish pistils, the female reproductive flower parts, are visible at the center of the flowers.  These pistils together produce an aggregation of tiny fleshy fruits (called druplets) that are what we know as a blackberry.  The fruits start out green, turning red and eventually black when they’re ripe.  The stamens (male reproductive parts) surround the pistils.  They have white filaments topped with brownish anthers from which pollen is released.

Multiflora Rose (Rosa multiflora) flowers

Multiflora Rose flowers are also usually white, or rarely pinkish. They are just a bit smaller, and the tip of each petal is notched, not rounded.  There is a single greenish pistil at the center of the flower that produces a single round red berry-like fruit called a hip. The pistil is surrounded by stamens with creamy yellow filaments and darker golden anthers.  Multiflora Rose leaves have a distinctive fringe along the sides of the base of the stem.  This is not present in Common Blackberry.

Where I have seen Common Blackberry and Multiflora Rose in close proximity to each other, the pollinators always choose Common Blackberry. It may be a small sampling for a scientific study, but it seems like a pretty telling endorsement to me!

Eastern Tiger Swallowtail drinking nectar from Common Blackberry (Rubus allegheniensis)

Related Posts

Indigo Buntings – Living on the Edge!

For Information on Meadow Maintenance from the Xerces Society


Mader, Eric; Shepherd, Matthew; Vaughan, Mace; Black, Scott Hoffman; LeBuhn, Gretchen. Attracting Native Pollinators: Protecting North America’s Bees and Butterflies. 2011.

The Xerces Society


Cech, Rick; Tudor, Guy. Butterflies of the East Coast.  2005.

Eaton, Eric R.; Kauffman, Ken. Kaufman Field Guide to Insects of North America.  2007.

Evans, Arthur V. Beetles of Eastern North America.  2014.

Mader, Eric; Shepherd, Matthew; Vaughan, Mace; Black, Scott Hoffman; LeBuhn, Gretchen. Attracting Native Pollinators: Protecting North America’s Bees and Butterflies. 2011.

Marshall, Stephen A. Insects Their Natural History and Diversity. 2006.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania.  2007

Illinois Wildflowers

USDA NRCS Database

Lady Bird Johnson Wildflower Center

For Information on Mutiflora Rose

USDA NRCS Database

USDA National Invasive Species Information Center

Center for Invasive Species and Ecosystem Health