Horn Farm Center for Agricultural Education

Tag Archive: Black Walnut

Finding Wonder in the Smallest Surprises

Building biodiversity is a key component of regenerative farming. When nature inspires how we design our food systems, a colorful cast of characters is bound to follow. That’s why we’re always excited to spot an unfamiliar or eye-catching insect in the field!

Don’t be fooled by their small stature: insects can provide a lot of ecological insights. In documenting both new and frequent sightings, we’ll explore questions like: Who do they eat? Who eats them? What habitats do they prefer? What plants do they depend on? If some consider them a “pest,” why? Is the judgment valid? Might there be a missing check – a predator or parasitoid, say – that could quell their impact? The vast majority of insects – many say over 99% – are harmless or beneficial to humans, so it’s worth taking the time to better understand those with whom we share our garden and farm ecosystems.

The 2026 growing season has been no exception for spotting cool bugs with even cooler life histories. Below are a few of the latest visitors to greet our staff, students, and volunteers this year. As you’ll see, even the smallest creatures can fill us with wonder, giving us countless pathways to connect with our local landscape.

Walnut Sphinx Moth (Amorpha juglandis)

Walnut Sphinx Moth (Amorpha juglandis), photographed May 18, 2026

With so many black walnut trees surrounding our growing field, the name for this common moth came as no surprise. As caterpillars, walnut sphinx moths eat the leaves of black walnut (Juglans nigra) and related trees like butternut and hickories. Interestingly, they also consume hazelnut leaves. The Horn Farm’s multifunctional riparian buffer includes hundreds of American hazelnuts (Corylus americana) planted to protect sensitive land while producing edible nuts. So, if nothing else, the Horn Farm apparently provides pristine reproductive habitat for Amorpha juglandis!

But this quaint lepidopteran – belonging to the order of insects that includes butterflies, moths, and skippers – comes from surprisingly ferocious stock. Walnut sphinx moth caterpillars are known to thrash, bite, and even squeal when distrurbed. While the squealing reaches frequencies undetectable by the human ear, birds perceive the sounds and may become startled enough to skip the screaming caterpillars for their next meal.

But all this protest isn’t just pandemonium. Researchers have noticed how the caterpillar’s squeals resemble avian alarm signals, similar to those used by birds to communicate the presence of nearby predators. So it’s possible that the caterpllars are deflecting hungry birds by employing false alarms. Mimicry or chaos, this adaptation proves useful for keeping bird pressure at bay, allowing many caterpillars to survive the treacherous journey to becoming moths.

Eastern Elderberry Borer (Desmocerus palliatus)

American black elderberry (Sambucus canadensis), like American hazelnut, is a hallmark of the Horn Farm’s learning landscape. Dozens of class participants and volunteers have helped our team to plant, tend, and harvest hundreds of elderberries over the years, with the goal of creating a healthier farm ecosystem while demonstrating agroforestry to our community.

So, swimming as we are in a sea of elderberries, one would expect us to come across something like the eastern elderberry borer more often. This insect has an exclusive (or as ecologists would say, obligate) relationship with elderberry, requiring it for feeding and reproduction. But it turns out the elderberry borer is elusive, even for entomolgists. Many accounts describe it to this effect: “not uncommon, but rarely seen.”

The eastern elderberry borer is a species of longhorn beetle (Cerambycidae), and among the most visibly striking of this group. Its draping, iridescent wings are crowned with brilliant orange, a type of warning coloration designed to signal toxicity to birds and other predators. Some insects merely mimic warning coloration – like the viceroy butterfly vis-à-vis the monarch – but the elderberry borer may truly be noxious. Since elderberry leaves naturally contain toxic cyanogenic glycosides, the feeding insect can accumulate these toxins and render itself undesireable to predators. Cyanogenic glycosides, by the way, are the same compounds that make elderberry leaves and raw fruits inedible to people. They transform into hydrogen cyanide when consumed. When processing elderberry fruit for medicine, we have to cook or dry them to neutralize the toxins and reap elderberry’s incredible immune-boosting benefits.

Eastern elderberry borer (Desmocerus palliatus), photographed June 9th

Now, if an insect called a “borer” rings any bells, you may be thinking of the emerald ash borer (Agrilus planipennis). This recent newcomer to North America has decimiated ash tree populations. As the name suggests, borers burrow beneath the bark of their host trees, creating holes and tunnels while feeding on essential nutrients. But not all borers are built the same. While it’s true that the larvae of the elderberry borer carve tunnels through elderberry as part of their life cycle, healthy stands of elderberry are rarely overwhelmed. Thanks to a long history of co-evolution and the borer’s generally low populations, there isn’t reason to believe this visitor poses any major encumbrance to our goals. With vigorous elderberries in an increasingly diversified community of plants and food webs, the eastern elderberry borer is simply another member of the whole.

White-Marked Tussock Moth (Orgyia leucostigma)

White-marked tussock moth (Orgyia leucostigma), photographed June 20th

This whimsical caterpillar was found clinging to a willow leaf in our basketry willow plot, making for a third new sighting among the agroforestry plantings. In fact, a volunteer discovered it while we harvested willow stems for make-your-own flower crowns at our Summer Solstice Market!

We left this stem uncut, and keenly so. Despite its rather Seussical appearance, this caterpillar is known to cause contact dermatitis, even leaving a rash on sensitive skin. That’s because of the arsenal of barbed hairs found across it’s body. These are concentrated in the antennae-like structures portruding from both ends and the four puffed clumps lining its abdomen. Even the protective cocoons these caterpillars spin during metamorphosis can cause irritation when touched!

Unlike the pickier insects above, the tussock moth is a generalist when it comes to feeding. They’ve been documented eating the foliage of over 140 plant species, primarily trees, both deciduous and coniferous. In fact, when localized population surges do occur, they can be pinned as pests in orchards and tree farms. But outbreaks are generally limited to a single season, and a healthy mix of predators, parasitoids, and pathogens – encouraged by a diversity of plants – can help prevent incursions in the first place.

It might seem unusual that the female moths are naturally flightless, a condition called brachyptery. In a world where dispersing genetics is generally encouraged, doesn’t this pose a disadvantage? As it turns out, the caterpillars themselves compensate for this shortcoming. Thanks to their ability to create short strands of fine silk, very young caterpillars can make like balloons, catching a good breeze and floating to new feeding sites. Appropriately, this travel technique is called ballooning. And with well over a hundred plant species on their menu, tussock moths are bound to land someplace where they can find a bite to eat – like the willow patch at the Horn Farm.

Black Swallowtail Caterpillar (Papilio polyxenes)

Compared with the insects above, the black swallowtail caterpillar is a relatively common find during the summer. The same goes for its stunning adult form, often seen flitting among the pollinator plots planted by our Ecological Gardener Training Program students over the years. But despite its frequency, we’re always willing to pause and admire this charming visitor to our vegetable and herb beds.

Gardeners who grow plants in the carrot family, Apiaceae, likely share our familiarity with the black swallowtail. Caterpillars feed exclusively on members of this botanical grouping, which includes celery, dill, fennel, parsley, and, of course, carrot. Apiaceae also includes wild and feral kin to our garden staples. Alongside golden alexander, wild parsnip, and Queen Anne’s lace (or wild carrot), it’s not uncommon to find black swallowtail caterpillars nonchalantly dining on some of North America’s deadliest plants, like poison hemlock and water hemlock. As any forager knows, one being’s dinner could be another’s trip to the ER!

Like the white-marked tussock moth, the black swallowtail caterpillar packs a bigger punch than its appearance suggests. Lacking in hairy armor, it conceals a secret, smelly weapon. When threatened, the caterpillar can retract its head and expose a pair of orange horns called osmeteria. The bright coloration of these horns acts as a visual warning, and they emit a foul-smelling secretion that helps to repel attackers.

Black swallowtail caterpillar (Papilio polyxenes), photographed June 29th

While mature caterpillars employ this dramatic line of defense, younger caterpillars are a bit more subtle. Many people fail to recognize the early black swallowtail caterpillars as the same species, because they are very dark and spiny with a white splotch mark mid-way down their abdomen. These features may mimic bird droppings, helping them go undetected until they grow into their greener, more recognizable form. These incredible adaptations – visual, aromatic, and otherwise – help many caterpillars complete the perilous journey to pupation, after which they emerge as the iconic butterflies we associate with the summer.

Small Wonders Abounding

Growing food in ecological ways nourishes more than just the body. When we use nature’s designs to create diverse edible ecosystems, other benefits flutter, crawl, and inch our way. A lengthy summer day tending plants and harvesting food is always brightened when we find these signs of life. They may be small, but in filling us with curiosity, wonder, and admiration for the living world, they help to nourish our connection to the local landscape.

We’re grateful for the insects who surprise us each day. We’re also grateful for the students, volunteers, and other members of the Horn Farm community who share our fascination! Check out upcoming ways to get engaged with our educational ecosystem:

Ode to October

Looking Back on Fall Classes at the Horn Farm Center

Carpeting our land like the falling leaves, the Horn Farm’s autumn classes have come in all shapes, sizes, and colors!

Each weekend feels like exploring a new corner of our growing leaf pile. It’s times like these–dashing among the results of months of creative planning–that we get to enjoy the full diversity of this educational ecosystem.

Indeed, the Horn Farm’s mission to foster ecological learning and connect folks with the land is intentionally broad. There are as many ways to deepen our relationship with nature as there are leaves in a forest. And like the trees that bear these leaves, programs are both distinctly individual and richly interwoven.

Reflecting on the last few weeks, our community experienced foraging classes that incorporated art, art classes infused with foraging, and classes that combined growing, gastronomy, and wild gathering under one canopy.

Offerings have been and continue to be eclectic, but each learning experience is tethered by a goal to help each other (re)member what we’re truly capable of: that is, being resourceful, proactive, and attuned members of nature’s community.

Crafting Connection: Foraging for Art

September’s class finale was just a preview of October’s educational mosaic. In Goldenrod: Foraging & Botanical Dyeing, textile artist Chelsea Thompson–the creator behind earthencolor–joined our foraging educator Andrew to celebrate the splendid offerings of a seasonal staple, Solidago. Better known as goldenrod, Solidago was bursting with color as we walked to the wild meadow above our demonstration gardens to observe, connect, and harvest.

In the field, we covered tips for differentiating goldenrod species and illuminated some of the ecological and cultural relationships surrounding this native plant. We then gathered flowers to make medicinal goldenrod tea and transform the blooms into botanical dye. Chelsea provided insights on the basics of natural dyeing and walked folks through two styles–bundle dyeing and shibori, or tie-dye–extracting unbelievable colors from our harvest. While we waited for the dye to take, folks even got to enjoy pickled goldenrod shoots, experiencing a lesser-known use of this versatile plant.

The following week, we turned from pigments to printing.

In a craft that combines botanical study, personal expression, and meditation, community members explored the creative possibilities of the most unassuming aspects of plants. Seed heads, dried vegetables, sticks, and cones became artistic subjects in Kitchen Table Art: Printing with Plants, hosted by local nature artist Diane Podolsky.

In her own work, Diane combines rubbing, etching, and sketching to create stunning visual journals, drawing unexpected attention to the symmetries, patterns, and expressions of plants. Who knew that the bottom of a stalk of celery, a cross section of okra, a tassel of corn, or a bundle of pine needles could leave such an impression?

So, plant pigments, plant printing … now what? How about plant pressing?

October concluded with the second session of another new crafting topic, guided by Leah Robb of The Robb Wilds. Robb is an advocate for ecological gardens and native plants, and her recent hobby for collecting and preserving from her own garden has blossomed into a true love and talent for an ancient art, enough to approach us and propose her class The Art of Pressing Flowers.

In early September, students spent the first session of this program gathering fresh blooms and leaves from the Horn Farm’s fields. After six patient weeks of drying at home, they got to return and assemble their findings into one-of-a-kind “portraits of place.” Two blocks of wood, cardboard, paper, and time, it turns out, is all you need to transform fresh petals, leaves, and grasses into timeless gifts and mementos.

We also wrapped up October with another dip in the dye bath, this time focusing on the often overlooked black walnut (Juglans nigra). Unlike goldenrod and other floral pigments, which require a mordanting agent to anchor colors to textiles, the staining husks of black walnuts contain enough of their own tannins to produce a dye that adheres without prior processing. Any forager with weeks of walnut figures can testify to this!

And so, just as with goldenrod, we began Black Walnut: Foraging & Botanical Dyeing in the field, filling baskets with seasonal surplus for art-making and winter sustenance. Students learned how to collect, process, and crack black walnuts, in addition to seeing how the husks–often considered a waste product–can bring new tones to colorless textiles. As far as eating is concerned, it takes a few weeks for cleaned walnuts to cure in the shell before extracting the nut meats; so for supplying our class with plenty of cured nuts to crack and taste, we have to shout out helpers from our volunteer Community Crew!

From Creative Craft to Caring Culture

The creative possibilities that grow out of connection with the land extend beyond artistic craft.

Another new offering, which brought together biodynamic farmer Allen Clements of Dark Hollow Biodynamic and forager/photographer Sarah LeTourneau of @forest_apsarah, got us thinking about cooking, cultivation, and other creative relationships with nature.

In a detour from our usual focus on flora, Wild & Cultivated: Find, Taste, and Grow Your Own Mushrooms captured the full spectrum of ways we can appreciate the fungi among us. Following a foray through the Horn Farm’s woodlands that uncovered honey mushrooms, bracket fungi, and even a maitake, students learned how to bring our fungal allies home through cultivation, preparing logs and buckets with oyster mushroom spawn.

The class also featured a tasting of foraged and cultivated mushrooms, making for a full day of mycological meanderings!

So, from single plants to whole ecosystems, fall’s offerings shared just how generous the local landscape can be. There is certainly value in appreciating nature as observers, but connection that calls upon our hands, bodies, and creative energies is also important. Nature-based crafts remind us that we are part of the system, not separate from it. Humans have always influenced the ecologies around us–it’s the erroneous belief in our exceptionalism, in fact, that has caused us to stray and consume more than we return–but activities like craft, cultivation, and foraging help shed light on lost skills that are expressions of our caretaking roles. After all, when we know how to utilize local resources, we tend to their abundance, and live more regenerative lives.

Perhaps no program captured this spirit, and showcased the true creative possibilities of re-localizing our creativity, than October’s core offering: Coppice Agroforestry: Resprout Silviculture for a 22nd Century.

Dave Jacke–nationally-acclaimed agroforestry expert, ecological designer, and author of the tome Edible Forest Gardens–paid a visit from Massachusetts to provide our community with an evening lecture and full-day workshop on the ancient art of harvesting woody materials (think sticks, trunks, and twigs) from resprouting plants.

This time-tested style of agroforestry supported entire societies and economies, we learned, from Scandinavia and the British Isles, Northern Italy and Eastern Europe, to the Americas.

Between enlightening presentations on biology and history to observation in the Horn Farm’s own coppicing systems, Jacke introduced us to coppicing practices designed for local self-sufficiency. Indeed, historical precedent demonstrates how rotational harvests of woody plant materials can meet a vast range of community needs, filling countless creative niches. Biochar and mulch, medicine and livestock fodder, basketry and furniture, carriages and caskets, fencing and infrastructure–all are among the products of coppiced trees. All the while, these plants perform their usual ecological services, preserving healthy soil, filtering water, providing wind breaks and shade, and ensuring habitat for all members of the landscape.

It’s worth noting that, during his visit, Jacke also treated the Horn Farm’s staff to an educator’s workshop, helping us build momentum as we look to next year’s community offerings. Integrating concepts of ecological design with class planning, this experience was deeply introspective, moving, and activating for our team.

And so, we enter the winter feeling inspired, hopefully as much as the learners and land stewards who joined us this fall. Much time spent in this bountiful leaf pile has us itching with enthusiasm, and more creative play awaits in 2026!

Of course, fall isn’t over yet, and the offerings continue as the season winds down. These include the final sessions of our NEW Elements of Survival wilderness skills series and the Land & Peoples history series, hands-on classes on Sunchokes and Fire Cider, and an educational hike covering Winter Plant ID.

Check out these classes and more today!