The Arboretum, University of Guelph

Music Among the Trees!

Join us for The Arb Expo Kick-off Event on Friday, September 11, 2026, 6:30 PM - 8 PM at The OAC Arboretum Centre featuring music by Canadian singer-songwriter Katherine Wheatley!

Enjoy a special sunset evening surrounded by nature with live music, snacks and beverages, a raffle, and an exclusive opportunity to preview the plant sale ahead of The Arb Expo: Tree Day + Plant Sale on Saturday.
The tickets also include the opportunity to purchase one plant ahead of the plant sale.

Links in the bio and here:

-Tickets: $20 +HST
https://uogarboretumshop.ca/collections/event-tickets/products/arb-expo-2026-friday-night-music-among-the-trees

-Katherine's Website: https://katherinewheatley.com/bio.html

-Arboretum Expo Information: https://arboretum.uoguelph.ca/education-events/ArbExpo

About the artist: Katherine Wheatley
It has been 35 years since Katherine Wheatley sold her first four-song cassette, gave her first radio interview, and performed at her first folk festival. Since then, she has appeared in duos, trios, and bands across Canada, the United States, and Europe. As a musician and adventure guide in Antarctica and the Arctic, Katherine learned more than 400 cover songs while becoming well acquainted with the habits of whales, penguins, polar bears, and even icebergs.

Today, she tours as a solo artist, with the duo Wendell and Wheat, and with the trio Boreal, which was nominated for three 2026 Canadian Folk Music Awards. Alongside Jane Lewis, Katherine also leads regular choirs and co-directs the twice-yearly Women's Music Weekend retreat in Guelph. Known for her deep, earthy voice and expressive guitar work, Katherine creates music rich in rhythm, warmth, colour, and melody.

“A transcendent concert...a truly Canadian original.” — CHRONICLE JOURNAL, Thunder Bay, ON

This event supports the annual Arboretum Expo, celebrating nature, people, and the connections that bring them together.



Photo: Informative text about the event: Music Among the Trees - Arb Expo Kick-off event with Katherine Wheatley and a photo of the artist

Let's meet Ohio Buckeye!

It is the time of year that Ohio Buckeye - Aesculus glabra- really stands out, as the large (not culinary) nuts become obvious. These are enclosed in an erratically prickly, sandy brown rind or shell. Ohio Buckeye does very well in low-pH, calcareous soils, and it is closely related to the more commonly planted horse-chestnut, but is native to the midwestern U.S.A., just squeaking over the border into Ontario. Squirrels seem to enjoy planting these, and we are constantly discovering them in new and surprising places in the collections.

In The Arboretum, you can find them in the Native Trees loops and in the World of Trees. The leaves are compound leaves, usually with five pointed leaflets spreading out from the central petiole, and often by late summer they can look a little worse for wear, with scorched spots (entirely cosmetic) from the heat and wind. These small trees have a nice rounded canopy with pale, bumpy bark.



Photos:
1. Ohio buckeye seed
2. Ohio buckeye solitary
3. Ohio buckeye canopy
4. Ohio buckeye leaf
5. Ohio buckeye pale grey bark
6. Ohio buckeye seed and jumping spider

Photos and text by Polly Samland, Collections Horticulturist and Plants Records Technologist

Arboretum iNaturalist Firsts!
These are just some of the species our naturalist team found over the summer that were the first to be posted on our iNaturalist project (linked below and in our bio)!
There are new species to be found every day, especially when you aren't looking for them!

Let us know if you have seen any of these guys around The Arboretum! Happy hunting!

U of G Arboretum iNaturalist Project: https://www.inaturalist.org/projects/university-of-guelph-arboretum



Image description: A series of images of new species to be posted to The Arboretum iNaturalist project. The species are as follows:
1. Three-spotted Horse Fly (Joseph Langlois), Northern Pine Tussock Moth (Chris Earley), and Texas Leafcutter Bee (Ben Hartshorn)
2. Eastern Thistle Longhorn Bee and Acutalis tartarea (Ben Hartshorn)
3. Poecilanthrax tegminipennis and Grapeleaf Skeletonizer Moth (Ben Hartshorn)
4. Green-bronze Dung Beetle (Roderick Hornby), Scaly Chanterelle (Ben Hartshorn), and Long-haired Leafwalker (Lilly Curtis-Norcross).
Text (slide 4): Imperfect Finds: Not all new finds are obvious, and you may not always get good pictures, but they can still count! This dung beetle was found by a kid during our gryph camp!

It's Wacky Wildlife Wednesday at The Arboretum!
Here are some examples of weird and wonderful wildlife spotted by our naturalists this summer:

1: Acraspis prinoides is a species of cynipid gall wasp that creates bizarre-looking plant galls to house its young. Galls are formed by the host plants themselves after gall-inducing organisms force them to alter their growth, meaning that this gall is actually part of the tree! This gall was found on Chinquapin Oak on our west Native Trees of Ontario loop.

2: These Clavate Tortoise Beetle (Plagiometriona clavata) larvae look like something you would expect to find on the ocean floor. Their flat body shape and spiky projections help them carry a mass of their own shed skin and f***s on their backs, which helps them stay camouflaged and protected from predators. These larvae were found near the J.C. Taylor Nature Centre!

3: This bee doesn't seem wacky at first... until you take a closer look and realize that it isn't a bee at all! This is a Boreal Laphria (Laphria posticata), which is a species of bee-mimic robber fly. Many fly species mimic the warning colours of stinging bees and wasps to ward off predators. The Boreal Laphria takes its mimicry one step further: it uses its appearance to fool unsuspecting insects so it can catch and eat them! This robber fly was found in our Gosling Wildlife Gardens.

4: Dead Man's Fingers (Xylaria polymorpha), named for its resemblance to fingers reaching from the ground, is a species of creepy-looking fungus that grows on decaying wood. Like many other species of fungi, it plays an important role in forest ecosystems by helping to break down organic matter and return nutrients to the soil. These fungi were found in Mtigwaaki Forest!

5: The long antennae of this Red Milkw**d Beetle (Tetraopes tetrophthalmus) seem to have split its compound eyes cleanly in half! While this species appears to have four eyes, each pair of "half eyes," is actually separate lobes of the same compound eye. This beetle was found on Common Milkw**d growing along the Ivey Trail!



Photos: Ben Hartshorn.
Text: Ben Hartshorn and Lilly Curtis-Norcross, Summer Naturalists

What's in bloom this week? Nodding onion, Virgin's bower, Large-leaved aster, Purple Joe-pye w**d, Smooth oxeye, Dense blazing-star, Garden phlox, Grey-headed prairie coneflower, Black-eyed Susan, and New York ironw**d!

1. Allium cernuum - Nodding onion (Location: Gosling Wildlife Gardens)
2. Clematis virginiana - Virgin's bower (Location: Gosling Wildlife Gardens)
3. Eurybia macrophylla - Large-leaved aster (Location: Gosling Wildlife Gardens, Roots and Shoots Garden)
4. Eutrochium purpureum - Purple Joe-pye w**d (Location: Gosling Wildlife Gardens, Roots and Shoots Garden)
5. Heliopsis helianthoides - Smooth oxeye (Location: Gosling Wildlife Gardens)
6. Liatris spicata - Dense blazing-star (Location: Gosling Wildlife Gardens)
7. Phlox paniculata - Garden phlox (Location: Gosling Wildlife Gardens)
8. Ratibida pinnata - Grey-headed prairie coneflower (Location: Gosling Wildlife Gardens)
9. Rudbeckia fulgida var. sullivantii 'Goldsturm' - Black-eyed Susan (Location: English Garden)
10. Vernonia noveboracensis - New York ironw**d (Location: Gosling Wildlife Gardens)

Snap a photo? Tag The Arb!
Note: Please keep to the designated pathways and lawn areas to protect blooms. Do not climb the trees, pick or prune plants, or step in plant beds. Thank you!



Photos by Head Gardener, Cael Wishart

Already finished our second week of Arboretum Gryph Camp! Time flies!

Thanks to the campers for being so keen and curious, and thank you to Gryph Camps for coordinating and letting us be a part of your team!

Looking forward to seeing you all next year!



Photo: A scrapbook-style selection of Arboretum critter pictures including: American Toad, Eastern Common Garter Snake, Pigeon Horntail, Northern Dog Day Cicadas, Mushrooms, A Lined Orbweaver, and insect markings. Text: Arboretum Gryph Camp: Hidden Life Edition!

Photos by: Roderick Hornby, Ben Hartshorn, and Lilly Curtis-Norcross

Incredible caterpillar diversity at The Arboretum!

Caterpillars are everywhere in The Arboretum this summer, sporting a wide variety of shapes, colours, and survival strategies! Many caterpillars, like the Monarch (photo 6), use their bold patterning to warn predators that they are toxic to eat. Other caterpillars, like the Eastern Giant Swallowtail (photo 8), use their colours to disguise themselves as something unappetizing.

Don't be fooled by the Eastern Tiger Swallowtail (photo 1); those are not their real eyes! They have evolved eyespot patterns to trick predators into thinking they are a bigger and more dangerous animal, like a snake. When they feel threatened, they can shoot out a bright orange organ called an osmeterium from the front of their head that is forked like a snake's tongue!

Caterpillars consume a massive amount of plant biomass in forest ecosystems, and are a vital food source for birds, mammals, and other insects. Without them, the food chain would collapse!



Photo 1: Eastern Tiger Swallowtail (Papilio glaucus)
Photo 2: Cottonwood Dagger Moth (Acronicta lepusculina)
Photo 3: Admiral sp. (Genus Limenitus)
Photo 4: Waved Sphinx (Ceratomia undulosa)
Photo 5: Hickory Tussock Moth (Lophocampa caryae)
Photo 6: Monarch (Danaus plexippus)
Photo 7: Definite Tussock Moth (Orgyia definita)
Photo 8: Eastern Giant Swallowtail (Papilio cresphontes)

Photos by Ben Hartshorn.
Text by Ben Hartshorn and Lilly Curtis-Norcross, Summer Naturalists

This week, let's meet Hydrangea quercifolia, also known as oakleaf hydrangea!

True to its name, this hydrangea has beautiful leaves that look remarkably like those of an oak tree. And these leaves are quite big for a shrub species, which can reach roughly 20 - 30cm long! Emerging leaves from this species are almost yellowish, turning to a vibrant green as they mature. Right now, you can start to see some leaves beginning to transform to shades of red, burgundy, bronze and purple. Next month, you will really start to see how striking these leaves become once they fully turn colour.

You will also notice that the flowers change colour as they age towards the end of summer. These large, cone-shaped clusters will open white, gradually turn pink, and eventually become tan/brown as they dry in the winter. Now is a great time to view the contrast between old and new flowers, offering a rich diversity in colours on a single plant. It is certainly a remarkable species that displays beautiful colour variations throughout the different seasons. Oakleaf hydrangea is also one of only two hydrangea species with cone-shaped flower clusters, rather than the rounded spherical blooms people often associate hydrangeas with.

The Arboretum has several specimens of oakleaf hydrangea, which can be found in the World of Trees and the Katsura Collection!



Photos:
1 Hydrangea quercifolia (oakleaf hydrangea) green leaves with some changing colour
2 Hydrangea quercifolia (oakleaf hydrangea) flowers changing colour
3 Oakleaf hydrangea green leaves
4 Oakleaf hydrangea leaves and flowers changing colour
5 Oakleaf hydrangea leaves changing colour

Photos and text by Cael Wishart, Head Gardener