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Winter Tree ID Tips

Polly Samland, Horticultural and Plant Records Technologist

When learning to identify a tree or shrub, there is rarely just one feature to look for. When one key feature exists - a particular seed or flower part - it can be quite fleeting or seasonal. Familiarity with the iconic white bark of a paper birch won’t help you recognize it as a young sapling.

More often, you need to find a combination of traits. In winter, fewer will be present (although these may be easier to see). Look for branching arrangement and bud appearance, leaf scars, bark characteristics like lenticels and pubescence, the general habit or form of a plant, and lingering fruit. Never just photograph one feature, try to capture all the information that could possibly be useful.

colour photo of the remnants of elderberry fruit on the twig of an elderberry shrub in wintercolour photo of the bark of an elderberry shrub

The buds, fruit remnants, and bark of an elderberry shrub.

We often learn to separate out the opposite-branching from the alternate, as a simple first step. This narrows down the choices (for plants native to Ontario) to ash, maple, and shrubs like dogwood, elderberry, viburnum, bladdernut and euonymus.

Along the Eramosa river, I see the large trees with many thick sprawling trunks leaning in all directions, holding their dried samaras well into the winter, and I immediately think, oh Manitoba maple (Acer negundo), without really checking further. Without the seeds present it may be hard to tell apart from a big hybrid willow, which have similar habitat and form, and then looking for opposite or alternate buds makes the distinction easy.

It is always important to think about where you are, not just the habitat or circumstances that the plant is growing in but the likelihood that the plant is naturally occurring, spontaneous or planted. Many field guides won’t list the foreign species that exist all around us.

Considering maple (Acer), native species and ornamental or landscape species co-exist in our parks and neighbourhoods. Selections of Norway maple (Acer platanoides) were used as street trees for decades and have seeded prolifically throughout backyards and into trails and suburban edges. To tell a Norway maple from a sugar maple (Acer saccharum) in winter, you can look at both the buds and the bark. The Norway maple trunk often has a very regular texture, while the sugar maple will have smooth plates and small ridges in a carefree, freeform style up the trunk.

close up colour photo of the bark of a tree with even ridgesclose up colour photo of the bark of a tree with longer irregular ridges and smooth areas
The bark of a Norway Maple (Acer platanoides) (left) and a Sugar Maple (Acer saccharum) (right).

The sugar maple also will have smaller, pointed buds with more scales on the terminal bud.

close up colour photo of the buds of a norway maple treeclose up colour photo of the buds of a sugar maple.
(Norway maple and sugar maple bud photos)

Winter is a good time to get to know your plant neighbours. My advice is to get familiar with one plant at a time. Working up from the bud shape to the habit, memorize the combination of features that form a species and you will see the different roles it plays in your landscape and community.

For more particulars on winter woody plant id, we're offering a virtual tree and shrub identification course in February. Check out this course, along with our other workshops below!

Top: The buds, fruit remnants, and bark of a sambucus shrub. Middle: The bark of a Norway maple next to the bark of a sugar maple. Bottom: The buds of a Norway maple next to the buds of a sugar maple. All photos by Polly Samland.

Upcoming Workshops


Colour photo of 8 different images of birds arranged in a grid with a black centre square with white text that says bird sounds

Virtual Bird Songs
Join Chris Earley, Arboretum Interpretive Biologist for a series of eight virtual noon-hour lectures to cover over 150 bird species! We will focus on songs and some common, distinctive calls and will apply different methods to remember them. Learn how to make your own calls, read a sonogram, make up your own memorable bird song sayings and more! Registration is still open until early February and all participants will have access to recordings, so you can watch the sessions on your own time. Jan 17-26

Colour photo of an animal track in snowVirtual Introduction to Tracking Ontario Mammals
Who left that track in the snow? This introductory tracking workshop will help you identify differences in track patterns for some common mammals that live in Ontario. Jan 19

colour photo of a bird with a speech bubble that reads bring your garden and nature questionsAsk The Arb
Noon-hour session covering Q&A topics from horticulture to birding. Whether you're worried about a plant in your garden or curious about an odd bird behaviour, join interpretive and horticultural staff for a monthly discussion. Jan 25


colour photo of animal tracks in snow

Virtual Tracks, Signs, and Scat
Animals can sometimes be tricky to see but they are always leaving stories about their lives for us to find. In this tracking workshop, we will look at tracks, scat and sign for a variety of Ontario mammals. By looking at these clues, we can piece together mysteries that bring us closer in our connection with the wild beings of the meadows, forest and shorelines. Jan 26

photo of a night sky framed by silhouettes of treesVirtual Constellation "Walk" with Trevor Chandler
Join us for monthly sessions as we get to know the night sky a little better. Participants will be introduced to prominent stars and constellations, where to look for them and how the motions of planet Earth cause them to appear to shift from hour to hour and month to month. You will receive a downloadable star map to help you make your way through the stars. Jan 27

A colour watercolour painting of a snowy landscapeSnow in Watercolour
In this virtual beginner friendly workshop, Candice Leyland will demonstrate a variety of techniques to capture snowy landscapes in watercolour. During the second half of the class, she will work with students step by step to create a simple snowy winter scene. A supply list is provided upon in your confirmation. Please ensure you have the supplies on hand for the workshop. Jan 31

Colour photo of a twig against a sky backgroundVirtual Winter Tree I.D. with Shelley Hunt
No leaves? No problem! In this workshop you will learn about the variety of tree features that are useful for winter identification of deciduous trees as well as evergreens. We will focus on native Ontario tree species. Optional 'homework' assignments will encourage you to get outside and observe trees in between sessions. The program runs once a week for 4 weeks. Starts Feb 3

colour photo of a man in a brown coat and jeans measuring animal tracks in the snow
In-Person Tracking
Come and learn about animal tracking in a hands-on workshop at the Guelph Arboretum. We will look for tracks, scat and signs for a variety of Ontario animals. Dress in layers to be outdoors. Wear comfortable, warm boots. Recommended: Bring a notebook and a measuring tape to help with track identification. Feb 6

colour image of a digital rendering of a gardenVirtual Wildlife Garden Design Course
Learn how to design a diverse garden space that attracts native wildlife species through key design elements, plant choices and maintenance needs. This course will draw from concepts found in The Arboretum’s Gosling Wildlife Gardens. Participants discover the relationships between plants and wildlife and how these ideas can be applied to a backyard! Feb 8 and 9

colour photo of a man in a gardenVirtual My First Vegetable Garden With Robert Pavlis
This course is designed for the new gardener or one that has only been growing vegetables for a couple of years. The course starts at the very beginning, with ordering seeds and ends with a detailed discussion of the 10 best vegetables for new gardeners. Robert is a Master Gardener and garden writer who runs two popular gardening blogs and has published several gardening books. Starts Feb 15

colour photo of a japanese garden
Virtual Japanese Garden Design Course
Taught by our Head Gardener Cael Wishart, this introductory course to Japanese garden design covers the traditional techniques used to establish gardens of peace and Zen. These gardens require a high attention to detail in both design and maintenance. Wherever your interest lie, in theory or in practice, this course is intended to help you appreciate and understand this unique tradition. Mar 8

colour photo of a man standing in front of a garden
Virtual Gardening Fundamentals With Robert Pavlis
Garden Fundamentals will focus on ornamental gardens including trees, shrubs, perennials, bulbs and grasses. The course will cover practical topics such as planting, maintenance, plant selection, sun requirements, and Robert will give you some of his top picks. This course is suitable for the beginner and intermediate gardener. Starts Mar 15

A colour photo of a red handled pair of secateurs held in front of tree barkThe Art and Practice of Pruning
This half-day indoor/outdoor practical in-person workshop teaches the principles of easy and correct pruning in the home landscape. Participants learn how to choose the right equipment and how to keep it sharp and clean. Pruning techniques will be shown and practiced on a variety of shrubs and small trees. Mask, proof of vaccination and screening required to attend this event. Mar 22

All of our virtual programs are offered live on Zoom, and recordings are made available for registrants to access for a limited time. Visit our website to learn more about these and our other programs. Register early to save your spot!

Who's whoo? Getting to know Ontario owls!

Michelle Beltran, Naturalist Intern

Winter is in full force these days. If you take a quick peek outside, the frosty air and snow may entice you to stay inside. Despite the weather, lots of critters remain active at this time of year, including owls. Don’t let an owl’s handsome face and charming eyes fool you: owls are impressive predators capable of not only surviving but also reproducing during our frigid winters. The excitement of encountering an owl in nature never gets old. Luckily for us, winter can be a great time to observe these awesome animals! 

It may seem odd to describe Southern Ontario as anyone’s preferred winter destination, but the open farm fields found on the outskirts of Guelph make great Snowy Owl habitat. An attentive car ride along open fields may reveal little snowmen. Snowy owls will blend in perfectly in a snow-covered field, looking like little piles of snow. Upon closer inspection, you might find that the white bundle sitting in the field is in fact a Snowy Owl! Remember to respectfully observe any owl you find in nature from a distance to avoid disturbing it.   

colour photo of a snowy owl sitting in a snowy field
Great Horned Owls are one of the most common species of owls you can find in Guelph. Their camouflage does an amazing job of disguising them as part of the tree they roost in. While Great Horned Owls are difficult to find, timing your search with when they are more active may help you see or hear them. Great Horned Owls are crepuscular, meaning that they are most active at dawn and dusk.  colour photo of the silhouette of an evergreen tree with an owl perched on top of it against a sunset background
Colour photo of a little brown owl perched in a hole in a dead tree

One of the smallest species of owl you’re likely to find in Guelph is the Eastern Screech-Owl. They are another master of disguise and camouflage beautifully into their surroundings. They can often be seen nestled into the crooks and cavities of trees. On warm sunny days, you might find Eastern Screech-Owls peeking out from the hollows they roost in.  
colour photo of a large brown and white owl with long feathers arranged to look like horns on its head perched in a tree

Long-eared Owls are some of the most secretive owls. They prefer to spend their day hidden deep in the cover of foliage. Finding Long-eared Owls during the day often requires extensive searching. Another way to find out if there are Long-eared Owls in your area is to conduct an owl prowl. Owl Prowls are nocturnal bird surveys. The objective is to take a stroll at night through the habitat that you suspect owls may be living in and listen for their calls. Many owls breed during the winter. Every owl species has their own unique call that they’ll use to attract mates and define their territory.

Photos credit/descriptions First Photo: A Snowy Owl sitting in a snowy field. Photo by Karl Egressy. Second Photo: A Great Horned Owl perched on top of a tree. Photo by Michelle Beltran. Third Photo: An Eastern Screech Owl roosting in a cavity in a tree. Photo by Michelle Beltran. Fourth Photo: A Long-eared Owl roosting in a tree. Photo by Chris Earley.

What To See

To learn more about what is happening or what to look out for at The Arboretum please follow us on social media. We are on Instagram, Facebook and Twitter. Search for us at @uogarboretum.
[Click on the photos below to see the posts and more on Instagram.]

a colour photo of a drawing of a moth with wings made of real leaves and antennas made of cedar Want to add some nature fun to your day? Get crafty! Try using pieces from nature to create your own nature artwork, like this butterfly. How many different creatures can you make with just a few leaves, twigs, or even pebbles?

In order to protect our natural spaces, please only collect small pieces from the ground and not from live plants.

Colour photo of squirrel tracks in the snowIt’s great tracking weather outside! When you’re out enjoying nature, this is your reminder to keep an eye on the ground for neat little signs that the critters outside are leaving behind!

Galloping animals like squirrels tend to leave tracks in patterns like this. The smaller prints in the back are from their front feet hitting the ground first; then their larger back feet swing around and land in front. They then push off with those back feet and they’re off again!

colour photo of green cedar leaves Here in Ontario, most trees can be easily divided into two groups: evergreen and deciduous. Evergreen trees are green all year round, while deciduous trees lose their leaves in the winter.

Ready to get outside for a winter nature challenge? The next time you’re visiting The Arboretum or going for a walk in your neighbourhood, see if you can find 3 different types of evergreen trees and 3 different types of deciduous trees! Can you identify them all? Which one is your favourite?


From the Collection: The Dwarf Conifers

Sadie Campbell, Horticultural Intern

Even in the middle of winter, there’s still plenty to see in The Arboretum. If you’re looking to add some colour and texture to your winter walk, our Dwarf Conifer Collection is the perfect place to explore. With over 150 specimens, this collection highlights the variety of form, colour, and habit of dwarf conifer trees and shrubs.

colour photo of dwarf conifers on a misty morning
The word conifer is a compound of the latin words conus (cone) and ferre (to bear), meaning “cone bearing”. Conifers are very old, actually predating the emergence of flowering plants. The cones are how these plants reproduce, with wind carrying pollen from male to female cones, rather than the insects and birds that pollinate many flowering plants. Conifers have female seed-producing cones, which are usually woody, and male pollen-producing cones that are usually herbaceous and less conspicuous. Conifers can be monoecious, with male and female cones appearing on distinct parts of the same plant or dioecious or sub-dioecious, with male and female cones always or usually appearing on different plants. Most conifers, like spruce, pine, and fir produce the kind of female cones you picture when you think of conifer cones, with woody scales that enclose the seeds, while others, such as junipers and yews, produce more unusual cones. Junipers (Juniperus) tend to have cones with fleshy, fused scales that look like berries. The female cones of yews (Taxus) are comprised of a single seed surrounded by a singular scale that develops into a fleshy aril, which is an attractive food source for fruit-eating birds.
colour photo of a spruce cone hanging from a tree branchcolour photo of juniper berries on a branchcolour photo of the red arils and green seeds of a juniper

Dwarf conifers are slow growing conifers that do not reach the same size as wild conifers of the same species. Some dwarf conifers are naturally short species, like the Canada yew (Taxus canadensis), but most are cultivars are bred by horticulturalists. Many dwarf conifers are originally derived from a growth condition called a witch’s broom. Witch’s broom is a condition where deformed twigs grow very compact and dense, resulting in a bird’s-nest like mass of twigs or branches in a tree. Witch’s brooms can look like a ball of branches and twigs or sometimes like a dwarf version of the tree it is growing on.
colour photo of a witch's broom growth on a tree
Witch’s brooms can occur on pretty much any type of plant but are most associated with conifers. They can occur as a result of either genetic mutation or by external interference from things like fungi, insects, nematodes, or viruses. When a witch’s broom is caused by genetic mutation, the unique traits of the mutated twigs can usually be replicated through propagation. Horticulturalists propagate witch’s brooms either by grafting or from rooting cuttings, which means that the cultivated plant will have the same bizarre genetics as the witch’s broom. Aside from compact and slow growing habit, witch’s brooms can also have interesting colour variations, resulting in some very vibrant cultivars!

If you’re looking to add some structure, texture, and winter interest to your garden, our Dwarf Conifer Collection is a great place to explore the diversity of conifers. None of our dwarf conifers are clipped, so they have been allowed to grow into their unique natural forms. Our collection is organized by genus, with beds featuring species and cultivars from the same genus all grouped together. As you walk through this collection, pay special attention to the variety within each genus, as well as between the different genera. In the Thuja section, different cultivars of the eastern white cedar (Thuja occidentalis) present a range of colours and forms, like dense, dark blue-green twisting foliage of ‘Umbraculifera’ or the weeping, thread-like leaves and branches of ‘Filiformis’. When you examine the different genera, you may also notice the similarities within a genus and the things that make each genus distinct, like the deciduous foliage of Larix or the berry-like cones of Juniperus. To learn more about this collection, visit our Dwarf Conifers webpage, and be sure to spend some time here on your next visit to The Arboretum!
colour photo of a close up of thuja foliagecolour photo of weeping thuja leaves

Photo credit and description. Top: The Dwarf Conifers on a misty morning. Photo by Chris Earley. Second Row: Photo of Picea mariana cone by Sean Fox. Photo of Juniperus chinensis 'Maney' cones by Sadie Campbell. Photo of Taxus baccata cones by Didier Descouens. Third: Photo of a witch's broom by Sean Fox. Bottom Row: Photo of Thuja occidentalis 'Umbraculifera' foliage by Sadie Campbell. Photo of Thuja occidentalis 'Filiformis' foliage by Sadie Campbell.

Weddings at The Arboretum

a colour photo of a man and a woman in formal wear standing in the snow surrounded by snow-covered conifers
Did you know weddings take place at The Arboretum year-round? Every season presents a contrasting natural landscape with scenic views of formal gardens, trees, and trails unique to our world-class, newly renovated indoor reception space with barrier-free access.

For availability, rental rates and to schedule a tour, contact Dawn Ann Webster at 519-824-4120 ext. 54110 or

Photo by Brian Limoyo Wedding Photography.

Research Highlight

Over the past five decades, The Arboretum has been the site of hundreds of studies conducted by students, staff, faculty, and researchers from both the University of Guelph and external organizations. With over 400 acres of land encompassing plant collections, an untouched nature reserve, Gene Banks, and a plant propagation facility, The Arboretum has earned its reputation as a 'Living Laboratory'. Guelph students have the opportunity to experience outdoor field work and data collection, while we benefit by learning from their research and data. This month we want to highlight some of the amazing work done by undergraduate students in The Arboretum. The following studies were undertaken as part of a third year Lab and Field Work in Ecology course (BIOL 3010) under the direction of Dr. Christina Caruso and Dr. Ryan Norris, with additional help from Arboretum Research Manager Dr. Aron Fazekas. 

Tastes like home: Field Work students find introduced moths prefer introduced hosts
Alex Walmsley, Abigail McCarthy, Andrea Perez, and Tharane Banugoban, and Natasha Sawatzky

One unique attribute of the Arboretum is the inclusion of many closely related species from around the world. A team of undergraduate ecology students used this opportunity in the fall of 2021 to better understand where the invasive pest Lymantria dispar dispar (previously known as the gypsy moth) chooses to lay its eggs given a variety of options.

Since its introduction from Europe in 1869 L. dispar has become a serious threat to North American trees. The caterpillars of the moth feed on leaves and were responsible for defoliating 1.8 million hectares of Ontario forest in 2021 alone. As defoliation like this is uncommon in Europe, the students were curious to see whether there was an obvious preference for North American trees over European ones when both were available to inform management of this troublesome insect.

Flightless L. dispar females lay several hundred eggs in a cluster on host tree branches that survive winter and hatch the following spring. The team developed a method to count these egg masses on eight species of tree, four each from the maple and oak families and split between native and introduced from Europe. The online Arboretum Explorer tool was especially helpful in locating and identifying the 80 trees sampled in the study.

Results of our study revealed that L. dispar egg mass were more likely to occur in European trees, with the often-invasive Norway Maple being the favorite. This suggests that moths prefer trees they evolved with, and that the epidemic nature of L. dispar is perhaps not due to our trees being particularly vulnerable but instead a lack of natural controls such as predators and diseases.

The students hope that this work can help to guide how L. dispar is controlled in Canada and to help with pest management and planting strategies in significant collections such as the Arboretum.

Colour photo of a group o four students studying a tree.
BIOL 3010 Students counting L.dispar egg masses on an Arboretum Norway maple (Acer platanoides). Left to right: Alex Walmsley, Abigail McCarthy, Andrea Perez, and Tharane Banugoban. Not pictured: Natasha Sawatzky.
Effects of temperature and moisture on soil invertebrate abundance in response to cold weather
 Liam Wilson, Abby Pullen, Justin Rose, Katie Schankula, and Sarah Whittaker
Soil invertebrates such as earthworms, termites, and millipeds are an incredibly diverse group of organisms and make up a large portion of global biodiversity. Within the soil, these organisms function to maintain ecosystem services such as nutrient cycling and soil formation. Like most organisms, a number of environmental factors can influence where soil invertebrates inhabit and ultimately perform their important ecosystem roles. For example, soil invertebrates are thought to prefer habitats with increased moisture level because it prevents desiccation and makes their diet more easily digestible. While most of the information on soil invertebrate biology is collected during the summer months, little is known about how soil invertebrate abundance is affected by seasonal decreases in temperature. Understanding how abundance is affected by decreased temperature and other conditions is important for understanding the role that soil invertebrates play in ecosystems during the fall and winter seasons.

In our study, we wanted to examine the assumption that increased leaf litter depth increases soil temperature and determine how soil temperature and soil moisture affect soil invertebrate abundance during the fall. We hypothesized that a greater number of soil invertebrates would be found higher in the soil profile in areas with increased amounts of leaf litter due to increased soil temperatures. We also hypothesized that invertebrate abundance would be highest in plots with higher moisture contents. To conduct our experiment, 56 plots were selected within a 10m2 area in Wild Goose Woods within the Arboretum. In each plot, we measured the height of leaf litter, soil temperature, soil moisture, and invertebrate abundance.

Our results showed that that increased leaf litter depth did indeed increase the temperature of the soil profile. However, this increase in soil temperature did not affect the abundance of invertebrates within the soil. We also found that increased soil moisture (above 32%) significantly decreased the abundance of invertebrates. Recent research has shown that precipitation during in the fall months in North America is steadily increasing. Although the cause for this increased precipitation is undiagnosed, it is evident that it has negative impacts on soil invertebrate abundance. This decrease in abundance may affect the ecosystem services soil invertebrates can provide.

If you would like more information on research at The Arboretum, visit our Research & Conservation webpage. For further inquiries, please contact our Research Coordinator, Dr. Aron Fazekas at

In the Ecosystem

Want to learn more about native plants and biodiversity in gardening? Ohio State University is offering a free 6-session webinar series each Friday until February 11th. Each session features a different speaker discussing native plants. Watch them live at 10 am on Fridays, or watch the recordings on your own time! Follow this link to learn more and to register for this series.

As we begin 2022, take a moment to look back at some of the positive environment news stories from the past year. Species recovery, new green technologies, and new environmental protections are only some of the good things that happened in 2021. Check out this article for some positive news to start your year!

Virtual Wednesday Walks With Our Summer Naturalist

youtube screenshot of a chickadee perched on a bird feeder holding a seed in its beak

Even though it's January, there's still lots to see in our gardens. Join Michelle as she explores the winter plants in the Gosling Wildlife Gardens, and checks out some of the animal activity around our bird feeder!
screenshot of a youtube video showing a woman's hand resting on a birch tree
Our World of Trees Collection is home to trees from all across the Northern Hemisphere and is a great place to see similarities and differences in family groups. Join Michelle as she explores this diverse collection!

Donation and Dedication Opportunities

colour photo of a girl using an identification chart to identify a cedar with the words Support the Arb Give Today

The Arboretum relies on donations from generous supporters to keep our grounds beautiful and accessible every day, all year round. Gifts to the Arboretum are tax deductible, and enable efforts such as tree recovery, signage, trails, studentships, gardens, educational programs, and more! Join our community of supporters today with a gift through our online donation portal. 

Did you know that we can accept donations of shares and in-kind contributions? A gift of appreciated securities is a great way to support The Arboretum. Use the Notification of Gift of Securities form. Donors receive full tax credit for the fair-market value. Learn more about how you can give at

Donor Stories

colour photo of a red-breasted nuthatch holding a seed in its mouth, perched on a hand holding sunflower seeds in their shellsIn this new year, we want to highlight the contributions of our monthly donors.

Even amidst today’s uncertainty, The Arboretum stays open every day, all year round. Our grounds, boardwalks, trails, and gardens provide vital greenspace, open to everyone, for connection and conservation, for learning and well-being.

A sustaining monthly gift can meaningfully impact our community and the environment
in many ways. With as little as $5 a month, our regular donors support our goals in conservation, biodiversity, education, and providing spaces for people to connect with nature. If you enjoy The Arboretum and want to help us continue and expand our work, we invite you to consider becoming a monthly donor. Thank you for caring about The Arboretum.


colour photo of a 2022 standing desk calendar with a photo of a spider on the front coverNew year, new calendar! Need a way to keep track of all the cool workshops we're offering this year - or anything else that may be going on? Our 2022 Calendar features 12 months of photos taken on The Arboretum grounds. Each month highlights the different plants and animals that make their homes in The Arb, with beautiful colour photos and fun facts. Did you know that the gray treefrogs can change colour to camouflage with their surroundings? Learn something new every month!

Visit our Merchandise shop
to order today or to check out our other cool products and educational materials.

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camera icon for photo creditThe header of this month's newsletter is DESCRIPTION. Photo by CREDIT.