I did it before I knew better. Or maybe it was a simple lack of willpower. Taking a cutting from a plant on public property is a no-no, but this was a pussy willow, a robust species that tolerates abuse and roots easily from cuttings. On the Bruce Trail near my home in Hamilton, Ontario, this willow had put a single, catkin-laden branch on my path like an offering. I rallied the excuses, succumbed to temptation, and snapped off a piece. It went home in my jacket pocket and soon rooted out in a bucket of water.
This was a nice find. Being a native plant enthusiast and veteran gardener with a penchant for collecting, I’d been on the lookout for a garden-worthy willow. According to Doug Tallamy’s research, willow (genus Salix) is a superstar, supporting 289 species of butterfly as well as 14 species of pollen-specialist bees. Along with oak and cherry, it’s one of the top three species for these aspects of ecosystem function.
Willows are said to be thugs. Yes their roots seek out water, form colonies, and find cracks in underground water and sewer pipes. But given the right site (one with enough space, consistently moist soil, and intact pipes), willows can make excellent home landscape trees. Their early leaf-out, rapid growth, beautiful catkins, and overall resiliency provide spring interest as well as screening and privacy.
My illicit cutting soon became a large shrub that thrived near the downspout in our front yard.
Uncertainty…
Being a plant nerd was no excuse for me to cut from a tree, even an ordinary one, on public land. But having done the nerdy deed, I decided to propagate it at home and give cuttings to my friends—which, in my naive mind, would help atone for my misdeed. But first I needed a species name. There are several species of willow common in this region. Was this really the native pussy willow I thought it was?
How could it not be? Why would anyone plant a tree in this spot, on a steep slope on the Niagara Escarpment, on land that had not been managed since the trail had been a railway line in the 80s? This scraggly shrub looked nothing like the Asian willows popular with landscapers. And only pussy willows bloomed this early in spring. It just had to be Salix discolor.
Keying it out
Having taken a tree identification course at a local college, I was familiar with the dichotomous key, an important scientific tool used to identify organisms based on their observable traits. Dichotomous keys present a set of paired choices that describe various plant characteristics. To identify a plant, one chooses the description that best matches the plant in question. This leads to another pair of choices. The process of making selections, choosing characteristics that best match the mystery plant from a series of paired options, eventually narrows down to an individual species. Grabbing my course textbook (Trees in Canada by John Laird Farrar) I went straight to the “key” section and began sleuthing.
My willow keyed out to Salix discolor, the result I was hoping for. But my delight was tempered by the knowledge of the extreme difficulty of the genus. Walter Muma on Ontario Trees puts it bluntly: “Willows are notoriously difficult to tell apart.” For botanists, even experts and professionals, Salix is a confounding genus—right up there with sedges— in its ability to induce groans and eyeball-rolling among those familiar with its ability to resist being named.
Despite the difficulty I continued to sleuth. Using a second dichotomous key (the one at GoBotany’s Native Plant Trust) I repeated the process and, again, arrived at Salix discolor. I began giving away rooted cuttings with a caveat: “I’m pretty sure this is our native pussy willow Salix discolor, but I’m not 100% certain.”
My handsome, nameless boy
My willow grew, got coppiced, grew back even taller, got cut back again. Perhaps because of my (bad) pruning or the moist site it did not produce suckers. And it was pretty big—a 15-foot bruiser of a shrub four years after planting with two years of unchecked growth. Hanging its branches fetchingly over my neighbour’s driveway, this willow had turned me into one of those bad neighbours people complain about.
Thinking of my aching hips (ladder…), aging arms (pruning saw…), and potential new neighbour (recent funeral and newly unoccupied house…), I began to regret planting the illicit willow. Murderous thoughts crept in. The space would be perfect for my seed-grown steeplebush (Spiraea tomentosa) currently languishing in a four-inch pot. Could I still manage a chain saw? Would the cut-and-cover method work? Would I need a mattock to remove every bit of root?
But how could I dispatch my handsome boy (the catkins were indeed male) without knowing for certain his botanical name? I waffled. The mystery willow lived on.
Then two events spurred me to get a definitive ID. First, a friend asked about the willow cuttings I’d been giving away. Jean, a key volunteer at a native-plant seed orchard, must have been wondering if my willow could be a candidate. The seed orchard had been created by knowledgeable volunteers with expert guidance from the Southern Ontario Seed Strategy, so provenance was important. Not only did the project need full confidence in a species ID, it also needed to know where it had been growing. My old chorus “I’m pretty sure this is a Salix discolor” would not be good enough.
Second, one of the people to whom I’d given a rooted cutting asked about the provenance and identification. Jamie, a fellow native-plant enthusiast, wanted to be absolutely certain it was a native pussy willow. Again, my “pretty sure” was pretty feeble.
I absolutely had to get a definitive ID. My shallow dive into the botanical pond would soon become a deep, murky plunge.
Trying again
So I took another crack at getting a reliable ID. By now, in addition to the interactive key on GoBotany, two more resources had joined my ID arsenal: the classic 1982 reference “Shrubs of Ontario” by James Soper and Margaret Heimburger, long out of print, but available online as a digital flipbook; and a 2006 research paper by the late George W. Argus, former Curator Emeritus of the Canadian Museum of Nature and North America’s leading authority on Salix.
I already had some springtime photos of the catkins. Now I needed some detailed photos of the leaves, bark, and stems, as well as some long shots of the overall form. Thanks to the key on GoBotany and the detailed description in Shrubs of Ontario, I knew which features were important to photograph. For example, does the abaxial (under side) of the leaf have a bloom (white or white-blue waxy or powdery coating), or fine hairs, or a distinct mid-rib? Do the leaf margins have a consistent downward or upward curl? If the leaf margin is not smooth, what is the shape of the teeth: rounded or pointed? How many teeth per centimeter are there? When a cane is cut does the pith have long grooves or is it smooth?
Unfortunately my springtime catkin photos did not clearly show the features I needed most: the hairiness of the filament (the ‘stalk’ that holds the pollen-bearing anther) and the length of the floral bracts.
I made an online photo gallery and invited Jamie to key it out while I did the same. His result was Salix cinerea, an exotic species with an ecological risk rank of five on our regional invasive species list. Not a planet-killer, but certainly not a keeper. Jamie also mentioned Salix bebbiana. My result however was Salix discolor, our native pussy willow. Clearly I needed some expert help—on the plant-ID mission, that is.
Asking the experts
My first email was to Jon Peter, Curator and Manager of Plant Records at the Royal Botanical Garden (RBG) in Burlington Ontario. I’m a volunteer gardener at the RBG so this wasn’t a cold call. Jon looked at my photos and got right back to me with an ID: Salix discolor. I asked Jon about the possibility of it being Salix cinerea or Salix bebbiana and he responded that the RBG has both these species in its collection, and he’s confident it’s the pussy willow.
Wanting to be absolutely sure, I sought a second opinion. I began to wonder if G. W. Argus’s expertise lived on at the Canadian Museum of Nature (CMN). Did Dr. Argus have a successor? I reached out to the CMN in Gatineau, Quebec and was directed to Paul Sokoloff, Senior Research Assistant, Botany. He also promptly looked at my photos and, again, the outcome was S. discolor.
Whew! Both my experts concurred. I declared the mystery solved. My process had not only yielded a reliable ID, but also a valuable learning experience. The help received from the Royal Botanical Garden and the Canadian Museum of Nature made me appreciate the value of these institutions in terms of scientific knowledge. The RBG (a registered charity) and the CMN (a Crown Corporation) were quick to help with a citizen’s request.
Paul Sokoloff at the CMN had been especially generous. After receiving his ID, I subsequently asked him about the fate of an interactive key specifically for North American Salix that used to reside on a server at the Alberta Parks web site. I found an instruction sheet from 2014 but the software was gone. Paul kindly sent me an archived copy of the software and invited me to take it for a test drive. Perhaps some day I’ll be able to get this resource up and running again, keeping Dr. Argus’s work alive and in the public domain for amateurs like me to use.
In the meantime, my purloined willow has continued to escape death. I coppiced it to the ground in 2024 but I didn’t tarp the stump (something Freudian perhaps?) and three months later it was already waist high. Sigh.
Anyone want a pussy willow?