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Phenology Report, May 17th 2022

Spring azure butterfly
Photo by iNaturalist user kenkneidel
Spring azure butterfly

It's been a busy week for John! When he looked at his notes, he had observed over 120 unique phenological events over the last seven days, including these species:

  • Trees: Trembling aspens, birches, box elders, bur oaks, chokecherries, cottonwoods, crabapples, horse chestnuts, ironwoods, red maples, red oaks, mountain ashes, silver maples, and weeping willows.
  • Shrubs: American hazels, beaked hazels, blueberries, fly honeysuckles, juneberries, leather leafs, leatherwoods, mountain maples, nannyberries, pagoda dogwoods, red osier dogwoods, round leaf dogwoods, pin cherries, prickly gooseberries, raspberries, blackberries, smooth roses, and speckled alders.
  • Flowers: Canada columbines, several varieties of sedges, blue flags, common tansies, cup plants, dandelions, dwarf raspberries, horsetails (including field, meadow, and forest horsetails), Jack-in-the-pulpits, lady ferns, ostrich ferns, interrupted ferns, bracken ferns, large-leafed asters, cowslips, large-flowered trilliums, nodding trilliums, Pennsylvania sedge, woodrush, hepatica, trailing arbutus, sessile-leaf bellworts, vetches, starflowers, (he runs out of breath at this point, then continues), white violets, and wood anemones.
  • Insects and animals: Goldfinches, redstarts, orioles, hummingbirds, June bugs, juncos, ospreys, ovenbirds, trumpeter swans, yellow warblers, rose-breasted grosbeaks, spring azure butterflies, green darner dragonflies, wood ticks, and deer ticks.
  • Frogs and toads: Wood frogs, spring peepers, chorus frogs, tree frogs, northern leopard frogs, and American toads.

Whew! What a list! Momma Nature has kept John hopping this week, that's for sure.

I hope he had time to celebrate- his beloved trembling aspens finally leafed out on May 13th! They narrowly missed the record for the latest leaf-out John ever observed: May 17th in 2014 (the earliest was on April 2nd, 2012). John then describes a little flower, about 5-6 inches tall, with a pale yellow flower hanging down: the sessile-leaf bellwort. It belongs to the genus Uvularia, which comes from the same origin as "uvula," the dangly bit at the back of your mouth. John quipped, "I'd touch mine right now, but then I wouldn't be able to speak very clearly!" The sessile-leaf bellwort bloomed on May 16th: its average is May 12th, with the latest flowering on May 22nd in 2013 and the earliest flowering on April 26th in 2010. John also notes that the trailing arbutus bloomed on May 16th (the average blooming date is May 5th).

If you're driving or hiking around this week, John recommends you watch the Juneberries. They leafed out almost two weeks late, so no blooms yet: however, John expects them to flower this week. Look for inch-wide, white flowers that bloom simultaneously- the whole tree flowers at once! Individual trees may bloom on different days, but all the flowers on a single tree will open on the same day.

Juneberries can be confused with the American or Canada plum: they both have white flowers and bloom around the same time. John's tip to distinguish the two from a distance is to examine how many grow together: plums grow in thickets, while Juneberries will only have 1-10 stems in a single location. So, if you see a dense group of white-flowered shrubs stretching on for several yards, you've found some plums! If you can get up close to look at the flowers, it's easier to distinguish the two species. The plum flowers have wide, oval petals, while the juneberries' petals are elongated and thinner. In addition, the bark of the juneberry is smooth and grey, while the plum has shaggy bark. Go take a look and see if you can tell them apart!

After dabbling in shrubs, John goes back to his favorites: the aspens. They're a great demonstration of the rushed seasonal changes that have kept John hopping all week: everything is happening at once! In a typical year, the trembling aspens would bloom around April 30th, and the big-toothed aspens would bloom around May 20th: a three-week gap. In years like we're experiencing, where cold April weather has delayed the onset of spring, the gap shrinks! In 2013, the gap between events shrunk down to a mere seven days. This year, John expects the big-toothed aspens to leaf out 9-15 days after the trembling aspens. Since the trembling aspens leafed out on May 13th, that would suggest the big-toothed aspens should be putting out leaves sometime between May 20th-24th! They are well on their way, having already flowered and discarded their male catkins. When they do leaf out, you can distinguish the two species of aspens by looking at the color of their leaves. When they first develop, big-toothed aspen leaves are a very pale, almost sage-green color. On the other hand, trembling aspens are much more vibrantly colored: John describes them as grape-green, yellow-green, or bright green in color.

While the aspens are greening up, there's plenty of action going on in the understory. John recommends looking for our native fly honeysuckle, the Canada fly honeysuckle. Its leaves emerge early, and it will have twin yellow flowers: look for a 4-5 foot tall shrub with large green leaves and paired sets of trumpet-shaped yellow flowers. It is opposite branched (the twigs on each side emerge side by side), not alternate branched (the twigs emerge in a staggered pattern- see image below). It isn't just a pretty plant: the Canada fly honeysuckle is also an important source of nectar for many insects, including bumblebees, paper wasps, and the spring butterflies (including mourning cloaks, Compton tortoiseshells, and the comma butterflies).

Illustration of alternate and opposite branching patterns
Image from "Botany for young people and common schools", 1868. Slightly modified.
Illustration of alternate and opposite branching patterns

Speaking of butterflies, John tells us that there's "A new butterfly on the scene!" It's less than an inch across, with wings that are bright blue on top and gray underneath, and it is called the spring azure butterfly. These butterflies (or one of them, at least) emerged from their chrysalises on Thursday of last week, about a week later than scheduled. Good news for the butterflies: there are no cranky bosses in nature to complain about the time clock! There's just John Latimer meandering through his forest and greeting each new arrival with joy. The spring azures are the first butterfly to emerge from a chrysalis in spring- the other early-season butterflies overwinter as adults. (John includes a sidenote here- "A chrysalis is a cocoon except that when there's a butterfly inside, it's a chrysalis. If there's a moth inside, it's a cocoon.")

While the spring azure butterflies were taking their first test flights last week, John was out being a social butterfly! At a birthday party for his friend, he talked with a woman who loves chokecherries but has difficulty identifying them. Luckily, John was there with the expert tips: now is the perfect time to identify chokecherries! Their leaves are just beginning to emerge, showing a markedly reddish color (John describes the leaves as a bronzey-green). The shrub itself has dark grey bark with little whitish openings. It's also distinguished from other shrubs by a particular type of fungus which grows on its bark: black knot fungus. John characterizes it as a fungus that causes a growth on the stem that looks like "dog excrement was wrapped around the stem of the branch." Despite its less-than-appealing looks, black knot fungus is a handy signpost to help you identify chokecherries- see if you can find it!

John ends the broadcast with this: "There's a lot of stuff going on out there. The world is changing as we speak! If you are thinking about phenology, this is a perfect time of year to get out and start identifying a few plants in your yard and writing down what they're doing. And by golly, next year, you'll have that data with you! You'll know whether the next spring is earlier or later than the present one." I agree: so let's get out there and see what we can find! Until next week, happy exploring!

I've included a bonus clip because everyone deserves a laugh mixed with their nature news! The extra clip starts at 15 minutes 34 seconds. It contains some banter between Heidi and John, phenology project updates, and a fun story about John's dog and a skunk. Check it out!

As a mail carrier in rural Grand Rapids, Minn., for 35 years, John Latimer put his own stamp on a career that delivered more than letters. Indeed, while driving the hundred-mile round-trip daily route, he passed the time by observing and recording seasonal changes in nature, learning everything he could about the area’s weather, plants and animals, and becoming the go-to guy who could answer customers’ questions about what they were seeing in the environment.
Heidi Holtan is KAXE's Director of Content and Public Affairs where she manages producers and is the local host of Morning Edition from NPR. Heidi is a regional correspondent for WDSE/WRPT's Duluth Public Television’s Almanac North.
Charlie Mitchell (she/they) joined the KAXE team in February of 2022. Charlie creates the Season Watch Newsletter, writes segment summaries for the website, and coordinates our Engaging Minnesotans with Phenology project. With a background in wildlife biology, she enjoys learning a little bit about everything, whether it's plants, mushrooms, aquatic invertebrates, or the short-tailed shrew (did you know they can echolocate?).