Category Archives: Phenology

Smart Weeds

Oriental lady’s thumb is an Asiatic smartweed, Schenley Park, 10 Sep 2021 (photo by Kate St. John)

13 September 2021

Today’s article began with a question asked three times: What is that weed? I couldn’t remember the name even though I knew each was in the knotweed family (Polygonaceae) and that a similar native species was named for Pennsylvania.

On the first question I took a picture in Schenley Park, above. On the second question, Claire Bauerle took a picture at Duff Park, below. My plant and Claire’s plant are both alien but not the same species.

Lady’s thumb (photo by Claire Bauerle)

Claire’s plant shows its name on its leaves, a shadowy thumbprint in the center of the leaf.

Lady’s thumb (Persicaria maculosa) is a Eurasian smartweed that first appeared in the Great Lakes region in 1843, has spread across the continent, and is sometimes invasive. The dark thumbprint is a simple way to identify the plant.

My plant is similar but lacks the thumbprint. Not the same species but my photo is not detailed enough for a complete identification. My guess is Oriental lady’s thumb (Persicaria longiseta) a common weed in Asian rice paddies introduced to North America near Philadelphia in 1910 and now found across eastern North America.

The third question was answered on Sunday’s Botanical Society walk on the South Side where we found the smartweed named for Pennsylvania.

Pinkweed or Pennsylvania smartweed (Persicaria pensylvanica) now grows in waste places around the world. Gangly-looking compared to the lady’s thumbs, it has longer stalks, thinner leaves, and fatter, shorter, paler flower heads.

Pinkweed or Pennsylvania smartweed mixed in with other weeds, 12 Sep 2021 (photo by Kate St. John)

Here’s a single stalk.

Pinkweed or Pennsylvania smartweed, 12 Sep 2021 (photo by Kate St. John)

It has no flower bristles like those found on Oriental lady’s thumb P. maculata.

Flower heads of pinkweed (photo by Kate St. John)

All three smartweeds have stems that connect to the stalks at knot-like ochreas. Two of them, P. longiseta and P. pensylvanicum have bristly ochreas, shown below.

Bristly ochrea on pinkweed, P. pensylvanicum (photo by Kate St. John)

Identifying smartweeds is much trickier than I’ve described so I may have misidentified the first two plants.

If I was smart I’d know what to look for and take better pictures to key them out.

(photos by Kate St. John and Claire Bauerle)

p.s. Three range maps which might not work in Chrome: P. maculosa, P. longiseta, P. pensylvanica

Fall Is Here

Misty walk at Panther Hollow Lake, Schenley Park, 10 Sep 2021 (photo by Kate St. John)

11 September 2021

The weather has been pleasant with low humidity and highs in the 70s. Chilly fall mornings produce a mist on Panther Hollow Lake.

Asters are blooming right on time …

Asters (photo by Kate St. John)

… but this hawthorn tree is confused, opening two flowers and a leaf in September.

Hawthorn tree puts out two flowers and a leaf, Schenley Park, 10 September 2021 (photo by Kate St. John)

This eastern screech-owl confirms it’s fall when he peeks from his well known roost on 4 September. Though screech-owls breed in Schenley Park, they only use this roost during the non-breeding season.

Eastern screech-owl at the winter roost, Schenley Park, 4 Sep 2021 (photo by Kate St. John)

My least favorite hot weather will return tomorrow through Tuesday, forewarned by this morning’s red sunrise.

Red sky at morn, sailors forewarn.

Sunrise in Oakland, Pittsburgh, 11 Sep 2021 (photo by Kate St. John)

(photos by Kate St. John)

Late July Flowers and Seeds

Oxeye or false sunflower, Nine Mile Run Trail, 29 July 2021 (photo by Kate St. John)

31 July 2021

In late July field flowers bloom while others develop seeds.

The photo at top of oxeye or false sunflowers (Heliopsis helianthoides) was supposed to be a documentation photo so I could study the leaves. Can you find the milkweed bug on one of the flowers?

Blue vervain (Verbena hastata) is blooming at Presque Isle State Park where I took this photo on Wednesday. Vervain flowers are so small that the plant looks boring from afar. It is well worth a closer look.

Blue Vervain, Presque Isle State Park, 28 July 2021

On Thursday Charity Kheshgi and I explored the grassland top of the slag heap at Nine Mile Run. In one area the slag is so porous that rainwater percolates straight though it, creating a desert habitat. Nonetheless we found a vibrant orange butterfly weed (Asclepias tuberosa) in bloom.

Butterfly weed at the slag heap, 29 July 2021 (photo by Kate St. John)

Namesake plant: Dwarf St. John’s wort (Hypericum mutilum) is native to North America.

Dwarf St. John’s wort, Moraine State Park, 30 July 2021 (photo by Kate St. John)

Seeds! Redbud trees (Cercis canadensis) in the city parks have a bumper crop of seed pods this year.

Redbud seed pods, thick on the branches, Nine Mile Run Trail, 29 July 2021 (photo by Kate St. John)

Nodding thistle (Carduus nutans) has gone to seed along the lower Nine Mile Run Trail where it looked like this in June (click here). We saw many American goldfinches feeding on these natural thistle feeders.

Nodding thistle seeds, Nine Mile Run Trail, 29 July 2021 (photo by Kate St. John)

Today is our last chance to enjoy July. The weather is lovely in Pittsburgh so get outdoors.

(photos by Kate St. John)

Blooming This Week in July

Nodding onion (Allium cernuum) at Phipps fence, 19 July 2021 (photo by Kate St. John)

24 July 2021

The weather came out of the northwest bringing cooler temperatures on Tuesday and Wednesday and smoke from the Canadian wildfires more than 1,000 miles away. Even when the air quality was bad this week I went outdoors. Perhaps I was fooled that it was OK since it didn’t have that sulfur smell typical of Pittsburgh pollution.

This week I went further afield than Schenley Park. Here are highlights from Frick, Schenley, Aspinwall Riverfront Park and Moraine State Park. The captions tell the story.

Horse nettle (Solanum carolinense), Frick Park, 20 July 2021 (photo by Kate St. John)
Black Snakeroot (Actaea racemosa or Cimicifuga racimosa) at Moraine State Park, 22 July 2021 (photo by Kate St. John)

Common mullein (Verbascum thapsus) has small flowers that we rarely see up close because they bloom on a six foot spike.

Common mullein inflorescence, Aspinwall Riverfront Park, 21 July 2021 (photo by Kate St. John)

We definitely notice the spike. And then the rest of the plant.

Common mullein, Aspinwall Riverfront Park, 21 July 2021 (photo by Kate St. John)

Meanwhile, my namesake plant is still blooming. This one was at Moraine State Park.

St. John’s wort (Hypericum sp.), Moraine State Park, 22 July 2021 (photo by Kate St. John)

(photos by Kate St. John)

Future Summers Will Last Half The Year

Hot summer sun (photo from Wikimedia Commons)

20 July 2021

Withering heat, parching drought, devastating floods, dangerous wildfires.

As unpleasant as this summer has been in the Northern Hemisphere we comfort ourselves that better weather will arrive with autumn in September. But even that is changing. A new study published in Geophysical Research Letters predicts that by the end of this century winter, spring and fall will retreat while summer will last nearly half the year.

For perspective on the future the researchers studied the past across the Northern Hemisphere, specifically the length of seasons from 1952 to 2011. They set the parameters for summer as the “onset of temperatures in the hottest 25% during that time period, while winter began with temperatures in the coldest 25%.” Spring and fall filled the gaps.

During those sixty years, summers got longer while the other seasons shrank. The slides below show the historical seasons 1952 and 2011 plus the study’s prediction for the year 2100. By then summer will run from May to October.

Average seasonal lengths in Northern Hemisphere, information from

For those of you who don’t like winter this sounds like a great idea but the reality will be unsettling. The long summers and short winters will continue to have extreme temperature and precipitation swings with stunning storms like those we’ve seen in recent years. Imagine the heat of July lasting three months or more.

Meanwhile pleasant days will become scarce. My favorite seasons, spring and fall, will be shorter.

Our great-grandchildren will live in a very different world.

Read more and see the large version of this animation at Northern hemisphere summers may last nearly half the year by 2100 at

(photo from Wikimedia Commons, simple pie charts by Kate St. John, embedded animation from

Photos From a Humid Week

Peppergrass, Duck Hollow, 3 July 2021 (photo by Kate St. John)

10 July 2021

Pittsburgh’s weather fluctuated this week from pleasant to oppressively humid. Always late to get outdoors, I missed the best part of each day. The flowers were open but the birds were hiding at:

  • Duck Hollow and Lower Nine Mile Run on 3 July. 73 degrees, a pleasant day!
  • Montour Trail on 5 July. 85 degrees in the shade, cooler in Enlow Tunnel.
  • Three Rivers Heritage Trail on the South Side on 6 July. Almost 90 degrees and very sunny.
Echinacea, Lower Nine Mile Run Trail, 3 July 2021 (photo by Kate St. John)
Tall meadowrue, Montour Trail, 5 July 2021 (photo by Kate St. John)
Fringed loosestrife, Montour Trail, 5 July 2021 (photo by Kate St. John)
White avens, Lower Nine Mile Run Trail, 3 July 2021 (photo by Kate St. John)
Bush honeysuckle fruit, Lower Nine Mile Run Trail, 3 July 2021 (photo by Kate St. John)

I was dripping with sweat on 6 July when I found this namesake plant, St. John’s wort (Hypericum prolificum), pushing up from a crack in the sidewalk. What a hardy plant standing tall on a hot day. I wilted after 30 minutes in the sun.

St. Johnswort pushing up from a crack in the sidewalk, South Side Pittsburgh, 6 July 2021 (photo by Kate St. John)

p.s. A story about peppergrass.

(photos by Kate St. John)

Milkweed and Scissor-Grinders

Swamp milkweed with carpenter bee, yellow jacket, and pearl crescent butterfly (photo by Kate St. John)

1 July 2021

July is the month for bugs and field flowers and late nesting birds — for milkweed and scissor-grinder cicadas.

Among the milkweeds my favorite is swamp milkweed (Asclepias incarnata) for its vibrant pink color and more delicate leaves. Insects like it, too.

July is also when the first scissor-grinder cicadas (Neotibicen pruinosus) appear (in my neighborhood, first heard on 3 July 2021). Their whirring drone is said to resemble the sound of scissors being ground or sharpened, but who among us has heard that manufacturing sound? Scissor-grinders are more common than the sound they were named for.

Scissor-grinder annual cicada, Pittsburgh PA, (photo by Kate St. John)

Lots more is on tap for the month of July. Check out the list in this vintage article: Milkweed or What to Look for in July.

(photos by Kate St. John)

Becoming Summer

Yellow Goat’s Beard flower and seed pod, 11 June 2021, Moraine State Park (photo by Kate St. John)

12 June 2021

Temperatures have fluctuated widely in the past couple of weeks — from chilly damp to searing heat — but the plants and insects keep on their steady march to summer.

Above, yellow goat’s beard (Tragopogon dubius) now has both flowers and seeds.

Below, this sprig of bedstraw (Galium sp) has almost finished blooming with just one flower and many seeds. The plant feels sticky because its stems, leaves, and seed pods are all covered in tiny hooked bristles that act like Velcro.

Bedstraw gone to seed, 11 June 2021, Moraine State Park (photo by Kate St. John)

In Schenley Park the tulip trees (Liriodendron tulipifera) have finished blooming, the “tulips” are fading and dropping their petals.

Tuliptree flower is fading, 8 June 2021, Schenley Park (photo by Kate St. John)

As birdsong wanes the bugs are taking over the soundscape. I’ve already heard the first crickets and an unknown-to-me insect that buzzes at 5,000 hertz in Schenley Park.

And who is this? None of us could name him yesterday at Moraine State Park. Can you identify this hunched insect with bright orange antenna tips? If so, please leave a comment.

UPDATE: This insect is a leaf-footed bug, probably Acanthocephalus terminalis, thanks to Kim’s comment.

Who is this? Insect at Moraine State Park, 11 June 2021 (photo by Kate St. John)
Who is this? Insect at Moraine State Park, 11 June 2021 (photo by Kate St. John)

(photos by Kate St. John)

Rhododenrons: Wild and Tame

Rhododendron in the wild at Ferncliff Peninsula, PA, 1 July 2015 (photo by Kate St. John)

30 May 2021

In Pennsylvania we plant azaleas and rhododendrons in our gardens but we can also find them in the wild. I am reminded of this in late May when the cultivated rhododendrons and wild azaleas bloom.

At the garden store azalea bushes are short dense shrubs that bloom in April, while rhododendrons are tall woody shrubs that bloom in late May. Scientifically they are all Rhododendrons with minor differences. The big difference for me is that the garden plants bloom four to six weeks before the wild ones.

Yesterday I found flowering rhododendrons on Pitt’s campus. Some were white (below) like their wild progenitors shown at top in Fayette County.

Cultivated rhododendron at Univ of Pittsburgh, white, 29 May 2021 (photo by Kate St. John)

Others were hybridized to create purple flowers.

Cultivated rhododendron at Univ of Pittsburgh, purple, 29 May 2021 (photo by Kate St. John)

To see the wild ones I visit the Laurel Highlands around the Fourth of July, especially Ferncliff Peninsula at Ohiopyle State Park. Nowadays it pays to go a little earlier than the Fourth because climate change has moved things up.

Meanwhile last weekend at Moraine State Park Karyn Delaney found wild azalea in bloom.

Wild azalea at Moraine State Park, 22 May 2021 (photo by Karyn Delaney)

Sometimes wild azaleas (Rhododenron periclymenoides) are called “pinkster” in southwestern Pennsylvania but it’s not because the flower is pink. They were named “pinxter” for the Dutch word for Pentecost because wild azaleas bloom at that time of year.

This year Pentecost was 23 May. Wild azalea is blooming right on time.

(photos by Kate St. John and Karyn Delaney)

p.s. What’s the difference between an azalea and a rhododendron? Not much. They have slightly different leaves and azalea flowers usually have 5 stamens while other rhododendrons have 10.

Frick Park on the Cusp of May

  • Barred owl, Frick Park, 2 May 2021 (photo by Charity Kheshgi)

2 May 2021

Frick Park and adjacent Duck Hollow are two of the hottest birding hotspots in southwestern Pennsylvania. So many birds show up during spring migration that we birders spend hours there in April and May.

Frick’s 644 forested acres are a green oasis halfway through Pittsburgh’s developed metro area. The Monongahela River at Duck Hollow beacons to water and shorebirds while the woods attract songbirds to refuel before continuing north.

screenshot of Pittsburgh, PA regional map,

The Pittsburgh Parks Conservancy map of Frick Park shows how Duck Hollow (furthest point south) connects to the larger park. The birding is so good in that corridor that I often walk from Duck to Frick. If the two locations were a single hotspot their combined species count would probably surpass 200. Click here to download the Frick Park map.

screenshot of Frick Park map from Pittsburgh Parks Conservancy. Click here to download the map

Charity Kheshgi photographs birds at Frick Park and/or Duck Hollow nearly every day. Her slideshow above includes a few of the birds she saw on the cusp of May. See more by following her on Instagram at

p.s. I was there for the Blackburnian warbler but missed the barred owl because I didn’t visit Frick on 2 May. So many birds, so little time!

(photos by Charity Kheshgi, maps from Google and Pittsburgh Parks Conservancy)