Category Archives: Plants

plants & fungi

Invasive Lesser Celandine

Lesser celandine at Duck Hollow, 23 April 2019 (photo by Kate St. John)

29 March 2023

This is the time of year when invasive plants sprout and bloom before the natives, particularly lesser celandine (Ficaria verna), a member of the Buttercup family with succulent leaves and bright yellow 8-12 petal flowers.

According to, lesser celandine prefers sandy soil in low open woods, floodplains, meadows and waste places. It spreads easily through tubers and tiny bulblets so a scouring flood or digging in its vicinity, including digging animals, spreads it to new sites. It also thrives because it’s poisonous and deer don’t eat it.

I usually find lesser celandine blanketing floodplains including those at the Monongahela River at Duck Hollow — where it’s already in bloom — and Chartiers Creek at Boyce Mayview and Wingfield Pines.

Lesser celandine at Boyce Mayview, 15 April 2015 (photo by Kate St. John)

Blanketing is what makes it invasive. Native spring ephemeral flowers need unobstructed sunlight to complete their life cycle but lesser celandine leafs out early, blankets the ground and shades the natives before they can make a start.

When I was learning to identify plants I used to confuse it with the native plant marsh marigold (Caltha palustris).

Lesser celandine (left), Marsh marigold (right, photo from Wikimedia Commons)

Penn State Extension explains the difference between them here but the biggest hint is this: If the plant is carpeting the ground and blooming in March or early April, especially on a floodplain, you can bet it’s lesser celandine.

p.s. Learn more about invasive plants in Pennsylvania at DCNR’s Invasive Plant Fact Sheets at

(photos by Kate St. John and from Wikimedia Commons)

In Ecuador, A Tale of Two Flowers

Nasa grandiflora at Yanacocha, Ecuador, 30 Jan 2023 (photo by Kate St. John)

12 March 2023

While on the trail in Ecuador at Yanacocha Reserve on 31 Jan 2023, this beautiful native flower attracted my attention. Nasa grandiflora, is a member of the Loasaceae family and endemic to the mountains of Peru, Ecuador, and Columbia.

Nasa grandiflora at Yanacocha, Ecuador, 30 Jan 2023 (photo by Kate St. John)

I could not resist looking inside the flower bell so I tipped it up and took two photos, one focused at the opening, the other focused deep inside.

Nasa grandiflora at Yanacocha, Ecuador, 30 Jan 2023 (photo by Kate St. John)
Nasa grandiflora at Yanacocha, Ecuador, 30 Jan 2023 (photo by Kate St. John)

Most people don’t touch this plant but I didn’t notice its black spines, including on the sepals (see photo below) that act like stinging nettle when you touch them. It’s a good thing it was so cold that I was wearing gloves.

The second flower that caught my attention was along the back roads in the Mindo area and was hard to miss. Its vines draped over everything at the sunlit openings.

Black-eyed susan vine (Thunbergia alata) is native to eastern Africa but is grown in gardens in many countries. In tropical areas it has become invasive including in Ecuador and Florida.

Black-eyed susan vine, Thunbergia alata. Seen every day in Ecuador (photo by Kate St. John)

Once this vine takes hold it is difficult to eradicate because it grows fast above ground and spreads rapidly via rhizomes. It was sad to see the Ecuadoran equivalent of porcelain berry or kudzu.

Vigorous growth of Thunbergia alata (photo from Wikimedia Commons)

Gardeners don’t realize what they’ve wrought until it’s too late. Here are some examples from the invasives section of

Invasive Thunbergia alta (photo by Forest and Kim Starr, Starr Environmental,
Invasive Thunbergia alta (photo by Forest and Kim Starr, Starr Environmental,

The two flowers have different survival strategies: The native flower has a spiny defense. The alien overcomes the competition.

(photos by Kate St. John and from, click on bugwood captions to see the originals)

Spring On Pause + Spring Forward

Crocus in Shadyside garden, Pittsburgh, 9 March 2023 (photo by Kate St. John)

11 March 2023

After a very warm February, with some days reaching 20° to 26°F above normal, the weather returned to expected March temperatures this week and our Too Early Spring hit the Pause Button.

The city’s Urban Heat Island still prompted non-native ornamental plants to bloom including crocuses above and forsythia below.

Forsythia in bloom, 4 March 2023 (photo by Kate St. John)

Garlic mustard came up in Schenley Park.

Garlic mustard, 5 March 2023 (photo by Kate St. John)

Native trees, like this sycamore in Schenley Park, waited for warmer weather while non-native willows turned yellow such as the willows at bottom right (perhaps Salix babylonica).

A shadow of the Panther Hollow Bridge bisects this view of a sycamore in Schenley Park (photo by Kate St. John)

But there are better things to look at. Last Sunday the Botanical Society visited the Otto and Magdelen Ackerman Reserve in Westmoreland County where we found yellow corydalis (Corydalis flavula) poking up among the fallen leaves. No flowers yet.

Leaves of yellow corydalis, Ackerman Reserve, 4 March 2023 (photo by Kate St. John)

Plus two impressive fungi on fallen trees.

Armallaria formerly hidden under bark, Ackerman Reserve, 4 March 2023 (photo by Kate St. John)
Are these turkey tails? Ackerman Reserve, 4 March 2023 (photo by Kate St. John)

By the way, don’t forget that Daylight Saving Time begins tonight in most of the U.S. It’s time to Spring Forward.

(photos by Kate St. John, .gif from Wikimedia Commons)

Too Early Spring: Snow Trillium

9 March 2023

On Monday 6 March 2023, Fran Bungert sent me an email to say that she saw snow trillium blooming at Cedar Creek Park the day before. She added that 5 March is the earliest she’s ever seen it bloom.

In my experience snow trillium (Trillium nivale) is usually the earliest spring ephemeral in southwestern Pennsylvania, traditionally blooming in late March or early April. The flowers persist for about four weeks so my observations circled below are not necessarily first bloom date. Nonetheless Fran’s 5 March observation in red is the earliest ever!

Snow trillium observed blooming at Cedar Creek, Kate St. John’s selected years 2000-2023 (calendar image from

Inspired to see the flowers I visited Cedar Creek on Tuesday afternoon. Before I reached the snow trillium hillside, I found evidence of flash floods that cut the creek bank. It was a brown landscape compared to what I see in April.

Cedar Creek and streamside trail, 7 March 2023 (photo by Kate St. John)

Snow trillium dotted the hillside but blended into the fallen leaves because the white flowers looked like splashes of sunshine. How many flowers do you see in this photo?

The flowers were at various stages from barely to fully open, at top.

Snow trillium at Cedar Creek, 7 March 2023 (photo by Kate St. John)

I found harbinger of spring (Erigenia bulbosa) leaves but no flowers.

As of 7 March only the snow trillium was blooming at Cedar Creek.

(photos by Kate St. John)

p.s. For my own notes, here’s a list of blogs that indicate when I saw snow trillium:

Wildflowers Threatened by Too Early Spring

Large-flowered Trillium, Barking Slopes, blooming on 25 March 2012 (photo by Kate St. John)

8 March 2023

North American wildflowers face many threats to their existence including habitat loss, deer overpopulation and pollinator declines but there is another threat we didn’t see coming until now. As the climate heats up North American spring ephemerals will have no time to bloom and store food for the coming summer. Their existence is threatened by the Too Early Springs of climate change.

Forest wildflowers bloom before the trees leaf out because they are in a race to gather as much sunshine as possible before the canopy closes. When the trees reach Full Leaf the flowers stop blooming.

Wildflowers in deciduous forests often rely on leafing out before the canopy to create 50-100% of their annual carbon budget. Lead author and Carnegie Museum of Natural History postdoctoral research associate Dr. Benjamin Lee describes it “as if a person were to eat all the calories they needed for a year in the first three weeks.” 

Climate Change Threatens North American Wildflowers

Ideally, wildflowers would merely advance their blooming schedules and all would be well but the study published last December in Nature Communications shows otherwise. Using herbarium specimens in North America, Europe and Asia, researchers compared wildflower blooming times and tree leaf out dates for the three continents.

Blooming early works in Europe and Asia because those trees leaf out later anyway. But in North America the trees and flowers use the same temperature trigger. We had a real life example of this in Pittsburgh in March 2012 when temperatures stayed in the 60s to 70s for at least two weeks. In that Too Early Spring everything happened at once.

I visited Barking Slopes on 25 March 2012 and I found both early and late spring wildflowers in bloom: Bloodroot (Sanguinaria canadensis) which normally blooms in late March or early April and large-flowered bellwort (Uvularia grandiflora) which normally blooms in late April.

Bloodroot and bellwort both blooming at Barking Slopes, 25 March 2012 (photos by Kate St. John)

The trees were leafing out, too.

Leaf out on 25 March 2012 at Barking Slopes (photo by Kate St. John)

June weather in March? What could go wrong?

Fewer spring wildflowers in the future.

Read more about the Too Early Spring of 2012 below. Will it happen this year? Only time will tell.

(photos by Kate St. John, diagram from Wildflower phenological escape differs by continent and spring temperature)

p.s. The time gap between bloom-time and leaf out is called the “wildflower phenological escape” hence the study’s name.

How Early Is Spring This Year?

Honeysuckle leaf out 23 days apart, 2015 vs 2023 (photo by Kate St. John)

6 March 2023

This winter has been so warm in Pittsburgh that flowers bloomed and plants leafed out in February. Spring is early, but how early?

Some years I photograph bush honeysuckle’s early leaves and I can tell you that leaf out this spring is 23 days earlier than in 2015. But that’s only one year.

The USA National Phenology Network ( tracks the progress of Spring using two indicators, bush honeysuckle and lilac leaf out and blooming times, and then compares them to the average in 1991-2020. The Spring Leaf Index Anomaly map for 4 March 2023 shows that this spring is astonishingly early.

Spring leaf out anomaly (honeysuckle), 4 March 2023 (map from

The darkest red indicates 20+ days ahead of schedule. USAnpn called out a few examples in their 27 February report:

[As of 27 February 2023] Oklahoma City, OK is 9 days early, St. Louis, MO is 16 days early, and New York City is 32 days early. Phoenix, AZ is a week late. Seattle, WA is a week early.

USA National Phenology Network — Status of Spring, 27 Feb 2023

How often does this anomaly happen? The darkest green on the map below shows that this is the earliest spring ever recorded in New York City while purple indicates the latest spring ever seen in southeastern Arizona.

Spring Leaf Index Return Interval, 5 March 2023 (map from

Arizona might be even later now. Here’s snow in Tucson last Thursday morning just after dawn.

Snow in Ramona Sahni’s Tucson backyard just after dawn on 2 March 2023 (photo by Ramona Sahni)

Click here to watch an animated map of spring’s advance through 4 March 2023.

(photos by Kate St. John and Ramona Sahni, maps from

Seen This Week

Flowering cherry, Pittsburgh, 1 March 2023 (photo by Kate St. John)

4 March 2023

This week the weather stayed above freezing with an extraordinary high of 72F on 1 March. The plants and trees responded by bursting into bloom and leaf. Pictured here are:

  • A flowering cherry tree in Shadyside, 1 March
  • Coltsfoot in bloom at Moraine State Park, 1 March
  • Hairy bittercress blooming in Shadyside, 2 March
  • London plane tree seed balls disintegrating (a spring thing), 27 Feb
  • Honeysuckle leaf out, 2 March.

A week ago my photos of blooms, buds and leaves were 4 weeks earlier than last year. When I get a chance I’ll see if spring is still running four weeks ahead of schedule.

Coltsfoot blooming, Moraine State Park, 1 March 2023 (photo by Kate St. John)
Hairy bittercress blooming, 2 March 2023 (photo by Kate St. John)
London plane tree seed ball disintegrating, 27 Feb 2023 (photo by Kate St. John)
Honeysuckle leafing out, 2 March 2023 (photo by Kate St. John)

Now that the plants are waking up for spring Pittsburgh’s deer (over)population is finding more to eat. In front of Phipps’ Botany Hall I found a side-by-side example of yews, a favorite deer winter food, protected and unprotected from deer browse. One bush has no protection, the rest were wrapped in plastic fencing(*). You can already see the difference.

(photos by Kate St. John)

(*) The protected yews were wrapped on 15 December 2022 so, at the time of the photo, the unprotected yew was showing 10.5 weeks of deer browsing.

More Noxious Weeds

Winged burning bush (photo by James H. Miller, USDA Forest Service via

28 February 2023

Last month the Pennsylvania Department of Agriculture added two more landscape plants to the list of Pennsylvania Noxious Weeds: Winged burning bush (Euonymus alatus) and privet hedge (Ligustrum spp.). They jumped the queue into Class B Noxious Weeds because they are widely established in the wild with no hope of getting rid of them.

Winged burning bush (Euonymus alatus):

Native to China, Japan and Korea winged burning bush is a very popular landscaping plant that is so good at growing in dense shade that it invaded Pennsylvania’s woods. You’ve seen it in your neighborhood in October when the leaves turn bright red or magenta.

Winged burning bush in a parking lot (photo by Leslie J. Mehrhoff, University of Connecticut via
Winged burning bush (photo by Leslie J. Mehrhoff, University of Connecticut via

Right now it is leafless but you can recognize it by the flanges or “wings” on the stems. Here’s what it looks like in summer with opposite leaves on the stem.

Winged burning bush in summer (Chris Evans, University of Illinois via

It’s not as pretty when it escapes to the wild.

Euonymus escaped to the wild (photo by Richard Gardner,

By January 2025 it will be illegal to sell winged burning bush in PA nurseries and garden centers. Meanwhile you’re encouraged to replace it with native species, listed here.

Privet hedge (Ligustrum spp.)

Privet hedge (Ligustrum amurense) (photo by Richard Webb via

Almost everyone knows what a privet hedge is. Privet is the hedge that makes you buy hedge clippers and use them frequently.

Last month the Pennsylvania Department of Agriculture declared four species of privet noxious in PA: border privet (Ligustrum obtusifolium), common privet (L. vulgare), Japanese privet (L. japonicum), and Chinese privet (L. sinense). But no Ligustrum is native to the U.S. so if you see privet it’s an alien.

Glossy privet leaves (photo by John Ruter, University of Georgia via

Privet’s ability to bounce back from cutting and regenerate from its roots make it great for borders but tenacious in the wild. I remember how hard it was to get rid of it from the border of my yard. It kept coming back until I dug up the roots.

Privet in the wild is not orderly, not tame at all.

Privet in the wild in the U.S. (photo by John D. Byrd, Mississippi State University,

Just as for winged burning bush, privet will be banned from sale at PA nurseries and garden centers in January 2025. Meanwhile, save yourself time with the hedge trimmers. Dig up those privet roots and plant a native shrub. Substitutes listed here.

(photos from credited in the captions; click on the captions to see the originals)

Seen This Week

Woodland crocus or Tommasini’s croscus, 21 Feb 2023 (photo by Kate St. John)

25 February 2023

For seven days this week the temperature stayed above freezing and hit 71 degrees F on Thursday. At 26 degrees above normal, flowers opened on plants and trees.


My favorites were the early crocuses. Native to Bulgaria, Hungary, Albania and the former Yugoslavia, these woodland crocuses (Crocus tommasinianus) are often seen in gardens but someone in my neighborhood planted them in a grassy front yard. Because the flowers bloom before the grass grows they are in no danger of being mowed.

Tomasini’s crocuses blooming in the grass, Neville Ave, 21 Feb 2023 (photo by Kate St. John)

On Pitt’s campus Cornelian cherry trees (Cornus mas) produced yellow flowers.

Flowers of Cornelian Cherry, 20 Feb 2023 (photo by Kate St. John)

Red maples (Acer rubrum) bloomed next to Carnegie Museum …

Red maple flowers near Carnegie Museum, 20 Feb 2023 (photo by Kate St. John)

… and at Frick Park the maple branches looked thick with tiny flowers, including yellowish pollen-bearing ones.

Maple trees against a blue sky. Branches look thick with small flowers and pollen anthers, Frick Park, 23 Feb 2023 (photo by Kate St. John)

This week, tiny leaves opened on jetbead (Rhodotypos scandens) and a few honeysuckle bushes. Unfortunately invasive plants are first to leaf out.

New leaves opening on jetbead, Frick Park, 23 Feb 2023 (photo by Kate St. John)

The coming week will be like a wet blanket: above freezing, gusty wind, lots of rain.

(photos by Kate St. John)

Not the Same: Yucca, Yuca

Yucca and yuca (photos from Wikimedia Commons)

20 February 2023

In Ecuador I ate yuca, not yucca. The names sound the same and are nearly spelled the same but they are not the same plant at all.

Yuccas are members of the asparagus family (Asparagaceae) that grow in hot, dry places in the Americas and Caribbean. Ranging from ground-based rosettes of sword-shaped evergreen leaves to the Joshua tree (Yucca brevifolia) of the Mojave Desert only their flower petals are eaten and then only in Central America. The yucca’s main cultivated use is as an ornamental plant.

Joshua tree (Yucca brevifolia) (photo from Wikimedia Commons)

But back in the 1700s when Europeans were renaming everything they found in the Americas, “early reports of the [Yucca] species were confused with cassava (Manihot esculenta). Consequently, Linnaeus mistakenly derived the generic name for yucca from the Taíno word for the cassava, yuca.” — quoted from Wikipedia yucca account

It’s hard to imagine how the mix up occurred. Their leaves and growing patterns are not at all the same.

Cassava or yuca leaves (photo from Wikimedia Commons)

Yuca, also called cassava, manioc and Manihot esculenta, is a native woody shrub of South America whose tuberous roots are a food staple in the tropics around the world. Yuca was already a local mainstay food when Europeans arrived to analyze it. Today it is “a primary component of the diet of more than 800 million people around the world.”

Cassava tubers (photo from Wikimedia Commons)

The taste ranges from sweet to bitter but the roots contain cyanide so they must be peeled, soaked and boiled or else cut or ground and sun-dried before eating.

After the root is prepared for eating it can be made into flour, tapioca, chips, noodles, fries etc. I ate fried yuca in Ecuador. It tastes like French fries.

Fried yuca (photo from Wikimedia Commons)

Mmmm good!

(photos from Wikimedia Commons; click on the captions to see the originals)