Archive for the 'Plants' Category

Sep 06 2015

Master Asters

Published by under Books & Events,Plants

Asters (photo by Kate St. John)

Asters (photo by Kate St. John)

September is the month for asters and goldenrods but these plants are so hard to identify that I usually say: “It’s an aster (or goldenrod) but I don’t know which one.”

Now there’s hope for the aster-onomically challenged.  Pennsylvania Botany is offering a one-day seminar on identifying asters and goldenrods on September 22 at Nescopek State Park.  Participants will use keys and floras and get plenty of hands-on practice.

Master asters at this seminar.  It’s open to the public but is not free.  See the links below for more information.

Aster and Goldenrod Identification Workshop
September 22, 2015 • 9:00 a.m. – 5:00 p.m.
Nescopeck State Park, Environmental Education Center
1137 Honey Hole Road • Drums, Pennsylvania 18222
Directions/information on Nescopek State Park.


(photo by Kate St. John)

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Aug 31 2015

Bees Can’t See Red

Honey bee at camas (photo from Wikimedia Commons)

Honey bee at camas flower (photo from Wikimedia Commons)

When I wrote about hummingbirds and orange jewelweed last week, some of you wondered if the birds sipped at pale (yellow) jewelweed, too.  While finding the answer I learned a cool fact:  Bees can’t see red.

Hummingbirds are attracted to shades of red so they see the spots on orange jewelweed (Impatiens capensis) as a delicious target and rely on this plant during fall migration.

Over time the spur on Impatiens capensis has evolved to maximize pollination by hummingbirds with a tight cone-shaped entrance that guides the birds’ bills.

Spotted jewelweed, Impatiens capensis (photo from Flora Pittsburghensis)

Orange jewelweed, Impatiens capensis (photo from Flora Pittsburghensis)

Hummingbirds don’t care about yellow so they don’t choose the other jewelweed — the “pale” one — but bees do.

Bees see yellow, purple, blue, and a color called bee’s purple, a mixture of yellow and ultraviolet which we humans can’t see.  Bees can’t see red so they aren’t much attracted to orange jewelweed.

However, pale jewelweed (Impatiens pallida) is designed for bees.  Not only is it yellow but its expandable entrance accommodates both large and small bees, brushing their bodies as they walk in.

Pale jewelweed, Impatiens pallida (photo from Flora Pittsburghensis)

Pale jewelweed, Impatiens pallida, with a bee inside (photo from Flora Pittsburghensis)

Though the two jewelweeds grow near each other, they send different signals.  Red is for birds.  Yellow is for bees.


(Honey bee photo from Wikimedia Commons. Orange and pale jewelweed photos by Flora Pittsburghensis.  Click on the images to see the originals)

p.s. On the subject of bees (in general) here’s a recent article from The Allegheny Front about breeding stronger honey bees:  Building a Better Honeybee

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Aug 30 2015

Showy Food For Birds

Published by under Plants

American spikenard fruit at Schenley Park, August 2015 (photo by Kate St. John)

American spikenard fruit at Schenley Park, 20 August 2015 (photo by Kate St. John)

Here’s a native perennial that produces lots of fruit for migrating birds.

American spikenard (Aralia racemosa) is a showy plant that grows three to five feet tall and wide.  It blooms in airy greenish-white spikes from June to August and ripens its fruit in August and September, just in time for migrating birds. Click here to see it in bloom.

American spikenard, Schenley Park, August 2015 (photo by Kate St. John)

American spikenard, Schenley Park, 20 August 2015 (photo by Kate St. John)

In my opinion, the plant was misnamed. People must have hoped it was similar to the real spikenard, Nardostachys jatamansi, a Himalayan plant in the Valerian family whose root is made into fragrant essential oil (called nard), but American spikenard is not at all like it and isn’t even in the same family. The American plant isn’t valuable to humans; it cannot make perfume.

But Aralia racemosa is valuable to birds. It’s a low maintenance plant that likes full sun or partial shade and spreads slowly by seeds and rhizomes.  In August it offers showy fruit for birds.

Click here for more information at the Missouri Botanical Garden.



(photos by Kate St. John)

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Aug 29 2015


Published by under Plants

Boneset in bud (photo by Kate St. John)

Boneset in bud, July 2015 (photo by Kate St. John)

In the field guides Boneset’s leaves are described as perfoliate. Its scientific name says it too: (Eupatorium perfoliatum).

The word comes from Latin.

Per means “through”

Foliate, from folium, means “leaf”

Through the leaf.


(photo by Kate St. John)

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Aug 19 2015

It Grows a Mile a Minute

Published by under Plants

Mile-a-minute weed (photo by Kate St. John)

Mile-a-minute weed (photo by Kate St. John)

If you ever see this plant, eradicate it!

My first encounter with Mile-a-minute weed was a decade ago in the Laurel Highlands when a small patch of leaves caught my eye.  Such perfect triangles! I didn’t know the plant but if I had I would have uprooted it.

Mile-a-minute weed (Persicaria perfoliata) is an annual, trailing vine, that thrives in sunlight and can grow 6 inches a day(!).  It has triangular leaves and perfoliate cups at the stem joints, called ocreae, where it produces flowers and fruit.  (Click here to see the fruit.)  Notice the recurved thorns on the stems and on the underside of the leaf veins that give it this alternate name: Devil’s tear-thumb.

Mile-a-minute stem (photo by Kate St. John)

Mile-a-minute stem (photo by Kate St. John)

Persicaria perfoliata tried to invade North America several times but didn’t take hold until the late 1930s when it charmed a nurseryman in York County, Pennsylvania. He received it unintentionally in a shipment of seeds, was fascinated and allowed it to grow. By the time he realized his mistake it was too late.  Birds and animals love the fruit and spread the plant.  Mile-a-minute now swamps southern Pennsylvania, Maryland, and parts of the Mid-Atlantic and New England.  It has spread more than 300 miles since it left York.  Click here for the map.

If you think you’ve found Mile-a-minute weed, check a few things before you pull.  Does it have perfect-triangle leaves?  Does it have thorns?  If so, you’ve found the bad stuff.  Does it have fruit?  Put on your long pants, long sleeves and gloves and pull — and try not to spread the fruit!

I found this fruitless specimen dying in Frick Park last weekend.  I had noticed it in July and was finally returning to pull it but, thankfully, park stewards had already dosed the area with therapeutic defoliant.  Good!  I administered the final blow and pulled it out.


(photos by Kate St. John)

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Aug 16 2015

Now Blooming: Biennial Gaura

Published by under Phenology,Plants

Biennial gaura (photo by Kate St. John)

Biennial gaura, closeup (photo by Kate St. John)

Though the plant looks like a tall weed, this pretty flower is blooming now in fields and open areas.

As its name suggest, Biennial gaura (Gaura biennis) takes two years to bloom.  In the first year it’s a rosette of basal leaves that sends down deep roots to survive wet winters and dry summers.  In the second year it grows 4-6 feet tall and blooms in August.

The flowers are white when they bloom and turn pink as they fade.  I never notice the plant until the flowers are pink.


(photo by Kate St. John)

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Aug 15 2015

Sneezes Coming Up

Published by under Plants

Giant ragweed closeup (photo by Kate St. John)

Giant ragweed closeup (photo by Kate St. John)

These yellow capsules are closed but soon they’ll burst open and fling their pollen to the wind.

Last Wednesday I found this giant ragweed (Ambrosia trifida) growing along Nine Mile Run Trail south of Commercial Street.  The plant is so tall that the flower spike is at eye — or should I say nose — level.  Fortunately it’s not as tall as the record-setting 21-foot specimen in Texas.

Giant ragweed flower spikes (photo by Kate St. John)

Giant ragweed flower spikes, 12 August 2015, Pittsburgh (photo by Kate St. John)

Though the flowers aren’t open yet ragweed season officially begins today, August 15.  Hang on to your handkerchiefs!

Learn more here about ragweed and how to identify the ‘common’ one.


(photos by Kate St. John)

UPDATE August 16:  The capsules have opened.  The pollen is out.   Ahhhh-choo!

Giant ragweed and its pollen, 16 August 2015 (photo by Kate St. John)

Giant ragweed and its pollen, 16 August 2015 (photo by Kate St. John)

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Aug 09 2015

Green Head

Published by under Plants

Green-headed coneflower (photo by Kate St. John)

Green-headed coneflower (photo by Kate St. John)

Green-headed coneflower (Rudbeckia laciniata) is blooming now in western Pennsylvania.

Look for its green head and swept-back yellow petals in open woods and fields.


(photo by Kate St. John)

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Aug 07 2015

Deadly Beauty

Published by under Plants

Datura flower (photo by Donna Memon)

Datura flower (photo by Donna Memon)

This night-blooming flower grows like a weed in Arizona.  Here, Donna Memon captured a trumpet glowing in the setting sun.

Datura grows easily in the Arizona desert and is cultivated around the world.  There are currently nine species, many of which are hard to identify because the plant changes its characteristics to suit the growing conditions.  Its common names include jimsonweed, moonflower and angel’s trumpets.

Though beautiful it is extremely poisonous, producing hallucinations, elevated body temperature, tachycardia, severe pupil dilation, unconsciousness and death.  Thus it was surprising to me that it’s called “sacred datura” in Arizona because Navajo and Havasupai shamans used low doses for religious hallucinations.

The proper dose is hard to determine and if you get it wrong you die.  The correct amount varies — even in the same plant — based on age, soil conditions and local weather.  Despite the warnings people try it and, as Wikipedia says, “Few substances have received as many severely negative recreational experience reports as has Datura. The overwhelming majority of those who describe their use of Datura find their experiences extremely unpleasant both mentally and often physically dangerous.”

The angel’s trumpet is beautiful but a deadly way to see angels.

Read more here at Wikipedia.

Datura flowers (photo by Donna Memon)

Datura flower and bud (photo by Donna Memon)


(photos by Donna Memon)

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Jul 26 2015


Published by under Plants

Galinsoga or Quickweed, flower closeup (photo by Kate St.John)

Galinsoga or Quickweed, flower closeup (photo by Kate St.John)

This flower is blooming everywhere right now but we never notice it.  Its beauty is tiny and the plant is a weed so we pass it by.

Galinsoga or Quickweed is an annual in the Aster family with small daisy-like flowers with five notched petals.  The leaves are opposite and toothed in a jumbled mass below the long, branching flower stems that give the plant a messy “leggy” appearance, 6-18 inches high.

Look closely and you’ll see the leaves and stems are both hairy.  But no one looks closely unless they want to eat it (yes it’s edible).

Here’s what we typically see when walk past Galinsoga on the street.

Galinsoga flowers (photo by Kate St. John)

A patch of Quickweed by the street (photo by Kate St. John)

Once you start looking, Quickweed is everywhere: growing in the sidewalk cracks, sprouting in gardens, covering an abandoned lot where its density makes it pretty.  Local gardeners call it “Pittsburgh Pest.”

It earned the name Quickweed or Raceweed because it produces seed rapidly (7,500 seeds per plant per year) and has many generations in the same season.

When it’s gone to seed it looks like this.

Galinsoga gone to seed (photo by Kate St. John)

Galinsoga gone to seed (photo by Kate St. John)

The genus is Galinsoga but what is the species?

Good question!  My Newcomb’s Wildflower Guide lists only Galinsoga ciliata = Galinsoga quadriradiata.  Richard Nugent and Flora Pittsburghensis both identify it as Galinsoga parvifloraQuadriradiata is from Mexico, parviflora is from South America.  In any case, it didn’t jump an ocean to find us.

But it jumped an ocean to Europe.  Galinsoga parviflora was taken from Peru to Kew Gardens in 1796 where it escaped to the wild and quickly became a weed.

Aha!  Quickweed.


(photos by Kate St.John)

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