Late fall is the perfect time of year to look for alien plants in Pennsylvania.  Natives are brown or leafless but alien species are still cuing on the seasons back home.

How do you find aliens?  Notice patches of green in the brown landscape.  Here are three photos to give you some practice.

Aliens in the top photo are circled below.

See aliens while you’re driving …

See aliens on the ground …

There’s so much goutweed and garlic mustard in this last photo that it would be filled with red circles if I labeled all of it.   🙁

(photos by Kate St. John)

In July these green and yellow flower spikes tower along our roadsides and waste places.

Common mullein (Verbascum thapsus) is a Eurasian native of the figwort family (Scrophulariaceae) that was introduced to North America.  Because it’s biennial both forms are visible right now.

In its first year of life, the plant is a basal rosette of velvety blue-green leaves, 4-16 inches long.

In its second year the rosette sprouts a flower spike, blooms in the summer, sets seed, and then dies.

Here it is in the spring of its second year. The basal rosette is beginning to flower.

And here’s a closeup of the flowers:

Though common mullein only reproduces by seed it’s very good at doing it.  Each plant produces 100,000 to 180,000 seeds that are dispersed by wind or animals.  If the seeds don’t land in a hospitable place, no problem.  They’re viable for 100 years!

Consequently, common mullein is listed as invasive in 20 states including Pennsylvania, Ohio and West Virginia.

Because it only spreads by seed, this plant can be eradicated by hand pulling before the seed sets, then bagging it and disposing of it.  Unfortunately, it’s too late in the season to do that now and other methods, such as poison, will only spread its seeds when the plant falls.

We’ll just have to enjoy its flowers and wait until next year.

When it comes to weeds, I love procrastinating!

(photos by Kate St.John)

Last week Anne Marie Bosnyak sent me a photo, below, of a plant that popped up in her garden.

It has purple flowers and tomato-like fruit. It’s obviously growing in the wrong place.  Is it a weed?

Well, yes.

It’s bittersweet nightshade (Solanum dulcamara), a perennial from Eurasia that’s considered invasive in Pennsylvania.

Did you know it’s related to potatoes?  Don’t eat it!  Read on.

Not Tomatoes

(flower photo by Chuck Tague, plant photo by Anne Marie Bosnyak)

23 May 2017

In late May, you’ll see white fluff in the air as you search the sky for birds.  It’s not dandelion fluff.  This is cottonwood season.

The eastern cottonwood (Populus deltoides) grows in open and riparian habitats from the Rockies to the southeastern coast. Western Pennsylvania is on the eastern edge of their range.

Cottonwoods are one of the fastest growing and largest trees in North America.  Reaching up to 130 feet tall the trunk can be more than five feet across.  The trees require bare soil and full sun to germinate so you usually see them out in the open, sometimes alone.

Their species name, deltoides, describes the leaf shape that looks a lot like aspens. Both trees are in the willow family.

In early spring cottonwoods sprout male and female catkins. The females are fertilized by wind-blown pollen and become drooping strings of seed capsules.  In May the capsules burst open to release thousands of tiny seeds, each one attached to a bit of “cotton” that carries it on the wind.  (The brown spots in this photo are seed capsule covers, not the seeds.)

The fluff breaks off and blows away but each tree is so prolific that in windless conditions, when the fluff falls straight to the ground, it looks like snow.

Do you want to see a lot of cottonwood fluff?  Drive north on Route 528 from the bridge over Moraine State Park‘s Lake Arthur. Eventually cottonwoods are on both sides of the road.

There’s fluff in the air there!

(photo credits:
fluff on the ground by Chris Evans, University of Illinois, Bugwood.org
range map from Wikimedia Commons; click on the image to see the original
clump of cottonwood trees by Steven Katovich, USDA Forest Service, Bugwood.org
cottonwood leaves by T. Davis Sydnor, The Ohio State University, Bugwood.org
cottonwood seeds on the branch by Troy Evans, Great Smoky Mountains National Park, Bugwood.org)

Jack in the Pulpit (Arisaema triphyllum) has been blooming for about two weeks in western Pennsylvania.  As the forest floor greens up you might not notice this unusual flower.

Click below for a whimsical look at Jack’s odd characteristics.  Sometimes he is “Jill.”

Jack Explains Himself