Author: Priscilla Hollingsworth

Southern Naiad: another native plant

Southern Naiad: another native plant

By Priscilla Hollingsworth

I was leaning over the boardwalk last week, and I spotted a plant in the main Butler Creek stream that I had not seen there before. Clearly it was attached to the bottom and had long, wavy green stalks and leaves that rippled in the current. It’s really kind of pretty. I was wondering, what is this plant?

Southern Naiad in flowing water

Various Phinizy Center staff helped me figure it out.  I showed photos on my camera to Aaliyah Ross and Jen McGruter in Education, and they began flipping through books in their library.  Jen grabbed a D-net, and we went back to the boardwalk, where she used the net to fish out some of the plant.

Southern Naiad close-up

You can see it has long, slender stems and very skinny leaves.  The leaves on the tips of the stalks round out into spatulate forms.  Jen really had to tug to get some of the plant to break away from the bottom, so it is pretty strongly rooted.

Southern Naiad branching habit

Jen examined the branching structure of the leaves.  Here, the leaves appear to branch off in pairs along a given stem.

Then we trekked over to the Research building, and asked Nate Hobbs what he thought.  He directed us back to a very small book in the Education office, where we found an entry on Southern Naiad, or Najas guadalupensis, which is a native species to our area.  Ruth Mead came in just then and confirmed we had found the right plant.

I felt like I had taken up too much of everyone’s time, but Jen assured me that this had been useful – now they had an identification on another native plant found right in Phinizy Swamp.

Here’s what I learned about Southern Naiad.  It’s found over most of North and South America, in fresh waterways such as lakes, ponds, streams, and canals.  The plant can grow up to about 10 feet long – it may need to if the waterway is that deep, since it’s rooted to the bottom and the leaves need to reach the sunlight near the surface for photosynthesis.  There are about 40 naiad species worldwide.  The leaves are quite narrow and grow in opposite pairs or in whorls of three.  The leaves have little teeth shapes on the margins, but you will need magnification to see the teeth on some varieties of the plant.  You’ll also need magnification to see the flowers – they are tiny.

Southern Naiad is an annual.  It spreads easily by seed or by bits of the plant breaking off and rooting elsewhere.  In some situations, it is considered a weed because it grows so fast and can take over the space in a pond or stream.  However, you can’t argue that it’s taken over at the Phinizy Swamp boardwalk – it’s clearly not overabundant relative to everything else growing nearby.  Southern Naiad is a primary food for turtles and waterfowl.  Macroinvertebrates (tiny water animals that are just large enough to see with the naked eye) find shelter in this plant.

Finally, the way the long green strands ripple in the water kind of reminded me of mermaid hair.  That’s a good association with the plant’s name.  Naiads were female water spirits in ancient Greek mythology.

Things to see at the swamp right now: more signs of spring

by Priscilla Hollingsworth

It seems like the more I look at the swamp, the more there is to see. These are things I noticed during the past week.

swamp trees

A week or two ago, everything seemed to be that gray-brown color of winter in the swamp.  But here you see some grasses growing.  And there is a little flash of red in the trees in the background – this is because the Red Maple tree has lots of red seeds to show.


red maple seeds

Another view of the Red Maple seeds that are so dramatic right now.  Red Maple is also called Swamp Maple – how appropriate – and its Latin name is Acer rubrum.  Some people call the seeds “helicopters” because of the way they twirl in the air when they fall to the ground.  Interestingly, Red Maple is both flood- and drought-tolerant.


red maple seeds in closeup

And here’s a closeup showing the shapes of the seeds with their winglike structures.


greening under trees

Here’s an area under trees that has greened up quickly.  The little green plants are almost all non-grass types that grow very quickly.


sea myrtle greening

The Sea Myrtle is showing small green leaves.  Sea Myrtle, or Baccharis halimifolia, has spread inland in our area – it originally was native to the coast.  It is a wetland plant.


cypress trees getting leaves

The Bald Cypress trees are getting their leaves again – you can see the rusty-colored leaf growth coming in at the tops of the trees right now.  Bald Cypress, or Taxodium distichum, is called “bald” because it loses its leaves in the winter.


6cypress leaves 2

Another view of a cypress tree getting its leaves out.


spanish moss in the rain

Spanish Moss (Tillandsia usneoides) with raindrops clinging to it.  Okay, not so much a sign of spring!  But I couldn’t resist the photo, and walking in the rain when it’s not that cold any longer can be fun.


wolf spider

This was a rather large spider that I encountered on the walk outside the Visitors Center.  What do you think about spiders?  This one was about an inch long, and I observed it carefully while not getting too close.  Looking it up, it seems most likely to be a Wolf Spider, possibly a Hogna helluo or Hogna carolinensis.  Wolf spiders are a large category, so perhaps it is better just to say this one is probably in family Lycosidae.  Wolf spiders often love wetlands and wet forest areas.  Most wolf spiders are active at night, so I don’t know why this one was out in the daytime.  They can bite people, but are not likely to unless people poke at them over and over again (moral: leave the spider alone, and it will leave you alone).


Carolina jasmine buds

You’ve probably seen this plant – it’s Carolina Jasmine, or Gelsemium sempervirens.  Carolina Jasmine is a native plant, and many people encourage it in their yards when it appears spontaneously.  But at the swamp, you get a chance to see it in its natural state.  The photo above shows yellow buds almost ready to open.


Carolina jasmine in bloom

And here, some of the flower buds are open.


wild Bradford pear invasive in bloom

Finally, I promised earlier to post a photo of a Bradford pear tree-turned wild, in bloom.  It’s really pretty, isn’t it?  But sad that these suburban self-hybriding escapees are becoming so invasive in our landscapes locally.


Bradford pear invasive hybrids blooming

Above is a photo of escaping/proliferating Bradford pear descendants along Doug Barnard Parkway, on the way to the swamp.  Take a look as you drive along this and other major roads in Augusta.  In situations where road crews trim back highway growth about once a year, you will see these trees proliferating savagely.  Cutting them back about once a year is the best way to make them spread all the faster.  I don’t know what the solution is – I think that has still to be discovered.

The Dead of Winter – but Signs of Spring are Showing

The Dead of Winter – but Signs of Spring are Showing
By: Priscilla Hollingsworth

I was walking in the nature park a couple of days ago, on a chilly, depressingly gray day. At this time of year, grays and dull browns predominate in the landscape at the Phinizy Swamp:

winter view towards Butler Creek

view towards Butler Creek

But it turns out there is still plenty to see.  For one thing, if you look up at the tops of some of the trees, you can see the swelling of growth that will pop out into leaves in a few weeks:

Tree swelling for spring

Trees swelling for spring

The effect is still subtle, but the smallest branches of the trees just look thicker than a couple of weeks ago.

And I saw a couple of plants up close that are budding:



And this one, which I am pretty sure is one of those trees that I wrote about recently, the Bradford pear/Callery pear wild hybrids that are rampaging through our landscape:

"Frankenpear" - wild Bradford pear/Callery pear hybrid, with buds

“Frankenpear” – wild Bradford pear/Callery pear hybrid, with buds

This tree will be so pretty when the blooms come out, I will probably take another photo.

I saw some other interesting things on my walk.  Here’s a view of hairy poison ivy vines, in their winter state, but very much full of life and able to blister the skin of anyone who tries to pet their hairiness:

Hairy poison ivy vines on trees

Hairy poison ivy vines on trees

Here’s what looks like a mud ball, hanging from a dangling branch:

Mud ball

Mud ball

Could it be a mud dauber’s nest?  I wasn’t able to identify it.

Note on 2/10: Aaliyah Ross, Environmental Educator at the Phinizy Center, advises that this strange-looking ball is probably a gall.  Thanks, Aaliyah!  I looked up galls, and they are growths on trees that can be caused by a variety of organisms foreign to the host tree, such as insects, fungi, bacteria, nematodes, and even other plants!  Sometimes the gall is harmful to the host plant, and sometimes not.

Winter is a great time for being able to see into the woods.  You can see structures that later will be covered over with green growth:

Small tree trunk twisted by a vine

Small tree trunk twisted by a vine

The vine that caused the young tree to swell and twist is still embedded in the trunk.

And finally, here is some really interesting-looking swamp water, as viewed right off the School Bus bridge:

Red patch and slime in the water

Red patch and slime in the water

I wish I could identify what is happening here.  My own research didn’t yield any real information.  At the lower left in the photo above, you can see a red growth or substance.  And in the middle, the water has interestingly thick and slimy-looking areas.

Note on 2/10:  Aaliyah Ross advises that the red substance is mosquito fern.  Mosquito fern, genus Azolla, is a tiny plant that grows rapidly on the surface of water that is not moving fast.  It can be red or green, at different times of the year, responding to temperature and sunlight changes.   Mosquito fern has some interesting qualities and can be a beneficial part of an ecosystem – or when there is too much fertilizer runoff into a wetland, it can grow too much and become invasive.  As for the slime in the water on the right, Aaliyah says this is the result of some kind of bacterial action, in which bacteria are decomposing plant matter.   Personally, I think slime is fascinating, and I look forward to learning more about it.

Even a dull winter day at the swamp yields some interesting sights.

-Priscilla Hollingsworth

Too smart for our own good: the Callery Pear and the Bradford Pear

I have been looking at these amazingly thorny young trees that are growing on some of the berms (levees/roadways) that run between the ponds of the constructed wetlands. What amazing texture – and what horrible thorns. It would be hard to imagine pushing my way through a thicket of these.

Callery pear hybrid web

Frankenstein meets the Bradford pear tree

Ruth Mead (Senior Environmental Educator at the Phinizy Center) pointed out to me that these thorny trees are related to Bradford pear trees. You know Bradford pear trees – they are everywhere, in parking lots and suburban yards. For a long time, these were considered perfect landscaping trees: they grow fast, they are oblivious to poor growing conditions, and they are pretty most of the year (flowers in the spring, glossy green leaves in summer, dramatic leaf colors in the fall). Later on, people started recognizing that mature Bradford pear trees crack and break limbs easily because of the growth pattern of their branch structure. But other than that, this seemed like an ideal, easy tree to grow in yards and on city streets. Many people still love and grow them.

It turns out that the truth is much more complex than that. Remember the promise of kudzu? It was supposed to be this great, fast-growing plant that controls erosion on steep hillsides in the South. It was imported from Asia. We all know that kudzu turned out to be a disaster, the green monster that Eats The South. In other words, kudzu is a poster child for the concept of an invasive species. How did a good thing become a bad thing? Sometimes human decisions go wrong.

Callery pear closer web

“Franken-Bradford” closer up

Bradford pear trees were developed in the U.S. as a variant of Pyrus Calleryana, or Callery pear trees. Seeds from Callery pear trees were brought from China beginning around 1918 as part of a possible solution to a pear tree disease that was devastating American pear fruit crops. The Callery pear tree is highly resistant to various diseases, and it grows well in a variety of environmental conditions. Over decades of experimentation and research, botanical scientists in the U.S. developed cultivars of this plant with promising qualities. The most famous cultivar was the one named Bradford. And for decades, Bradford pear trees were planted seemingly everywhere, with few problems. A useful feature of the Bradford pear was that it seemed to be NOT invasive – it was basically sterile. Bradford pear trees produce lots of pretty flowers, but usually no fruit or seeds. What’s not to love about that? If you need another tree, you can buy them at all the major garden centers, because horticultural businesses can make more trees through grafting and other methods.

However, scientists did not stop experimenting with the Callery pear tree when they discovered the Bradford cultivar in the 1960s. In the decades since then, more variants have been brought onto the market – pear trees with various desirable qualities that are a little different from the Bradford. Within the last ten years, there has been a sudden explosion of spontaneously appearing trees like the one in my photo. Many of these unwanted Callery pear trees grow extremely rapidly and have very tightly arranged branches studded with long thorns. They appear in thick stands at the edges of cleared land, along fence lines, and along roadways. Cutting the trees down makes them grow even faster and thicker from the roots. They are resistant to diseases, too painful for deer to munch on because of the thorns, and they crowd out the plants that would naturally grow in these spots. Yow! I think I could write a horror movie script about these trees. How did this situation come to pass?

Callery pear closest web


It turns out that, for specific genetic reasons, Callery pear varieties are often sterile in terms of being able to pollinate themselves or other trees of the same variety. So, a tree that is sterile isn’t going to become invasive, right? But as more varieties came on the market, the different varieties were sterile in relation to their own kind – but often fertile when pollinated by a slightly different variety. And the different varieties back-crossed with each other, often bringing out extremely undesirable qualities (such as lots of thorns) in trees that then grow freely in locations that are not mowed regularly. Another kudzu-monster has been born. And did you know that the southern U.S. is on the same latitude as the part of China where the original Callery pear tree is native and grows most easily? American Callery pear hybrids will be that much harder to eradicate in our region because of this.

So was there ever a point when reasonable scientists, administrators, government officials, etc. could have reasonably suspected that their efforts to improve American pear trees might take a dark turn? And what do we do now about our invasion of self-hybridizing Asian pear tree descendants?

For further history of the science involved with Callery pear research, this is a good article:

-Priscilla Hollingsworth

Raccoon spotted!

While walking in the swamp recently, a raccoon ran across my path. It quickly climbed high into a tree, and stayed there, looking down at me.

I’m familiar with raccoons in my backyard, raccoons in alleys, raccoons getting into the trash.  But I wondered, what’s it like to be a a wild raccoon living at the Phinizy Swamp?

raccoon in tree

raccoon in tree

The most interesting thing about raccoons to me is how adaptable they are. They are quite smart and are good at learning how to work new situations to their advantage. Their Latin name is Procyon lotor, which more or less means “doglike animal that washes a lot” (they are actually a little more closely related to bears than dogs). They are native to forests and waterways all over North America, though they may well have originated in the Southeast. So you could say that this raccoon that I saw is in its most native habitat – in a forest/wetlands area in Georgia.

raccoon closeup

raccoon closeup

Raccoons are omnivores, and they do their best to get a varied diet. In the swamp, they are probably eating plant parts such as nuts and fruits, eggs from birds’ nests, worms and crustaceans and other invertebrates from soil and water areas, smaller vertebrates, and even carrion. In other words, they sample widely from everything available to them in a forest/wetland habitat.

The “washing” behavior isn’t fully understood. It may be somewhat instinctive and derived from the raccoon’s origins as a hunter along waterways. The raccoon’s skin on its forepaws is extremely sensitive, and seems to become more so when it is moistened.

A raccoon’s rear paws are also special. Unlike a cat’s, a raccoon’s back paws can rotate backwards as the animal descends a tree – so the raccoon that I saw could as easily run down the tree trunk as it ran up. Wild raccoons tend to sleep and nest in trees.

In really cold winter weather, raccoons can go into a state called “winter rest”. It’s not hibernation – their heart rate drops, but their body temperature stays normal. If the weather warms up, a raccoon can quickly come out of winter rest and get moving again.

A raccoon in the wild lives for two to three years, usually. In captivity, raccoons live a more catlike lifespan. Most wild raccoons are killed by disease or by getting run over by an automobile when they cross a road. The natural predators for the raccoon I saw would be bobcats, coyotes, and the larger birds of prey.

Finally, raccoons are most active at night, but it isn’t that unusual to see them during the day. They are just so adaptable in their behaviors that almost any rule you could cite about them has exceptions.

-Priscilla Hollingsworth

Iridescent Swamp Water

iridescent scene adjusted sm
I was walking on the boardwalk at Phinizy Swamp the other day (near the Visitor Center), and I noticed water with a reflective, fascinating iridescence.

Why is there iridescence on the surface of the water under the boardwalk? Is this pollution?

So I did some reading. The answer is no, this is supposed to be a natural phenomenon and NOT evidence of spilled oil. It’s true that an oil spill can create a pretty rainbow of color in a thin layer across the surface of a natural body of water. But this effect can also be created by a natural swamp process, and that is what seems to be happening here.

iridescence 3 sm
Kelsey Laymon explained the iron reduction process in wetland soils in a recent Research Blog post:

Because the soil under the water surface stays wet most of the time, there is very little oxygen in it. This means that most of the biological processes that are most familiar to us, the ones that use oxygen, just aren’t happening. Instead, special bacteria that use non-oxygen processes (anaerobic) are at work. Some of these bacteria live by reducing iron that occurs naturally in the soil from one form to another, and the iridescence you are seeing is a result of those processes. The very thin, iridescent film on the surface of the water is a form of iron.

iridescence 1 sm
In a review of internet resources, not all knowledgeable people tend to agree about whether a given patch of iridescence in swamp water is due to iron bacteria interacting with iron compounds, or is an actual petroleum spill. After all, swamps have been used as waste dumps. If the iridescent layer is thick and tarry, and certainly if it smells like petroleum – it probably is.

One quick field test sometimes suggested for determining whether an iridescent layer on water is from iron bacteria or petroleum is to stir it a bit with a stick. If the surface sheen gloms back together smoothly, it’s petroleum. If it breaks into jagged-edged shapes, it’s a natural iron-breakdown phenomenon caused by iron bacteria. Here’s a blowup of the photo above (taken right off the Phinizy Swamp boardwalk), and you can see there are jagged edges on the iridescent film:

iridescence 1 closeup sm
And here’s another photo:

iridescence 4 sm
Iron bacteria contamination happens a lot to people with wells in areas where the soil has a high iron content. We think of it as contamination because iron bacteria working in an enclosed area produce some really unpleasant smells. They can create slime that clogs plumbing, and often a bright orange form of iron precipitate that stains porcelain. Have you encountered this? You don’t want it in your plumbing, but in the swamp, it’s a valuable kind of natural anaerobic process.

-Priscilla Hollingsworth