Sunday, October 25, 2020

Those Tiny White Asters

The roadside is full of asters now, a bajillion tiny white flowers transforming insignificant green stems into a feast for bees and butterflies at the end of the season. While most people are content to know that these are asters in the Symphyotrichum genus, a few people like to know which species. I worked through the identification of the four most common ones in my area several years ago.

When it comes to explaining these, I want to borrow some text from Linda Chafin’s Field Guide to the Wildflowers of Georgia, who likens them to the botanists’ version of confusing fall warblers:

No single trait distinguishes any particular species but taking several traits into consideration can usually lead to a sure identification.” See page 120-121 of this very excellent book for more.

Another good resource is the Guide to Vascular Plants of Tennessee (page 449). In general, this resource has the most complete keys for asters and goldenrod (Solidago) that I’ve found so far, although a species or two may be missing for Georgia. The challenging thing about using keys is that the author of the key focuses on a defining characteristic that may not be as apparent to the rest of us (or at least not without dissecting the flower or using a better lens). And be prepared to look up words like ‘phyllary’ which is the green bract underneath the flowerhead; it’s a key concept (literally) in aster identification.

I am a huge fan of roadside native vegetation and am more than happy to stop for a few photos and cuttings to figure out what I’m seeing. When it comes to the roadside white asters, two species seem to be the most abundant and they are known as the “oldfield” white asters. One has noticeably fine hairs on the stem and is called the hairy oldfield white aster or frost aster (Symphyotrichum pilosum) while the other has less noticeable hairs and is called the smooth oldfield aster or small white aster (S. racemosum).

The very floriferous Symphyotrichum racemosum

Symphyotrichum racemosum is my most abundant aster, taking over one bed almost entirely. The spindly limbs permit the sun to reach through to the spring and summer perennials, allowing it to play fairly well with other plants. Come October, those spindly limbs are transformed into arching stems of small white flowers. Not enough resources talk about how the flowers are largely arranged on one side of the stem but this one does; that is something I always look for when identifying this species. Phyllaries are appressed as you can see in the picture below.

Symphyotrichum racemosum bracts
Symphyotrichum pilosum bracts

Symphyotrichum pilosum is distinctive among these four if you can get a look at the phyllaries. These small green structures are not appressed in this species, noticeably reflexed away from the flowerhead. There are visible fine hairs along the stems, sometimes giving it a frosted appearance. This species can vary in size depending on the growing conditions available, reaching up to 4 feet tall and wide when favorable. I love to see it popping up in untended fields; look for it now.

The 'frosted' stems of Symphyotrichum pilosum

Symphyotrichum dumosum is often called long-stalk aster, a name that points to a trait that can be useful in identifying it (the flowers are held away from the stem, on long stalks). With its appressed phyllaries, it most resembles S. racemosum, but the flowers are larger in size and generally there are fewer of them. Long, thin leaves are also useful when identifying it as they can still be present at flowering time.

Symphyotrichum dumosum

Symphyotrichum dumosum bracts
Symphyotrichum dumosum leaves

Symphyotrichum lateriflorum is named for having flowers along one side (lateriflorum), but, as you may recall, there is another species that has that arrangement: S. racemosum. As mentioned in the earlier reference, S. lateriflorum differs from S. racemosum by having wider stem leaves (I think they are darker green too). In addition, the flowers are generally smaller, and the fresh disk flowers are not bright yellow (more straw-colored) and they age to purple compared to a redder color on S. racemosum. S. lateriflorum has the very charming common name of calico aster.

Calico aster, Symphyotrichum lateriflorum

Symphyotrichum lateriflorum bracts

I hope this helps demystify some of the more common species. Here are a few more resources that you might use:

The full set of North American asters at the Astereae lab site (University of Waterloo)

The comparison of phyllary bracts among American asters at

The SERNEC portal for finding and viewing scanned herbarium species. SERNEC is the SouthEast Regional Network of Expertise and Collections

Sunday, October 18, 2020

The Weeds Have It

What do they have? They have what bugs crave! This becomes apparent anytime you get to visit a place where the “weeds” are allowed to flourish. I’m not talking about nasty and non-native weeds like kudzu, privet, and many others. I’m talking about native plants that have been classified by humans as weeds. This past week found me admiring them (and their happy insect friends) along the roads and paths on Jekyll Island.

Gulf fritillary on Bidens alba

Two plants are blooming in abundance now in Coastal Georgia in wild areas: Bidens alba (most commonly known as shepherd's needles, beggarticks, Spanish needles or butterfly needles) and Heterotheca subaxillaris (camphorweed or goldenaster). Several other plants could be found (spotted beebalm, Monarda punctata; spurred butterfly pea, Centrosema virginianum; goldenrods like Solidago sempervirens) but these two really were the dominant roadside/path plants.

“Butterfly needles” seems an apt common name for Bidens alba which was hands-down the favorite of butterflies like the Gulf fritillary, the long-tail skipper (and several other skippers), and more. Last year I saw a Monarch butterfly on it. This rambunctious annual seems to have a limitless capacity for blooming as long as the butterflies need flowers. The needle-like seeds form on old blooms alongside active flowers.

Gulf fritillary on Bidens alba
Long-tail skipper on Bidens alba

The goldenaster (such a nicer name than camphorweed for Heterotheca subaxillaris) was less visited but clearly was being pollinated by something as many flowers were going to seed (sometimes time of day matters for observing insects). This one was especially pretty in mowed edges where it was blooming at much lower heights than on the edges of the sand dunes.

Buckeye on goldenaster
Skipper on goldenaster

In a world where man has developed so much land—paving it over with concrete, asphalt, and lawn—the insects really depend on what’s left of the native plants they need. So when you’re thinking about what to keep and what to 'weed out' in your yard, give the weeds a little consideration and make sure you understand who might benefit from your keeping it.

Goldenaster, Heterotheca subaxillaris

Sunday, October 11, 2020

The Daisy That Isn’t

Helianthus porteri at Arabia
Common names can be delightful (forget-me-not), intriguing (Flyr’s nemesis), and confusing (tulip poplar – neither a tulip nor a poplar!). The plant I want to talk about today goes into the confusing category, in my opinion. The fall-blooming plant with the botanical name Helianthus porteri is a beautiful annual plant that can be found on Georgia’s rock outcrops in prolific numbers every September. This year has been a gorgeous year for it; more on that in a moment. All the common names for this plant contain the word daisy: yellow daisy, Confederate daisy, Stone Mountain daisy. While daisy may be a common name for some flowers in the Asteraceae family, the plant is in the same genus as a sunflower and it irks me to call it a daisy!

Regardless of what we call it, of course, it is a beautiful native plant and one that gives a special grace to Georgia’s granite outcrops each year. This year seemed to be an especially nice year for it and my Facebook feed (lots of plant groups in my feed) was full of gorgeous photos. On September 21, we decided to mask up, pack a lunch, and take the grandkid out to Arabia Mountain to see the beauty (and all the rocks, a big attraction for the little one). Here are some of the photos from our trip.

Helianthus porteri
Will she ever finish taking pictures?

The mixture of rocks and soft flowers is magical!

Blooms might still be out there to see and there are plenty of cool plants to see year-round on outcrops. Follow the organizations that manage the outcrops for alerts next year. Davidson-Arabia Mountain Nature Preserve is a particularly good one on Facebook and Instagram but other places include Stone Mountain Park, Panola Mountain, and Chattahoochee Bend State Park.

Callicarpa americana
Clematis virginiana

Sunday, October 4, 2020

The Jorō Jungle in North Georgia

I don’t usually write about bugs that aren’t pretty butterflies or helpful bees whose interactions with native plants are an important part of the ecosystem. This year is different and hearing about a large uptick in non-native Jorō spiders seemed to fit the theme of 2020; the numbers being reported in Forsyth and Hall counties are scary enough for any Halloween-decorated landscape. I felt like I needed to lend a voice to the story, so I went to visit them at a friend’s house in Forsyth.

The Jorō spider (Nephila clavata or Trichonephila clavata) is a golden orb web weaver spider that is actually related to a native species (Nephila clavipes) which is often called the banana spider. Careful inspection of the markings on the body of the female can determine which species is which. Both create a multi-layered, golden-colored web that can span several feet in width. Typically, the webs are made in open woods or edges of a forest, attached to trees and shrubs. These spiders sometimes live in communal webs that span 8-20 feet, although they can be in single webs that are 3-4 feet across.

The Jorō spider was first discovered in Northeast Georgia near I-85 shipping areas in 2014. I saw my first one when visiting Elachee Nature Center in Gainesville in 2018. Apparently the spiders have been moving outward from the original area, spreading now into surrounding counties like where my friend lives.

Male Jorō

Female Jorō

My friend lives in an established neighborhood with mature shrubs and trees, perfect habitat for these spiders. Over the summer, she began noticing them, jotting down counts of the spiders among all the webs, eventually counting over 70 spiders on her ½ acre lot. She destroyed the ones she could reach, alarmed at how many could be in such a space and concerned about what she might have next year. In walking her dog around the neighborhood and the bigger streets outside the neighborhood, she counted hundreds more. All of these pictures are from those areas. Emails to Georgia experts were met with comments about 'how the populations were certainly increasing' but no real alarm--not a reassuring message when you’re dealing with so many!

Will they continue to spread? It seems likely according to this information from Mattias Johansson, assistant professor of biology at the University of North Georgia Gainesville campus, from a recent article in the Gainesville Times: One thing is for certain, spreading comes naturally to Jorō spiders.Johansson said they use a ballooning technique, in which the spiders spin a web to catch the air current, allowing them to fly for 50-100 miles before latching onto a tree. 

How can we help? First of all, report any identified spiders via iNaturalist either online or using their app. Reports like these give the researchers a big boost in identifying their spread. As of October 3, iNaturalist reports 446 observations (most from Sept 2017 forward) in Georgia. Most are in the NE area around Gainesville and Athens, but this year shows the range expanding south into north Fulton County, west to Dawsonville and Dahlonega, and even one as far as Marietta.

Map of reports from iNaturalist

Second, consider controlling any found in your yard. Invasive organisms aren’t always considered invasive when they are first found; studies of invasive organisms have suggested that a "lag" time is a common feature in their population growth.  Lag times are defined as a period of time between the introduction of an exotic and its period of invasive range expansion. The spotted lanternfly in the Northeastern US was first found in 2014; it is now considered a major pest because of its threat to agricultural crops, a good reason to sound the alarm (pesky exotic spiders might not get such attention until later in the cycle). I’d hate for us to find out too late that this spider’s rapid expansion puts native organisms at risk through competition or excessive prey capture.

Multiple spider nest (arrows show spiders)