Invasive Autumn Fern

 

Many of us have come to gardening already knowing the big invasive plants in Georgia: kudzu, privet (Ligustrum), mimosa (Albizia julibrissin), tree of heaven (Ailanthus altissima), English ivy (Hedera helix), chinaberry (Melia azedarach), and more. Some plants, however, are joining that list (or moving up in priority) even as gardeners plant them. Autumn fern (Dryopteris erythrosora) is one of those plants that people need to know about. Unfortunately, it doesn’t even seem to have made the list but it is listed in a publication called New Invaders of the Southeast (p.24).

Autumn fern in creek

A couple years ago I had a young autumn fern show up in my yard. It was right in the front shade bed, mixed among the native ferns. Autumn fern is easily recognizable in spring when new growth is bronze colored.  I removed and trashed that plant. 

This year, I noticed in my creek several evergreen ferns that appeared to be a type of wood fern (Dryopteris).  There were two large ones on the side of the creek wall and one small one on a rock in the middle. When new growth showed up, it was clear they were Dryopteris erythrosora.

Where are these coming from? Several folks have reported that the spread of this fern is facilitated by waterways. Spores and young plants get washed downstream, especially during heavy rains when creek banks are scoured by rushing water. Downstream they will get lodged into new areas and the infestation spreads.

While there is very little information out there on invasive spread, a paper published in 2018 specifically addresses the spread in Georgia. The paper is by Tom Diggs (professor at University of North Georgia) and H. Umstead (student). This paper was shared with me by Tom after an online discussion of this plant in 2021 after I found it in DeKalb. The paper discusses a population in Alpharetta, GA (not terribly far from me) but also documents some of the reported locations in Georgia and the southeast.

Autumn fern fronds

I have since removed those ferns from my creek and securely trashed them. I’m not sure where they originated since my immediate upstream neighbor doesn’t have them. I’ll be monitoring my creek more closely and I’ll be checking my neighbor’s section as well. Unfortunately, I don’t have access to monitoring downstream, but you can be sure that I’ll do everything I can to stop the spread in my area. If you find it in the wild, be sure to report it.

Please do not buy this fern, remove it if you have it (especially if near waterways), do not donate it to local plant sales. We’ve seen so many plants become invasive (ornamental pear, anyone?), if we could learn to stop things when they first start to show tendencies, we could make a difference.

Fronds are hairy and red

Sori on Autumn fern

In Search of Edna's Trillium

 

Edna's trillium (Trillium persistens)

This past week I had a chance to participant in a rare plant survey. Georgia DNR personnel in the Nongame Conservation Section do periodic plant surveys to measure how well rare plants are doing in known locations. This year’s survey was a follow up to one done in 2021. The plant being surveyed is a small trillium known as Edna’s trillium (Trillium persistens). The common name honors Edna Garst who suspected it was unique in early 1970 after finding it near Lake Yonah, a reservoir that sits between Georgia and South Carolina. The species name persistens was chosen because the plants often stay present after other trillium species have gone dormant.

The survey was led by DNR staff. We learned that this trillium species prefers pine-hemlock forests and is potentially affected by the decline of hemlocks (Tsuga sp.) because of the woolly adelgid pest. The terrain was extremely steep, and the area had plenty of downed trees and limbs; we passed at least one hemlock with an active woolly adelgid infestation. The area was also very thick with Rhododendron, both maximum and minus species. There were times when I felt like this is what early explorers must have traversed, nicknaming such places as ‘laurel hell’ (Rhododendron maximum is called ‘great laurel’).

Flowers turn to pink as they age (Trillium persistens)

While it was a challenging trek to count these plants, it was a thrill to be there and to find these little plants tucked here and there. It was fun to discover what else lived among the trilliums and the rhododendrons. Three plants were in particular abundance: variable leaf ginger (Hexastylis heterophylla); sweet white violet (Viola blanda); and fuchsia-colored gaywings (Polygaloides paucifolia). Some populations of gaywings were so numerous that we could see them from a distance. Robust clumps of ginger had ornate flowers to discover if one would only brush away the leaf litter to see them (and I did!).

Variable leaf ginger (Hexastylis heterophylla)

A more mottled leaf and flowers

Close up of flower (H. heterophylla)

Other plants we saw included beetlewand (Galax urceolata); the flowers were just emerging but it was the foliage that was so handsome: both green and burgundy leaves were present. Ferns were abundant, especially in the damp areas where cinnamon fern (Osmundastrum cinnamomeum) fronds were starting to rise above their thick rhizomes. In the drier areas and on slopes, Christmas fern (Polystichum acrostichoides) was the dominant one. Interesting trees included witch hazel (Hamamelis virginiana), silverbell (Halesia), sweet birch (Betula lenta), and Fraser’s magnolia (Magnolia fraseri). Highland doghobble (Leucothoe fontanesiana) tried to hobble us where it grew thickly near the streams.

Gaywings (Polygaloides paucifolia)

Galax urceolata

Plant surveys are important work. Volunteers like me provide just a small amount of help; it is the staff at GA DNR that are pulling these together and doing most of the work. There were 7 of us on this all day trek; 5 of those folks were GA DNR botanists and ecologists. I encourage you to support their work by advocating for them and even by donating to the Nongame Conservation Section.

Sweet while violet (Viola blanda)

Highland doghobble (Leucothoe fontanesiana)

April 2022 Moment in Nature

Box turtles seem uncommon in my area. I feel lucky to see one or two a year in my garden. This year's view was especially early as it appears this guy was just starting to emerge from his winter hibernation in a thick covering of leaves. Box turtles can live to be 50-100 years old! Hopefully I'll see this guy for years to come.

Get out there and find #amomentinnature. So much is just waiting to be noticed and appreciated.

Phlox – An American Perennial

 

Pink (Phlox amoena); white (a western alpine Phlox)
and blue (Phlox divaricata)

From spring to summer, native Phlox are one of the joys of my garden. Did you know they are uniquely American? Of almost 70 species, all but one are native to the continental US, that one species is native to Alaska, and 14 beautiful species are native to Georgia. They are hardy, adaptable, and quite colorful. All are considered to be perennial except for one.

Early naturalists in what is now America described the first species by approximately 1680. The genus was officially named Phlox by Carl Linnaeus using the Greek word for “flame” to describe how colorful they were. As plants were sent back to England, Phlox became an early garden favorite. A good reference book is Phlox:A Natural History and Gardener's Guide by James H. Locklear.

Many Phlox species have a light fragrance, and they are pollinator favorites. We have species that bloom early in the spring, others in mid-spring, and others in summer. There are species that are low and creep and others that stand tall. American phlox come in a range of colors: from deep pink, to white, to blue!

Phlox can be recognized (or differentiated from other plants) by two characteristics: their leaves are oppositely arranged and the number of petals in their flowers is five. In spring, some people mistake the non-native money plant (Lunaria annua) for phlox but it only has four petals. 

Phlox subulata at a home near me

Moss phlox (Phlox subulata) is an early bloomer that has long been a favorite in the South where it is sometimes called ‘thrift’ because of its color resemblance to the plant Armeria maritima which has that common name. Many an old home has remnants of earlier plantings, the bright pink flowers sometimes just peeking out of grasses in overgrown areas. Another early spring, creeping species is trailing phlox (Phlox nivalis). I believe this is the species planted among graves in old cemeteries. Both species do well in full sun and lean soil and generally have bright pink flowers (although nurseries have bred P. subulata into a wide range of colors).

Phlox nivalis at a cemetery near me

Two early bloomers for shade are woodland phlox (Phlox divaricata) and creeping phlox (Phlox stolonifera). Both are blue and a joy to see mixed along with other spring bloomers like spotted geranium (Geranium maculatum). Woodland phlox is the more commonly available thanks to nursery cultivation.

A wild Phlox divaricata in NW GA

Phlox stolonifera in my garden

Mid-spring to early-summer bloomers include quite a few species: hairy phlox (P. amoena), downy phlox (P. pilosa), thickleaf phlox (Phlox carolina), and smooth phlox (Phlox glaberrima). Phlox glaberrima was recently collected in a wide range of natural colors in northwest Georgia and propagated by Henning von Schmeling of the Chattahoochee Nature Center (such as the white one shown below). All of these are usually pink.

Hairy phlox (Phlox amoena)

Downy phlox (Phlox pilosa)

Thick-leaf phlox (Phlox carolina)

Phlox glaberrima 'Malcolm Hodges'

The latest species to bloom is aptly named summer phlox (Phlox paniculata). It is also the tallest as far as I know. It has been widely propagated over the years into a number of cultivars in a range of colors but it is most naturally pink. This one has had mildew issues and cultivated varieties have tried to address that. My favorite cultivar is one that was naturally found with numerous, smaller flowers called ‘Jeana.’

Pale color form of Phlox paniculata

Phlox paniculata 'Jeana'

Five Georgia species which I have not seen are large-leaf phlox (Phlox amplifolia) from north Georgia; the annual phlox (P. drummondii) which has reports from south Georgia; Florida phlox (Phlox floridana) from southwest Georgia; and speckled (Phlox maculata) and mountain phlox (Phlox latifolia or P. ovata), both from northwest Georgia.

If you’re interested in how Phlox might do for your garden, Mt. Cuba Center in Delaware evaluated numerous species and cultivars in their Phlox trial; there are summaries for sun and shade. Spring sales are a good time to pick some up.