Sunday, January 26, 2020

Winter Weeds in the South

Here in the southeastern U.S. we are fortunate to have a number of evergreen plants during the winter. Not all of those plants are native, of course, and a few of those non-native ones are even invasive. Since evergreen plants really stand out in the winter, now is a good time to work on removing the invasive ones while you can see them clearly.

I find six evergreen invasive plants in my area: 
  • Two species of Asian privet (the small-leaved Ligustrum sinense and wax-leaf Ligustrum japonicum),
  • English ivy (Hedera helix), 
  • Two species of autumn olive (tardily deciduous autumn olive Elaeagnus umbellata and thorny olive Elaeagnus pungens), 
  • Grape holly (Mahonia bealei, which is blooming now with yellow flowers), 
  • Heavenly bamboo (Nandina domestica, which has visible fruit now), 
  • Japanese honeysuckle (Lonicera japonica).

Mahonia bealei flowering when
no native bees are out
These are all woody plants and can be removed in various ways.  If they are young and small, try pulling them out now while the ground is relatively moist (wear gloves to ensure good traction and minimize any reaction – plants like English ivy can cause a rash).

If they are too large to pull, you can cut them or cut into their bark to reveal the cambium layer and carefully apply (consider using a foam paintbrush) a bit of brush killer on the stump or cut area.  At the very least, remove any berries on the plant and mark the plants with some bright string or flagging tape (available at home improvement stores) so that you can come back to remove them properly when you have help.  Bag up any berries and place them in the trash.

I've removed dozens and dozens of seedlings from my property over the last 16 years. If I hadn't, I'd have lots of each of these six groups growing in my yard. How do they get here? Mostly by way of birds but other animals might carry in some seeds ... all of it pooped out along the way. Every seedling you and I remove means not just that plant is gone but all its future progeny.

Japanese honeysuckle
Chinese privet

Interested in identifying other invasive plants? This is a good website – detailed photos for identification and links to learn more about methods of control for invasive plants found in Georgia.  Plants are listed both by common name and by scientific name – use your browser’s “Find” function to search for what you’re looking for (but be aware that the common name be not be the same as what you know it as, so search by scientific name if possible).

Removing invasive plant seedlings now is easy and a good excuse to be outside. Plus the winter rains make for easy pulling in Georgia.

Silvery backside is a good way
to identify the leaf of Elaeagnus pungens
Mahonia bealei seedling

Sunday, January 19, 2020

Native Palms of Georgia

Even though we’ve been having a fairly mild winter, who doesn’t long for summer landscapes and warm areas with palm fronds waving? Someone recently asked about native palms so I think now is a good time to talk about them. Georgia has four species of native palms, all of them in the Arecaceae family and native mostly to the Coastal Plain, although one has Piedmont range. Two of them can be grown well into the Piedmont (and gardeners do grow them, I have one myself!).

Cabbage palm (Sabal palmetto) on Jekyll Island, GA
Let’s start with our only “tree” palm. Cabbage palm (Sabal palmetto) is a trunking palm up to 60 feet tall. Its natural range in Georgia is the maritime coastal plain. Flowers appear on branched clusters up to 6 feet long, blooming May-July, and the fruits are shiny black drupes. The name "cabbage palm" comes from its edible immature leaves, or "heart," which has a cabbage-like flavor.

One thing that was confusing to me initially is the appearance of the trunk: sometimes it would be all smooth, sometimes it would be halfway smooth, and sometimes it wasn’t smooth at all! The old leaf bases do not always naturally detach from the trunk; these are called ‘boots.’ In landscaped areas, the gardener might remove them manually but there are some health risks to the tree in doing so (I've included a picture at the end of this post with the smooth look.)

Blue stem palmetto (Sabal minor), shown at left, is shrubby with no visible trunk above ground. It has large fans (leaves) like the other palms, but the petiole of the leaf has no teeth (which is useful in comparing it to the similarly-sized saw palmetto which does have sharp teeth). The clusters of tiny white flowers turn to clusters of small, hard blue fruits. This is one species which has native range into the Piedmont; I grow it in my backyard, although my county is not part of its actual range.

I actually got this species by accident – the plant that I bought was labeled ‘needle palm’ which is another cold-hardy species. It’s a handsome plant and looks cool near the swimming pool, but I’m actually starting to see a lot of seedlings pop up around the garden.

Saw palmetto (Serenoa repens) closely resembles blue stem palmetto but it does have a couple of differences. Its prostrate stems can sometimes be visible above ground and it can grow into a large mound, creating the distinctively beautiful sweeps of shrubby palms in pine flatwoods and maritime forests. The petiole of the leaf has numerous sharp teeth, hence the common name "saw palmetto." This species is not hardy enough to grow outside the Coastal Plain.

Saw palmetto (Serenoa repens)
The needles of Rhapidophyllum hystrix

Needle palm (Rhapidophyllum hystrix) is also a shrub; it is distinguished by the sharp spines found at the base of mature leaves, at the center of the plant, persisting even after the leaf is gone. This palm does not have an elongated cluster of flowers; the tiny flowers are held in tight clusters at the base of the plant, with male and female flowers on different plants. Fruits are reddish brown. This species will grow in the Piedmont; one of our members had a beautiful specimen at Big Canoe in Pickens County and these pictures are of that plant.

Sunday, January 12, 2020

Where Did These Plants Come From?

I recently visited a relatively urban site that used to be near an old mill.  The site has received a grant to restore 1.5 acres of riparian corridor and 500 feet of creek in north Atlanta. I was there to help identify what plants were on the site. This inventory will be used to document the change as well as understand what native plants are there to be preserved.

No one lives on the site now but it is surrounded by buildings, both residential and commercial. As you might expect, if it needs to be restored then it has some invasive plants. English ivy (Hedera helix) and silverthorn (Elaeagnus spp., two species on site) were the two most prevalent plants. Mahonia bealei and privet (Ligustrum spp, two species on site) were there as well. Just getting started was bush honeysuckle (Lonicera maackii), but the vining Japanese honeysuckle (Lonicera japonica) was well established. Two non-native ferns were there – Japanese holly fern (Cyrtomium falcatum) and Autumn fern (Dryopteris erythrosora).

Autumn fern (with native Christmas fern below)
None of these plants were planted by people here. Where did these plants come from? They came via birds. They came via travelling mammals. They came via any critter with the capability of consuming a berry or seed and then depositing (largely by defecating) it further away.

They came as one: a seed slipping through the leaf litter until it reached fertile soil. Another one arrived and made its journey to the soil. They flowered and insects pollinated them, allowing them to multiply again and again. Some crept quietly and steadily, year after year, increasing their mass and their reach.

They were ignored by man, overlooked and unidentified. The fruit of each was carried further into the property, creating even more, choking out the light in some cases and hogging the water and nutrients as well. Native plants, some small and ephemeral, shrank back. The biodiversity of the environment decreased until the newer plants dominated the space. English ivy covered the ground and thick stands of evergreen shrubs overtook trilliums, bloodroot, and Solomon’s seal, perhaps. Will we ever know what was lost?

English ivy-dominated slopes; Japanese holly fern in cracks of the mill wall

Restoration projects sometimes report of returning native plants once the invaders are removed. Nature can be resilient if we help it in time. Free of the stifling vegetation, these special native perennials may have enough energy to come back.

I hope to write about the success of this project in the future. There were some very good native plants there, pushed back but still there. Once the sunlight hits the ground, native plants may re-emerge (some non-natives too but they won’t last!). Local restoration projects are a great way for people to get involved in the health of their community. Even people without their own garden can make a difference this way. If you have a park near you, offer to identify and remove non-native plants and see what grows thanks to your efforts.

The slope above the creek with ivy, mahonia, privet, and more

Sunday, January 5, 2020

Valley of the Giants

Eastern hemlock (Tsuga canadensis)
We have giants in Georgia? Apparently, we do! I know a lot of people bemoan that time-waster known as Facebook, but it can be used for good; that is how I find out about new (to me) plants, hear about new books and events, and even learn about places. In mid-December, a friend posted about visiting the Valley of the Giants near Suches, GA.

Looking at giant trees is a great winter activity and I was intrigued. In addition, I had some vacation days to spare and December was having some very pleasant weather days. My friend said the 1990 guide from The Georgia Conservancy had a good description of this old-growth forest area. I dug out my copy (with preface by Jimmy Carter!) and looked it up. The description tells of “widely spaced specimens of white and northern red oak and black birch, but the largest trees are giant tulip poplars ….”

My husband readily agreed to a Christmas Eve hike and away we went. I have been up that way many times for trips to Sosebee Cove and Woody Gap; this trip took us past Woody Gap (plenty of people were hiking that day) and along a stretch of Hwy 60 that I haven’t traveled, on past Stonepile Gap (which is being turned into a roundabout). We stopped to admire a wooden eagle and its faux nest, chatting with one of the locals who asked if we were ok.

I had to appreciate this!
Tiarella cordifolia with good color

The trailhead on an old Forest Service road was a little hard to find – we overshot it initially but managed to figure it out despite a lack of cell signal (frankly, it was my husband who saved the day).  The trail was thick with hardwood leaves, but a few bright leaves of foamflower (Tiarella cordifolia) peeked out. American beech (Fagus grandifolia) leaves waved in the breeze, still stuck to branches of saplings along a nearby creek, and large mountain laurel (Kalmia latifolia) added some green.

While there was plenty of Christmas fern (Polystichum acrostichoides) to be seen, I was thrilled to notice the less-common marginal fern (Dryopteris marginalis) as well. This evergreen wood-fern gets its name from the arrangement of the sori on the margins of the pinnae (flip the frond over to see). Understory plants also included silverbell (Halesia), serviceberry (Amelanchier), buckeye (Aesculus), smooth hydrangea (Hydrangea arborescens), and I spied the old bloom stalks of black cohosh (Actaea racemosa).

Marginal fern
Marginal fern sori

After walking a good bit, we finally entered the first area of large trees. The biggest ones were the tulip poplars (Liriodendron tulipifera) and several had damaged tops from storms.  The winter landscape was actually useful in being able to see just how big they were. There were also quite a few very large white pines (Pinus strobus) and Eastern hemlocks (Tsuga canadensis). The path was blocked at one point by a recently fallen hemlock, but we scrambled around it (at several earlier points we’d ducked under much older fallen trees – this was indeed a challenging trail).

Large white pine (Pinus strobus)
Large Liriodendron tulipifera

Interesting finds included an old bald hornet nest on the ground and old logs covered with fingers of moss. Some of the moss on logs was thick enough to grow foamflower (imagine a flowering foamflower on a log in spring!). Unfortunately, some of the smaller hemlocks along the path appeared to have woolly adelgid pests on them. All in all, it was a fun adventure and a beautiful day in nature.

Old hornet nest; they make a new one each year