Solomon's Seal (Polygonatum biflorum)

The arrestingly-named Solomon's seal (Polygonatum biflorum) is a handsome herbaceous plant. Its obscure common name is well-paired with its genus name, Polygonatum (which comes from the Greek gonatos)  and means "many-kneed." Do plants have knees? What does all this mean? We won't dwell on the unanswerable. There are a few dozen species in the genus, but most find their home in East Asia, far from Caddo Parish, Louisiana. 

As far as names go, we have a problem; our current signage turns out to be inaccurate. The arboretum catalogue shows two collection dates for hairy Solomon's seal (Polygonatum pubescens), both dating from the '90s. In 1991, Professor Ed Leuck collected a few plants from within Shreveport's city limits, on Line Avenue. A healthy patch still grows under the origianl red buckeye plants. In 1996 Jack Price of Blanchard donated six pots. Those plants have thrived on the southwest side of the long wooden bridge that runs from the Student Union Building to Mickle Hall. This patch continues to grow out into the lawn. Plants were collected from the grassy area and then transplanted to other areas of the arboretum, resulting in two additional patches of Solomon's seal. So, there are four total patches of Solomon's seal, and the original two patches are marked with green signs that read 'Solomon seal (Polygonatum pubescens)'. 

This is a relatively new patch of Solomon's seal. In 2023, we relocated a couple of plants to this spot, alongside a young black cherry (Prunus serotina). The black cherry has since grown tall, shading the Solomon seal.

The fruits were noticed several weeks ago. 

Leaves alternate and have noticeable ridges or veins.

As the bell-like flowers of Solomon's seal descended daintily and prettily from the stalks, so now do the berries.

These fruits greatly resemble blueberries, although they are much more firm. Be careful! NC State Extension claims, "The berries, if eaten, are poisonous."

Dark blue round fruits measure less than ½ inch across.

 

Squeezing the large fruit opens the bright green interior, revealing numerous seeds. Seven seeds came from one fruit. Another yielded four seeds.

 

Looking at the current classification information for Polygonatum in the United States shows P. pubescens and P. biflorum are the two major species east of the Mississippi. However, a distribution map clearly shows that P. pubescens is not found in the Deep South; its homelands begin in the mountainous, cooler climates of Kentucky and Tennessee. Since the distribution map for P. biflorum makes much more sense in covering the entire eastern half of the USA, we needed to take a closer look at the plants currently growing in the arboretum.  

Descriptions for both species state the fruits are similar. Descriptions differ for flowers, leaf size and shape, and the presence of hairs. Since flowers aren't available in late summer, all four patches of Solomon's seal were studied for leaf size and shape and the presence of hairs. 

This egg-shaped leaf suggests P. biflorum.

These narrower, lanceolate-shaped leaves suggest P. pubescens. 

These leaves are from two different patches. Do we have two different species or different light-conditions? The top leaf was found in full-shade. The bottom leaf was found in partial shade.

 

 

Within the arboretum's collection, leaf size and shape suggest that we have two different species of Solomon's seal. However, the common names dwell on the presence of leaf hairs, and although the leaves varied in size and shape, no hairs were seen on any stems or leaves. All surfaces felt and looked smooth. 

This is the underside of the leaf. We see spots, but nothing fuzzy. 

The underside is smooth. Leaves and stems from all four patches were examined, and nothing resembling hairs was detected. 

Based on species distribution and the total absence of hairs, we shall change the arboretum catalogue to note that we have Polygonatum biflorum, rather than Polygonatum pubescens. And, in the spring, we must study the flowers to see if they can give us any other clue as to the correct species label.

 

 

For more information about this species, please consult the following online sources:

USDA Plant Database Info for Smooth Solomon's Seal

USDA Plant Database Info for Hairy Solomon's Seal

Flora of North America Species comparison for these two plants 

Plants of Louisiana

NC State Extension 

Black and Yellow Garden Spider (Argiope aurantia)

Boo! Autumn is a season for creepy-crawlies, spiders, and bugs. This is a female Argiope aurantia, which is Latin for 'golden silver-face.' This name makes a lot of sense, given that the cephalothorax (meaning head-body) is silver while the abdomen is gold and black. We know it's not a male because males of the species are much smaller, brown, and just plain ugly.

"Oh... what tangled webs we weave...." As members of the Araneidae family, these spides are "orb-weavers" and produce the classic spider-web.

This specimen was photographed on September 28, 2024, next to the long white wooden bridge in the arboretum.

 

For comparison, this photo is from insectidentification.org (image credit: Arch Baker).

Volunteers in the Arboretum

The overgrown area near the Student Union Building, previously referred to as 'the volunteer recruitment zone' or 'the Arboretum's unintended creche', is slowly being cultivated: we have removed Groundsel shrubs (Baccharis halimifolia) and Chinese privet (Ligustrum sinense). This week, we cleared around the sycamore (Platanus occidentalis), making it possible to read the sign and walk around the trunk.

The arboretum has only one sycamore on display, so we want to raise this tree's profile. Visitors ought to be able to read the sign and examine the trunk without too much difficulty. Right now, it looks a bit too hazardous; you might come away with some dewberry-scratches on your shins. 

There are numerous vines, little shrubs, and trees growing around the base of the trunk. Unfortunately they must be removed for the health and visibility of the sycamore.

The base of the trunk is now revealed. Several small trees were removed; elms (Ulmus sp.), oaks (Quercus sp.), and one black cherry (Prunus serotina) were snipped. We do not want any other trees to grow up next to the sycamore trunk, so it was an easy decision to remove these volunteers.

We used a lawn mower to cut the grass, making this space more inviting to foot traffic.

Several pieces of crossvine (Bignonia capreolata) had to be pulled from the trunk.

Dewberry (Rubus trivialis) was cleared away from the base of the trunk. This species comprised the bulk of the plant material surrounding the tree.

Dewberry vines have painful prickles. It's best to wear long pants when walking near a dewberry patch, but as the prickles snag on clothes, you still need to watch your step even if dressed defensively.

A small yaupon holly (Ilex vomitoria) was growing near the trunk, but not next to it. Yaupons do very well in the soil of the arboretum and they are common volunteers. This little shrub was allowed to stay for now and might very well be added to the catalogue.

Luckily, there were not any passionflower vines surrounding the sycamore. The abundance of Gulf fritillary butterflies tells us that we ought to refrain from pulling any passionflower―we want the caterpillars to have plenty to eat!

Cleanup Operations

Today, more than four months since it fell, we decided to complete the water locust (Gleditsia aquatica) clean-up operation. Most of the mess was cleared away during the month of May. Over the summer, a very large section of the trunk remained wedged inside the yaupon holly on which the water locust had collapsed.

 

A section of the water locust trunk is pictured on the far right of the photograph. It had been resting in the yaupon holly shrub for several months.

 

As this tree trunk was suspended off the ground, we are "stumped" as to its current rotted condition. There are numerous mushrooms growing on it. Why would a rot-resistant tree have rotted so quickly?

 

A chainsaw was required to reduce the trunk to movable pieces.

All cleaned up! The water locust is gone, which is sad, but the good news is that we have a young water locust to plant this winter.

Arboretum Cleanup: Catalpa (Catalpa bignonioides)

Maintaining trees in an urban landscape often requires pruning. Removing lower branches from trees allows for more foot traffic in proximity to the trees, and it also increases visibility, which is a safety concern. Some trees require more pruning than others. Today we'll take a look at one of our catalpas, which is in rude health. See previous posts on the history of this tree here and here.

 

The catalpa (Catalpa bignonioides) is pictured center. What a gorgeous tree. It is only eleven years old! Take a look at the trunk: there aren't any branches near the ground.

Even though the lower branches have been removed from the trunk, branches further up the trunk droop low to the ground.

The leaves and seed pods are only a couple of feet above the grass.

 We pruned this tree and its partner (not photographed), which lies across the drainage canal. With the lowest drooping branches removed, we see more of the landscape, and, more light is now available to the little trees and shrubs recently planted. The catalpa will hopefully invest its energy in its upper branches rather than the ones nearest the ground.

Tree of the Week: Sweetbay Magnolia (Magnolia virginiana var. australis)

Thankfully the brutally hot weather has passed: high temperatures are now around 90℉. This past week, northwest Louisiana has received scattered rain showers, some of which have been heavy. Interestingly, the vegetation in the arboretum, especially the grass, has recovered quickly. The landscape is mostly green, especially since the mower has chopped up the majority of the fallen leaves. Unfortunately, there are lingering signs of the damage caused by the August heat wave. Below, we have pictures of one such case: an evergreen sweet bay magnolia with an alarming number of brown leaves.

Our tree of the week is an evergreen sweetbay magnolia (Magnolia virginiana var. australis). This tree was purchased and planted in 1997, making it at minimum 26 years old. It has grown happily in the arboretum and lived true to its 'evergreen' designation. You can read more about its history on an older blog post, found here.

At this time, the brown crown of the sweetbay is conspicuous in the mostly green, or yellow-green, landscape.

Approaching the sweetbay, we see brown leaves up above and green leaves at eye level.

Browned, withered twig of Magnolia virginiana var. australis, photographed September 23, 2023

Healthy twig of Magnolia virginiana var. australis, photographed September 23, 2023

Looking at the multi-stemmed base, we see plenty of green leaves. So, we know that this tree is very much alive, although we cannot say what kind of condition it is in. It will be interesting to see what happens to the upper parts of the trunks.

Tree of the Week: American Beech (Fagus grandifolia)

There are two American beech trees in the arboretum collection. Both have ripening fruit falling this week, and both can be found in the same area of the arboretum, near Hamilton Hall. Jack Price donated these two trees and they were planted during September 1988, which means they are both, at minimum, 35 years old. The pictures below are of a single specimen, the larger of the two trees. It's larger, perhaps because over the decades it has had access to more sunlight.

Our tree of the week is pictured center. It grows at the top of a slope near Hamilton Hall. To its left we see a mature loblolly pine (Pinus taeda) and a mature water oak (Quercus nigra). Given the proximity of the much older pine and oak trees, our American beech has significant competition for water and sunlight. Fortunately, the American beech has a reputation for being shade tolerant. A small chinquipin oak (Quercus muehlenbergii) is pictured on the far right, near the cat (Felis catus). Meow!

The American beech grows next to the intersection of two gravel paths, necessitating the removal of its lower branches.

From another angle, we see that the straight trunk appears to lean slightly to the left.

On the gravel path beneath the American beech, we see its fruits and husks, mixed in with some pine straw of course.

Looking upward from the ground, we see a single fruit. Since the lower limbs have been removed, without the aid of a ladder, we cannot closely examine the fruits that are still attached to the tree.

However, there are plenty of leaves to study at ground level.

It appears that the American beech suffered during the August heat wave: leaf edges are crispy.

This tree grows in the older section of the arboretum, and while the irrigation system was running at reduced pressure, it was still operational during much of August, unlike on the other side of the arboretum, where the irrigation system was completely off for two weeks.

With a ladder, we can see a whole lot more! The interesting fruiting structure, called a cupule, is cracked open.

Twigs were snipped for measurement and comparative photos. This twig does not have any fruit.

We see simple, alternating leaves with serrate margins and short petioles, as well as sharply pointed dark brown leaf buds.

Turning the leaves over, we can better appreciate the highly textured leaf surface resulting from the pronounced venation.

Also, zooming in on the twig, we see white fuzzy stuff on the leaves and twig. A twig with fruits looks a little different....

This twig was snipped with the aid of a ladder. Several cupules are attached. All are open and intact.

This cupule hasn't dried out completely. Although not visible from this angle, the cupule has opened slightly.

Zooming in on the twig, we see that it is significantly fuzzier than the non-fruiting twig, and there is a pointed leaf bud tucked in beside the cupule.

The cupules measure between a ½ inch and ¾ inch in length, and they are uniformly covered in curved spikes.

The cupules are fuzzy. The little spikes look threatening, but they are harmless. Compare this with the vicious hybrid chestnut in the arboretum collection (see Dunstan here).

This cupule had to be pulled apart to reveal the fruits of the American beech, two edible nuts, which are still green. Each nut has three flat sides. Don't eat too many.