Sweetgum (Liquidambar styraciflua)

Currently we have only one sweetgum (Liquidambar styraciflua) in the arboretum collection, and it is still very young. The sole specimen originated from a trip to East Texas in 2022. That fall, we collected a pocketful of gumballs from a wooded area in Cherokee County, Texas, close to the small town of Maydelle. Those gumballs were brought back to Shreveport and shaken into a pot of dirt where the seeds overwintered. Three seedlings came up the following spring. On March 10, 2025, we planted one of the three on campus, outside of the arboretum proper: it's on the Fitness Center lawn, between the Fitness Center ramp and the Cline Hall parking lot. Today, we have a hearty young specimen that nicely displays the characteristics of the species. The following photos show the tree after three years of growth. 

An old sign for a new tree. We like to recycle and re-use our materials in the arboretum.

 

The 3-year-old tree is 21 inches tall with a straight and sturdy trunk.

This one is planted *near* the parking lot but not next to the parking lot. Looking into the future, we see a towering tree with an excessive number of fruits that are falling on the *grass* rather than the cars and pavement. Nobody likes a "trash tree"....

 

While this tree isn't quickly growing tall, it is forming a thick trunk. Have the interesting bark formations drawn your attention?

Young sweetgum stems have irregular 'wings' or corky ridges, like our winged elm (Ulmus alata). The contrast between the green branches and the grey plates is distinctive.

This little tree is ready for spring. 

 

Fresh green leaves unfurl in a bold salute to Spring.

 

We see the characteristic sweetgum leaves in miniature.

Now that it's well-established, will it show rapid and vigorous growth this year?

Tree Removal: Pawpaw, Sweetgum, Mulberry

Today we continued normal cleanup operations in the Arboretum. This customarily involves cleaning up the paths, picking up fallen limbs, moving gravel around, and today a special task: cutting down some trees and removing stumps.

First, a water leak in the arboretum, down the slope from Mickle Hall, required a lot of dirt work. This area is in shambles, but there is really no alternative. Our native clay can be quite an adversary. Don't try to walk through this area; just go around.

Onto the main tasks.... Here is a sweetgum (Liquidambar styraciflua) stump, which you can see on an earlier blogpost here. In that post we said "Now all that remains is a two-foot stump which will be removed at a later date." That day has arrived.

Resprouting, this tree is still alive. This photo was taken after all of the new growth was trimmed.

Afterwards, we have a more-or-less flat area that will not be a tripping hazard. The roots were not removed, which means that we have not yet seen the end of sweetgum shoots.

Next we have a highly suspect pawpaw (Asimina triloba), which you can read more about on an earlier blog post, here. This tree has had a broken crown for nearly a decade, which may have led to some health problems. Recently it has taken a turn for the worst, so now we must make an assessment. Before we cut the tree down, let's inspect the specimen to determine its condition.

 

The bare pawpaw trunk is pictured center. Louisiana palmettos and titi shrubs are in the background.

This image becomes more unsettling the longer you look at it. Here you can see fungal pink slime oozing from the bark and forming bubbles. What on earth is this?

This rotten branch nub was characteristic of the whole tree.

Scoring thin bark will often reveal healthy green cambium underneath. Scoring this pawpaw revealed dead tissue and only excited the ants and other bugs crawling across it. Snapping a few twigs, which should have been green and springy, verified that this tree is completely dead. Cutting it down released a horrendous mushroom-like smell.

All gone, and only a few blog posts to tell the tale.

This cross section reveals a rotten tree. It may not be immediately obvious from this photo, but the inner rings of the tree were sickly green and oozed.

The lower feet of the trunk served as a nursery for untold billions of fungal spores and the entire surface of the bark had turned green. The white specks were tubular filaments rising off the surface of the bark and ending in a nodule.

Finally, this undesirable specimen is a hybrid of Morus rubra, the red mulberry, and an Asian species. Since we want to preserve native species, we will remove this one as we have removed other white-berried and black-berried mulberries in the arboretum.

We see leaves of the characteristically variable Morus genus.

Our mulberry hybrid was dissassembled.

This area is already a major tripping hazard due to holes and uneven ground, so we've sawed the stump down as low as possible. Cutting around soil will quickly dull your chainsaw blade, but there's no helping it.

Autumn is a great time of the year for these kinds of clean-up operations. Look around and you'll find plenty of work to do!

Tree Removal: Sweetgum (Liquidambar styraciflua)

Yesterday, we removed the arboretum's only remaining sweetgum. This is unfortunate, but necessary, as the tree was doomed by two unfortunate circumstances. Back in 2021, we resolved to remove this tree and its day has come.

The base of the sweetgum trunk is pictured on the left side of the photograph. This photo exhibits the extreme lean of the trunk. As the tree ages and the trunk grows larger, the chance of breakage and a dangerous incident only becomes greater.

This photo shows where, several years ago, bark had been peeled off by desperate squirrels. This damage would one day leave the tree vulnerable to disease and weather. Along with its lean, this means the tree will never be a safe, healthy adult specimen.

First we cut out the upper branches.

Even a small tree like this creates a large pile of branches.

Now all that remains is a two-foot stump which will be removed at a later date.

Although we do not have an official sweetgum in the arboretum catalogue, volunteers can be seen on the grounds of the arboretum. Interestingly, there are at minimum two young sweetgums growing in proximity to the remaining stump. So, we will see how these little trees grow this spring and summer, and perhaps one will be a suitable addition to the catalogue. Also, the arboretum curator germinated sweetgum seeds collected from Maydelle, Texas; these individuals are expected to enter the catalogue next year, after they grow a little taller.

Tree of the Week: Sweetgum (Liquidambar styraciflua)

For the past two weeks, you may have noticed ripe fruits on the ground around our young sweetgum (Liquidambar styraciflua.) Some gum balls can be found still attached to the tree. This tree is approximately 10 years old, and over the past several years we have followed it closely. Its exact age is nevertheless unknown due to its origin as a volunteer. You can read more about this individual here, here, and here. 

 

Sweetgum fruits (or 'gum balls' as they are popularly called) are generally thought of as troublesome and trashy. It's unpleasant, and potentially hazardous for those traveling barefoot, to step on a gum ball―they are large and prickly. Furthermore, on the ground under mature trees, the fruits are numerous.

But gum balls aren't all bad. A local Shreveport resident, Linda, recounts how as a girl of four living in rural Rapides Parish, she and her older sister would use gum balls to make Christmas tree ornaments. The sisters would wrap gum balls in pieces of aluminum foil, pressing it into the prickly fruits, and then hang the shiny orbs from the branches of their Christmas tree. Attaching a small bow made from scrap pieces of ribbon adds a little holiday color.

 

Another Shreveport resident, Sidda Ogea, has also found beauty in the prickly gum balls. Sidda spray painted the fruits gold and incorporated them into a holiday display, or altar, celebrating the Virgin Mary.

 

Working closely with sweetgum fruits will teach you something about the reproductive cycle of this species. Shaking or thumping these fruits releases seeds and other tiny pieces of plant material, some kind of natural packing material.

 

The seeds are the larger pieces. They measure a ¼ of an inch in length. We ought to plant a few seeds in the arboretum to have a replacement for our current specimen.

 

 

Tree of the Week: Sweetgum (Liquidambar styraciflua) and a special guest

Our tree of the week, a young sweetgum (Liquidambar styraciflua), grows on the grassy slope near Cline Hall Dormitory. It is pictured center (leaning to our left) alongside a groundsel bush (Baccharis halimifolia).

 

For the past few years we have recorded the development of this sweetgum on the blog. You can read about it here and here. Last year, this individual was tagged for removal, but for one reason or another, it thankfully remains standing.

Severe damage to its trunk was the reason it was tagged for removal. In 2020, the arboretum's squirrels made deep cuts into the bark. Why were they peeling bark from the tree? We're not entirely sure, but trees are probably very fond of owls, hawks, and snakes. Those wounds have healed, but the damage is permanent, making the tree susceptible to enemy invaders, particularly fungi and insects. An intact layer of bark is essential protection for a tree to last into maturity.  Consequently, we will be keeping an eye on this sweetgum; it is still a candidate for removal.

 

Looking at the bright green leaves, you wouldn't think that this tree was handicapped, especially if you look a little closer to notice the inconspicuous fruits, the infamous gum balls.

Allowing this young tree to stand another year or two ought to insure a replacement for the arboretum catalogue.

 

This sweetgum is also of interest this week because of its guests. Caterpillars have taken up residence in a few localized areas of the canopy. The caterpillars have built white, gauze tents among the leaves, which they are eating. According to our research, they appear to be fall webworms (Hyphantria cunea). Given the season and their activity, that common name makes a great deal of sense.

 

Although they produce a web-tent that some people might find "yucky," this silk might be worth its weight in gold. Unfortunately, it doesn't weigh much. The LSUAg Center informs us that while unsightly, fall webworms are not harmful to healthy trees.

These little fellows will eat the leaves of nearly a hunded of our native trees, so it's not surprising that they're chowing down on sweetgum, which is a choice of other caterpillars as well.

 

These are harmless insects. When they grow up, they will become beautiful white moths. Did you know that "White Moth" was Vladimir Putin's nickname when he was an intelligence agent? Secretive web-weavers.

 

 

 

 

 

Squirrel Damage

Last September we celebrated a healthy young sweetgum with a thorough blog post about its history and traits. You can find that post here. We noted a curious leaf-yellowing, but it was attributed to autumnal color change. Today, our sweetgum looks a lot different. The trunk has been thoroughly mutilated. Minor gashes appear along the trunk and large portions of bark have been completely removed. Although we did not catch them red-handed, squirrels are presumed to be responsible for the damage.

Suckering sweetgum trunk with minor wounds

 

Deep wounds open the tree to insect colonizers. Fresh green growth along the trunk suggests a will to live, and this sweetgum could perhaps survive long enough to successfully reproduce. However, for aesthetic reasons, our young sweetgum will most likely be removed in the near future.

 

 

Tree of the Week: Sweetgum (Liquidambar styraciflua)

Fall begins today with the autumnal equinox. As the photos below illustrate, the arboretum remains green―seasonal fall color and cool temperatures arrive late to northwest Louisiana. A close inspection of our tree of the week hints at seasonal change. This week we are examining the green leaves of a young, volunteer sweetgum (Liquidambar styraciflua).

The volunteer sweetgum germinated in the middle of a groundsel bush (Baccharis halimifolia), on a grassy, gradual slope near Cline Hall. In this photo, the groundsel conceals the sweetgum. Note the groundsel bush's gnarly, sprawling branches.

Another view reveals the slender, white trunk of the sweetgum, but its green leaves blend in with the surrounding vegetation.

Our volunteer was added to the catalogue in summer 2017. At that time, the tree was at minimum three years old. An exact age is unavailable.

Standing in its shade, we can appreciate the characteristic 'winged', or 'corky', bark of the young sweetgum.

Can you see the ridge along the branch?

The 'wings' can be flat, straight, wavy, and non-contiguous.

You might simply find bumps or notches along a branch rather than a ridge.

Although our young sweetgum is still green, on the first day of fall, the star-shaped leaves show signs of color change. But what is causing the yellow splotches? Is it simply seasonal color change, or could it possibly be a sign of deficient growing conditions resulting in chlorosis? We shall keep an eye on this individual and hope for dazzling autumnal colors.

Leaf blade and leafstalk each measure approximately 3¼ inches in length.

Leaf size varies. Here we have a bigger leaf with the same yellowish-green splotches.

Underneath, sweetgum leaves are pale green.

Sweetgum leaves have palmate venation.

Zooming in on the base of the leaf blade, we see brown fuzzy patches in between the veins.

Leaf margins are serrate.