Loblolly Pine (Pinus taeda)

A young pine tree in the arboretum is now in need of a sign. Due to uncertainty about its species, we have delayed creating an official arboretum placard. To see the post from March 2023, when this specimen entered the arboretum collection, click here. 

Upon collection from the wild in a wooded area north of Shreveport, the tree was so young and small that it lacked obvious species-defining features. It just looked like "native pine." Rather than risking misidentification, which can be a more-or-less permanent issue, we left its classification an open question and waited...for years.

In spring 2026, our young "native pine" is looking more grown-up! 

This fine specimen grows on the grassy slope north of Cline Hall, an area that is open and sunny, but is steadily planted with young trees.

We can confidently identify this specimen using photos of its needles and flowers, its male cones. It's a loblolly (Pinus taeda). No surprises here! In our region, this is a default and commonplace pine, especially dominant in forestry. Its lumber is often sold as SYP (Southern Yellow Pine) and its binomial name Pinus taeda is a Latin-Greek mashup that could be translated as 'Pine-pine' or 'Resinous Resin-tree.' This name doubles-down, to an unusual degree, on the piney-ness of this tree.

This tree is developing a proper and upright growth pattern due to its generous allotment of sunlight and favorable position. Young trees in the wild will be spindly due to the "battle of the understory" that most of them undergo.

Here's the source of that delightful yellow dust covering your car, your outdoor furniture, your pets, etc. Achoooooo!

The identifying features that the juvenile tree lacked: fully-developed needles and reproductive structures. This is the first year that we have seen flowers on the tree, and not many are present. 

 

The fully-developed needle clusters come in trios and are around 6-7 inches long. A shortleaf pine would have needles half that length and usually come in twos. Longleaf pine needles come in threes, but would generally start at 8" in length.

 

The pollen cones are yellow, banana-shaped and approximately an inch in length. Longleaf pollen cones are a startling blue-purple or an orange-red. Shortleaf cones are similar in color and shape to loblolly, but tend to be only half-an-inch or a little larger.

 

There are several on-site native mature loblolly pines in the arboretum and on the campus as a whole, so we might argue that the arboretum doesn't need 'just one more loblolly....' However, the campus loses at least one mature loblolly each year, so it's important to continually replace those old pines. And, it's super neat to see the different stages of a tree's development because as they age, loblolly pines lose those lower branches and we only see that beautiful brown, seemingly perfectly round trunk. So, we are happy to have this young loblolly on that grassy slope in front of Cline.

 

For further online reading, please consult the following websites: 

NC State Extension page on Loblolly Pine 

Article on Loblolly from "The Tree and Its Environment" (1990) 

Ladybird Johnson Wildflower Center page on Loblolly 

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?

March Blooms in the Arboretum

Spring doesn't officially begin until the vernal equinox, which is still about two weeks away. But the weather, the animals, and the plants have decided that, for us in Shreveport, the season has arrived in advance of its astronomical formalities. 

Glorious flowering from our Mexican plums (Prunus mexicana) this week.

 

At this time, the flowers have a powerful, distinct, and not altogether pleasant aroma.  Nature's a funny thing.

Here we have a post from March 2019 featuring the same delightful Mexican plum blossoms. And a post from this time last year showing our efforts to transplant some new Mexican plums. Leafing-out season will tell us if that was successful.

Elsewhere in the arboretum, you can find flowers of the paw paw (Asimina triloba). These are less-showy. You will need to go looking for these along the drainage channel that runs north to south through the arboretum.

The juxtaposition of these deep crimson-purple bells alongside the green bells is unforgettable.

We attempted some cross-pollination. Good luck, little tree.

See our post from last summer on planting new paw paw and a similar springtime post from 2022 that features paw paw flowers.

Mexican Plum (Prunus mexicana)

We've added another Mexican plum (Prunus mexicana) to the arboretum catalogue. This species is a fan favorite, producing delectable and highly-colored fruits that make a complete mess during their season. Squirrels eat them; bugs eat them; we eat them. Raccoons and possums eat them after hours when nobody is looking. The mature trees produce so much fruit that it simply lays about on the ground. This time of year, if you look under any of those trees, you will find seedlings. The individual pictured below is one such seedling.

Last April, this young tree was collected from under the mature Mexican plum growing on the steep slope near Mickle Hall (see here). It survived transplanting and the long hot summer months thanks to an onerous watering regime. Today, it is almost a foot tall.

Since the fresh green leaves developed in full sun, we don't need to worry about shocking it with too much sunlight when we plant it.

We planted it in full sun near the top of a gradual slope on the north side of the Cline Hall dormitory. This is an open, grassy area, and this time of year we allow the wildflowers to grow tall. The stakes with pink tape are necessary for calling attention to our small tree—we don't want it to be stepped on, stomped flat, or mowed over.

Red Buckeye (Aesculus pavia)

On October 25, 2023, first-year students collected and planted seeds from red buckeyes in the arboretum. Approximately a month later, seedlings emerged from the dirt. Now, 16 months later, we see the first flowers! That's fast development.

Professor Rachel Johnson brought two groups of students to the arboretum for tours. The first group was from an 8 a.m. class. Students picked up 5 seeds and planted them in this spot, marked by the metal tag.

At minimum, three of the five seeds germinated. One plant remains, and it is short and wide, and it has one red panicle. 

This is full sun. Online literature says that red buckeyes can grow in full sun or shade, so this is one of our experimental spots for full sun conditions. The majority of our other buckeyes grow in part or full shade.

Students from Professor Johnson's noon class also planted 5 seeds. They were slower to germinate by just a week or two. Several seedlings emerged, and died back, and started again.

Today, we see two little plants. One is significantly larger than the other and it has one red panicle.

The arboretum has a steadily growing collection of red buckeyes. We are really hoping to draw in the ruby-throated hummingbirds with these clusters of pretty red flowers.

You can read more about the germination project on an earlier post, found here.

 

Winged Elm (Ulmus alata)

Today we added a young winged elm (Ulmus alata) to the arboretum collection. This species grows abundantly in Caddo Parish—it is very 'weedy'. There are three mature winged elms in the arboretum: one is an on-site native; one was intentionally collected from Walter B. Jacobs Nature Park in Caddo Parish; and one is a volunteer. Our new recruit was planted in full sun near Mickle Hall, and it is expected to flourish with very little maintenance.

This specimen was collected in Caddo Parish, just north of Shreveport. Discovered in 2023, after it had germinated in a pot of soil meant for another plant, it now enters the Centenary campus as a 2-year-old, measuring 18 inches tall.

Our little tree has already leafed-out. We see serrate leaf margins.

And looking closer, we see a slight ridge along the stem. This young tree is developing its corky 'wings', which help us identify this tree as a 'winged' elm. Sweet gum trees (Liquidambar styraciflua) also have this characteristic.

 

 

US Forest Service Ulmus alata Fact Sheet 

Shortleaf Pine (Pinus echinata)

 

There is one shortleaf pine (Pinus echinata) in the arboretum collection. It is approximately 30 years old. In October 1997, two trees were purchased from Coyote Creek Nursery in southeast Louisiana. The following month, they were planted near the Student Union Building. Today, one tree remains.

The shortleaf pine is pictured center. It grows next to the sidewalk that runs between the Student Union Building and Cline Hall Dormitory.

The thin, flat plates on the trunk have a reddish tint.

And here we see the work of the yellow-bellied sap sucker (Sphyrapicus varius). There is a fairly straight, diagonal line of holes drilled across the trunk. At least the holes aren't actively weeping.

All of the limbs on the west side of the trunk have detached and falled off, presumably because they were heavily shaded by the nearby water oak (Quercus  nigra). The remaining lower limbs hang toward the open sidewalk, in full sun. 

Luckily this tree still has lower branches so that we can examine fresh spring-time twigs. Here we see reproductive activity. Shortleaf pines are monoecious, which means they have both male and female parts on the same tree. In this photo, we see a cluster of the pollen-producing catkins, and they are not open yet.

This twig was snipped without the aid of a ladder.

Shortleaf can be identified by the "short" needles that typically come in duos.

These needles measure less than 3 inches. By comparison, our loblolly (Pinus taeda) needles measure 7 inches long, and loblolly pines have three needles per bundle. 

Needles were removed so we could examine the catkins. According to Dr. Becky Barlow at Auburn University, catkins form in the spring while cones develop a few months later, higher in the tree. Catkins are a yearly product, while cones take two years to develop. A healthy, mature tree will therefore have staggered cohorts of pollen and cones.

At the current time, the catkins measure less than half an inch long. They will grow larger before releasing pollen.

USDA NRCS page on Shortleaf Pine

USDA Forest Service Southern Research documentation 

NC State University Gardener Page on Shortleaf Pine

The Shortleaf Pine Initiative

Trillium recurvatum

Trillium-time is upon us! This beautiful and uncommon group of plants is perennially interesting and compelling, so let's take a moment to chronicle their brief flowering season. 

As documented previously, the arboretum is home to two species of trillium: Trillium gracile and Trillium recurvatum. In this series of photographs, we are focusing on Trillium recurvatum. The Key to Trillium, provided by the North Carolina Botanical Garden, helps to confirm that the species pictured below is indeed Trillium recurvatum.

In this photo, we see two individual trillium plants. A tall stalk supports a little burgundy flower that has three large mottled green leaves.

Do you see the three wine-colored petals that are standing upwards and meeting? This helps us identify our plant as Trillium recurvatum.

This plant is less than a foot high, approximately 10 inches above the ground.

One petal and two filaments were removed to get a better look at the reproductive parts.

The green sepals curve down, between the mottled green leaves (bracts). These sepals touch the stalk (scape).

There are six filaments. The anther connectives are curved inward.

Filaments are more than ¼ inch in length. The flower does not smell bad; there is a faintly pleasant smell, nothing offensive. Following the Key to Trillium, we can conclude that this is definitely Trillium recurvatum.

Phlox in Bloom (Phlox divaricata)

 

This bed of phlox is a perennial (pardon the pun) favorite among the arboretum's guests. Your curator has noticed more than one group using this delightful splash of delicate blue-purple color as a backdrop for photographs.

These gorgeous wildflowers are sure to improve the mood of anyone who can spare a moment.

The patch of phlox has significantly grown over the past several years. This photo, from 2019, shows how the phlox was neatly contained within a flower bed lined with bricks. Today, the bricks are still there, demarcating the bed, but a reduction in spring-time mowing has allowed for this wildflower to naturally spread.