Laurel Cherry (Prunus caroliniana)

 

Prunus is a famous, useful, and diverse genus. When you're "kind of a big deal," you typically have more problems come your way.

Here we see sap leaking from regularly-spaced wounds on the trunk of this laurel cherry (Prunus caroliniana).

This is likely the early stages of a condition arborists call "gummosis." The French botanist Auguste Trécul (1818-1896) was first to note, circa 1860, that a condition resulting in a superabundance of sap around a pathological zone could result from a variety of maladies. That name refers to the liquefaction of a tree's inner wood material and its leaking from wounds in the tree. This gummosis, or Gummibildung and even Gummifluss, as the Germans call it, can help protect a tree by isolating infected wood between hardened, protective plates. As it is really more of a physiological response than a disease itself, there is no singular cause of gummosis; it can result from insect damage, climatological stress, or infection by bacteria and fungi. 

Here we can see an old wound and the gummosis above it.

Back in June, this tree was placed on the docket for removal, primarily because of its significant lean. You can read that post here. The gummosis is not the reason for removal, but it did speed up the process. Enquiring minds want to know―what does the inner bark look like given the external gumminess? Is there a bug infestation or is it rotting? So the Faustian spirit urges, "Cut it down! Let's find out!"

 We are fortunate to have a volunteer ready to take its place. We'll stake that one and try to avoid the leaning tower of laurel.

In order to avoid destroying the smaller laurel cherry at the base, we first took out all the branches. Cutting most of the way through allowed us to extract the plant material slowly.

Here the tree has been separated into trunk and branches for easier disposal.

Here we can see the damage at the base of the trunk, which probably gave rise to the gummosis. Our working theory is that this damage was isolated and more-or-less healed by the tree. Later attacks by bugs or sapsuckers, in a vertical line from this damage, resulted in the tree leaking sap due to its proximity to the old wound.

The trunk ought to be round—and a crescent-shaped portion is clearly missing. What we don't see here is a lot of rotten material, a bug infestation, fungal infection, or other bad signs. The tree was, at least right now, apparently healthy despite the manifestation of gummosis. Nevertheless, we stand by the decision we made to cut it down, in large part due to the uncorrectable lean. In an unexpected turn, this newly cut lumber produced an aroma which corresponded precisely to a cherry soda.

All cleaned up and immediately replaced by the volunteer, who will reap great rewards in sunlight, nutrients, and water.

A Bacterial Gummosis of Cherries (1911) by F. L. Griffin

Gummosis of Prunus & Citrus (1911) by Ormond Butler

Laurel Cherry (Prunus caroliniana)

Last week on the blog we explained that, even though a tree looks pitiful and nearly dead, we shouldn't rush to cut it down and replace it. This week, we need to explain why a tree that looks beautifully green and productive needs to be cut down and replaced as soon as possible.  

 

A laurel cherry (Prunus caroliniana) is pictured center, completely blending in with its neighbors. On the right side of the frame, we see a non-decaying trunk of a deceased eastern red cedar (Juniperus virginiana) [read more about that individual here].

 

After removing the lower branches, we can now see the trunk of the laurel cherry. It is definitely leaning. 

It's leaning to the south. 

The southward leaning branches were heavy with leaves, and the fruits are numerous. 

Laurel cherry trees are handsome evergreen trees and the fruits ripen to blue. Keep in mind that this species is poisonous.

 

This is an interesting tree, and other than the lean, it appears to be healthy, so why cut it down? There are three reasons. First, the base of the trunk shows damage, which is a serious health concern. Second, there are several laurel cherry trees in the arboretum collection, and there are undocumented volunteers as well, so even if we cut this one tree down, the species will still have a strong presence in the arboretum. Finally, we have a young laurel cherry growing near the base of the trunk, so we can cut the big tree down and allow the young laurel cherry a chance to thrive. For these reasons, this richly green laurel cherry is on the docket for removal. 

 

In this photo, we see that the lower trunk of the laurel cherry is damaged. Also, on the left side of the frame, we can see the young laurel cherry ready to take its place. The young tree has grown up in 100% shade, so if we cut down the older tree all at once, it might be too much of a shock for the little one. So, for today, we started on the gradual process by removing all of the lower branches of the big tree. And in the following months we will steadily remove more branches, slowly exposing the smaller tree to more direct sunlight.

 

 

See previous posts on laurel cherry trees in 2023, and from early 2020 and late 2020.

 

Lady Bird Johnson page on Laurel Cherry 

USDA page on Laurel Cherry 

Rainy Day in Arboretum

It is a rainy day in the Centenary College arboretum, and we expect to have a rainy week ahead of us. So, what does that look like? If you are out for an exploratory walk, dressed in an appropriate slicker and boots, it can be quite agreeable to splash around in the puddles and listen to the flow of water and chirping birds. However, if your schedule doesn't allow for such leisure, the surroundings can feel quite dreary.

Below, we have a video that captures a look at water flowing through the arboretum. Centenary College does not have a flat campus; we have both gradual and steep slopes. On the western side of the arboretum, the slope is comparatively gradual, and in the video, we are standing towards the bottom of a hill where the water is collected in a narrow channel.

The laurel cherry (Prunus caroliniana) was selected as the focal point because last week we discussed this individual's small stature. We cannot say why it is so short. It grows in full sun, which might be too much sun, and sometimes it gets a lot of water, while at other times its location can be quite dry. As we see in the video, during rainy weather, a great deal of water flows past the laurel cherry. After the rain stops, this area might be wet for 24 hours and then quickly dry out, given hot weather conditions.

Tree of the Week: Laurel Cherry (Prunus caroliniana)

Toward the end of January, in northwest Louisiana, most of our deciduous trees have dropped their leaves. It's that time of year when the evergreen species are tasked with enlivening our oft-times dreary landscapes. In Louisiana, we are fortunate to have the laurel cherry (Prunus caroliniana).

 

In February of 2018, we collected four laurel cherry seedling volunteers from the lower pond and transplanted them to the south side of the arboretum. Today two (presumably the hardier specimens) remain. They are each appoximately 5 years old, but have reached considerably different sizes.

Pictured center, we see a laurel cherry. For comparison, a 6-foot ladder is standing next to it. This laurel cherry currently grows in full sun; however, for the first several years, this laurel cherry grew in the shade of an eastern red cedar. We removed that cedar in 2021. Today, the laurel cherry grows in full sun, toward the bottom of a gradual slope, a little up hill from the western flood plain.

 

Leaves are beautifully green in mid-January. No signs of reproduction on this young tree.

 

 

By contrast, this laurel cherry, also approximately 5 years of age, stands only about two and a half feet. Rather than developing a straight trunk, this laurel cherry is taking on the appearance of a small shrub, with four stems. We transplanted this young tree into full sun, where it has grown *up* in full sun, and when it rains, standing water is closer to its roots.

 

Springtime in the Arboretum

Spring is officially here, having begun on March 20th, and many of the inhabitants of the arboretum are in full vigor. A walk through will reveal a variety of species putting out new leaves, putting on flowers, performing reproduction, and otherwise enjoying the change in seasons.

These are samaras of the red maple (Acer rubrum).

Here we see flowers of the devilwood (Osmanthus americanus).

Laurel cherry (Prunus caroliniana) flowers are numerous!

These are purple pawpaw (Asimina triloba) flowers.

These are green pawpaw flowers. They will soon turn maroon or purple.

This pretty little white flower is produced by the mayhaw (Crataegus opaca). Last spring, an eastern red cedar was cut down in the hopes that we would see more of these flowers. As compared with the last three years, we are certainly seeing more mayhaw flowers today.

In northwest Louisiana, we love our azaleas, but not all azaleas are native to the southeastern United States. Here we have the stunning flowers of our native yellow-flowered azalea (Rhododendron austrinum).

 

 

 

Tree of the Week: Laurel Cherry (Prunus caroliniana)

Our tree of the week is one particular laurel cherry (Prunus caroliniana). Still in its youth, this specimen is about eight years old. You can read about its past on an old blog post, found here. Today we are marveling at a particular characteristic of the species, as exhibited by this individual. When the top of the main trunk is broken, a new one will sprout.

Upon its planting two years ago, this tree had a straight trunk. It grew steadily in its new location. Unfortunately, earlier this year, a falling branch snapped off nearly a foot of new growth. There was nothing to do but clean up the wound (snip-snip) and simply wait to see how the tree would respond to losing its top.

This past week, we got our response. The laurel cherry sent out a new shoot at the top, right where the repair was made. Not all trees are capable of this, and age certainly plays a role in a tree's ability to resprout. However, in the arboretum, the laurel cherry has a reputation for this behavior: you can read about it in a discussion of this individual's presumed parent, found here.

Mid-March Spring Time Flowers

Puffs of white flowers cover the slender branches of the laurel cherry (Prunus caroliniana).

Wild geranium (Geranium maculatum) flowers are light pink and low to the ground. They are growing well with blue phlox, Christmas fern, and a young red buckeye.

Walking through campus you will see that some azaleas are already in full swing. Our yellow-flowered azalea shrubs (Rhododendron austrinum) are preparing for a dazzling display this coming week. They are called 'yellow-flowered'; however, in the ground of the arboretum, they are 'orange-flowered' and produce a delightful aroma. Don't miss it!

Tree of the Week: Laurel Cherry (Prunus caroliniana)

Our senior laurel cherry (Prunus caroliniana) is pictured center. This same tree was featured two years ago at this time of the year. You can read about it here. At that time, it was the sole laurel cherry in the collection. Over the past two years, we added seven more. All new additions are volunteers found growing in the ground of the arboretum. It is quite probable that these volunteers were born from the fruits of the senior individual. This week, we'll look at pictures of those fruits.

Looking up, we can see more than a few of the black fruits mixed in with the evergreen leaves.

Up close, the fruits are dark blue, almost black.

Developing flowers can also be found this week.

The round (poisonous!) fruits are a ½ inch in diameter.

These fruits are drupes: each fruit is composed of a leathery skin, a juicy inner layer, and one large, tough seed. If you have a notion to grow your own laurel cherry, pick a few and take them home for a germination project. But keep in mind that the literature roundly agrees that these fruits are poisonous!

Laurel Cherry Flower Buds

In late January, large flower buds can be found on the old laurel cherry (Prunus caroliniana). This specimen is discussed at length here.

These photos were taken January 26, 2019.

Tree of the Week: Laurel Cherry (Prunus caroliniana)

Today, we welcomed a new member into the arboretum collection: a laurel cherry (Prunus caroliniana). This specimen had its beginning in the arboretum. In the fall of 2013, it was found growing along the brick retaining-wall west of Hamilton Hall. At the time, the little laurel cherry was only a very small seedling, so transplanting it to a plastic container was easy. For the past five years it has been living in a series of progressively larger containers, nurtured by the current arboretum curator. Today it was transplanted back into the arboretum.

Measuring from the base of the trunk, this laurel cherry is 4 feet, 8 inches tall.

The container is less than a foot in diameter.

The container is less than 9 inches tall.  Not much digging is needed.

Not much information is available on the laurel cherry, even from the best sources. Some describe it as preferring upland sites, some postulate lowlands. Some sources say it will tolerate anything from full sun to full shade. In the arboretum, we have recently noticed a cluster of volunteer laurel cherries that are doing quite well in full shade. Consequently, we have selected a shady spot for this specimen. In the summer this area is heavily shaded by a large Nuttall oak (Quercus texana) and a large pumpkin ash (Fraxinus profunda).

The laurel cherry will be growing at the bottom of a slope, on the west side of the stream.

After the location was chosen, it took no time to dig a hole.

This part of the arboretum has rich black dirt. It was so easy to dig in this spot that the digger got carried away and the hole turned out to be too deep.

The new addition to the arboretum fits naturally into the landscape. It perhaps blends in too much, which means that we will need to put stakes or big rocks around it to save it from the mowers this summer.

Tree of the Week: Laurel Cherry (Prunus caroliniana)

Our tree of the week is an evergreen specimen. The laurel cherry (Prunus caroliniana) is a small tree native to Louisiana and found scattered elsewhere throughout the Deep South. As we are nearing the end of January, the laurel cherry holds onto its dark green foliage.

There is a lone laurel cherry in the arboretum collection. It was collected locally from the Broadmoor neighborhood of Shreveport. It was planted in October 1990, making it nearly 30 years old. During its early years, the tree grew with a significant crook in its trunk, resulting in lopsided growth. Luckily, a vertical shoot emerged from the crooked trunk and the lopsided growth was later pruned away. Today we have a fairly erect laurel cherry tree with an interesting trunk.   

The photos below were taken on a partly cloudy, mild January day.

This laurel cherry is located on a gradual clay slope between Hamilton Hall (pictured) and the Student Union Building. A mature Shumard oak (Quercus shumardii) partially shades the area.

Another view reveals a slight bend in the trunk.

Laurel cherry trees have simple, elliptic, alternate leaves.

The leaf margins are slightly serrated on some of the leaves.

Laurel cherry trees have dark green leaves, even in the middle of winter. This particular leaf has smooth, wavy margins. It measures to just over 3 inches in length.

Underneath, the smooth leaf is light green. This particular leaf has serrated margins and measures 2.5 inches long. The red petiole is also noticeable in this picture.

Life hasn't been all peaches and cream for this laurel cherry. The remnants of the original, crooked trunk can be seen here.

This is the smooth grey bark from the younger portion of the trunk.

Here we have the old, rough and gnarled portion of the trunk.

The dark grey trunk shows a lot of 'character', but remains small, despite being nearly 30 years old.

You can see older pictures of this laurel cherry here.

For more information about this native tree consult the following:
United States Department of Agriculture
Louisiana Plant Identification and Interactive Virtual Tours (LSU AgCenter)
Texas A&M University -- Native Plants Database
University of Florida IFAS Extension