Toothache Tree (Zanthoxylum clava-herculis) and Giant Swallowtail (Papilio cresphontes)

Over the past several years, the number of individual toothache trees in the arboretum has steadily increased. The mature tree at the southwest corner of Mickle Hall continues to produce an abundance of fruit, and little volunteers continue to pop up each year. We have allowed the young trees to continue growing, even in locations that are unsuitable in the long-term. For instance, despite there being no future in the aboretum for a volunteer growing next to the trunk of a large mature tree, their leaves can provide food for a very interesting caterpillar. 

Giant swallowtail (Papilio cresphontes) caterpillars have recently been spotted nibbling away on the leaves of a 4-year-old toothache tree (Zanthoxylum clava-herculis). Two caterpillars are captured in this photo. Do you see them?

Here we have another caterpillar, stuck to the spiny, slender trunk of the toothache tree.

They are funny looking creatures. You may even find their heterogenous and mottled appearance disgusting. They are camouflaged to resemble bird droppings! What wonderful diversity occurs in the natural world. And these critters are certainly thorough in their work of stripping the toothache tree of its foliage.

Rather than allowing the horde of caterpillars to defoliate a single tree, we remove a few individuals and place them on the volunteer toothache trees. As noted above, those trees that haven't been added to the catalogue because, based on their current location, they do not have a future in the arboretum.

We certainly want to make sure the caterpillars are well-fed--they turn into such lovely butterflies! Can you think of a better candidate for the "ugly duckling" of butterflies?

Tree of the Week: Toothache Tree (Zanthoxylum clava-herculis)

Autumnal weather has arrived in northwest Louisiana. This week we experienced low temperatures in the 30s, and over the next several days we expect high temperatures above 80℉. Although the mosquitoes are still buzzing about, the overall drop in temperature means that we can start moving plants around without fretting too much about survival rate. Today, a young, volunteer toothache tree (Zanthoxylum clava-herculis) was transplanted to a better location and officially added to the arboretum catalogue. 

  

The volunteer toothache tree is pictured center. Some time within the past few years it germinated in the patch of dewberry (Rubus trivialis) on the west side of Mickle Hall, not far from the mature toothache tree. After the dewberry and yellow passion flower vines were pulled away from it, we could see the form of the young toothache tree: it is a little less than 2 feet tall, and it has a very long surface root.

 

This is a detail image of the toothache tree's long surface root. The little tree isn't connected to the soil at the base of its trunk, and it seems that the vines that had grown up around it were doing much of the work of holding it up straight.

 

Examining the volunteer toothache tree gave us another look at the giant swallowtail caterpillar (Papilio cresphontes). We talked about this species on our previous blog post.

 

 In this video we can see the caterpillar eating part of a toothache leaf. (The video also shows how windy it was today!) When humans chew on the leaves of this tree, we experience a tingling sensation in the mouth, and if we chew on enough of the leaves, we experience a numbing effect.

 

This large, chunky caterpillar with a very interesting color scheme was relocated to the nearby mature toothache tree.

 

This toothache tree only has shallow roots, with one particularly long surface root. Not much digging was required to remove the tree from the dewberry patch.

The root system is surprisingly sparse, especially considering how healthy the trunk looks.

 

The toothache tree was transplanted from the top of a hill to the bottom of a hill in the hopes that it will have access to more water. It appears to be all by its lonesome on the Fitness Center lawn. A black oak (Quercus velutina) and black willow (Salix nigra) are growing nearby.

 

Two metal stakes flagged with pink tape serve as protection against lawn mower damage, and the pine straw mulch will help the soil retain moisture. This individual was thoroughly watered after planting was complete, and the soil moisture will need to be monitored until the tree enters dormancy.

 

Leaves at the very top already started to droop from the stress of relocation. They will hopefully perk back up soon. This same thing happened to the two other toothache trees that were transplanted this past spring. You can read about them here. Both of those young trees survived the summer.

 

 

Giant Swallowtail (Papilio cresphontes)

At the southwest corner of Mickle Hall, our toothache tree (Zanthoxylum clava-herculis), is currently playing host to an interesting guest.

 

The guest has such intriguing camouflage. It's pictured center. Can you see it?

 

This is the caterpillar Papilio cresphontes. Does it resemble a tree lichen or something that a bird (or lizard) might have left behind? Either way, the bulbous shape and color combination allows this individual to blend in with its surroundings. It's a startlingly effective natural camouflage!

This individual measures 2 inches long. It vigorously scooted away as soon as I put it down. No threatening red 'tongue' was revealed during this encounter. After the brief photoshoot, the caterpillar was returned to the toothache tree to continue its snacking.

The caterpillar was originally found here, on this little toothache tree, which was planted in the arboretum this past spring. There were two caterpillars found on this small, young tree, and they were allowed to stay for several days since they didn't appear to have particularly large appetites and it's about time for our deciduous trees to drop their leaves. While on this little toothache, the caterpillars revealed their famous red 'tongues.'

After the two caterpillars nearly stripped all of the upper leaflets, it was time for them to be relocated. Both caterpillars were placed on the mature toothache tree at the southwest corner of Mickle Hall. Only one of which was later found for this photo blog. We hope the other one found a safe place for its next stage of development.

Southwest Corner of Mickle Hall

Architectural plans for the renovation of the Centenary College science building, Mickle Hall, include an addition to its west side. The building project necessitates the removal of a significant number of specimens from the arboretum catalogue. A small number of individuals can be transplanted; that work has already begun (see here). Unfortunately, most of the trees will perish in the name of progress, as they are too large and too old to relocate. In this post we will continue to document the appearance of the arboretum before the renovations change its layout. Below, we take a look at one of the groupings of plants.

Here we see the southwest corner of Mickle Hall. In early January 2022, a mature post oak (Quercus stellata), in declining health, was removed from this location. It stood to the right of the entrance. During the course of the proposed renovation, we will see the removal of the grouping of plants to the left of the entrance.

All of these plants will be removed. Within the leaf litter, there are several seedlings that could be collected and potted for future plantings within the arboretum, but all of the larger plants will be cut down and/or torn up with machinery.

In this photograph, we see the arboretum shed on the far left. It will also be removed, as Mickle Hall is expected to expand into this area.

The largest individual in this grouping is a toothache tree (Zanthoxylum clava-herculis). We have discussed this individual on previous blog posts, found here. It is very tall and over 15 years old. With the proposed addition to Mickle, it will die. However, looking on the 'sunny side of life', we must note that two seedlings were identified in the leaf litter yesterday, and two young toothache trees have already been transplanted elsewhere (read here).

This toothache tree has grown tall, but the curves in its trunk do not inspire confidence in its longevity, so perhaps we ought not be too upset about its destruction. Furthermore, this photo is a reminder that we ought to carefully stake young trees to encourage good upward growth.

This imperiled individual certainly can boast of having a unique trunk, with all of its bumps and spines. It will take some time for the young toothache trees to develop such interesting bark.

Here we see the reproductive structure of the toothache tree. You can find pictures of mature fruits on an older blog post, found here. Fruits from this toothache tree have successfully germinated in the soil of the arboretum, and, depending on the construction schedule, the developing fruits pictured here might have time to ripen and then potentially germinate.

A French mulberry (Callicarpa americana) grows directly next to the toothache tree, and a coral bean (Erythrina herbacea) grows on the other side of the French mulberry. Given its size and this species' tendency to resprout, the French mulberry could perhaps be successfully transplanted. However, the arboretum collection would best be served by focusing on nurturing the numerous seedlings that this individual has produced. Back in February, we collected five seedlings from this corner and transplanted them to other locations in the arboretum. More French mulberry seedlings remain in the leaf litter.

This French mulberry leaf is 5 inches long. It is floppy, fuzzy and very fragrant. Crush one and think about what you can detect. Some say that the strong fragrance serves as a natural mosquito repellent! 

Underneath, white hairs are visible on the French mulberry leaf.

 

Our greatest loss from this grouping of plants will be the coral bean (Erythrina herbacea). Over the winter, the root structure of this plant was examined, and it looked like it would take a backhoe to pull it up out of the ground―the trunk was large and bulbous. This plant is more than 10 years old and looks stuck in its place. It's unfortunate to lose this plant because it is a very handsome specimen, and, at this moment, it appears to be the only coral bean currently in the collection. There is one more coral bean, but it has not yet put up new leaves this spring.

 

Coral bean leaves are compound: this is one leaf with three leaflets. This leaf measures 7½ inches long.

 

Underneath, leaflets are a lighter shade of green. How would you describe the shape of the leaflet? Spade-shaped?

 

A black cherry (Prunus serotina) and its accompanying Carolina moonseed (Cocculus carolinus) must also be removed according to proposed plans. The black cherry was planted here in April 2019. You can read about its history on an old blog post found here. Pieces of Carolina moonseed resided in this sunny location prior to that time.

 

Taking a closer look at the black cherry, we see an irregular trunk. The trunk has the characteristic handsome bark, but the trunk is curved and divided. It never developed a straight form, turning into more of a shrub than a tree. So, it won't be sad to depart with this individual, especially since black cherry seedlings are commonly found in the leaf litter of the arboretum.

Caronlina moonseed is weedy in the arboretum. There are plenty of locations with Carolina moonseed, but there are few places where we would want to actually encourage it to grow. So, it might be a little challenging to find a new spot for our sign.

Carolina moonseed leaves are neat! Do you see an elephant's head pictured here? Two big ears and a trunk?

Interestingly, Carolina moonseed leaves resemble coral bean leaflets. On the left, we see a coral bean leaflet. On the right, we see a Carolina moonseed leaf. There are two different shades of green, but both the leaf and the leaflet have the shape of an elephant's head.

Underneath, the coloration is similar as well. Holding them in your hand, you can quickly tell them apart. The coral bean (pictured left) feels very delicate this time of year, as if it would easily tear or crumple. By comparison, the Carolina moonseed leaf (pictured right) is rigid. Also, underneath, the Carolina moonseed leaf has fine white hairs and feels soft to the touch.

 

Within this grouping of plants, five individuals are expected to be removed for construction and renovation on Mickle Hall. This is only one of several groupings that are imperiled by the proposed plans.

 

Tree of the Week: Toothache Tree (Zanthoxylum clava-herculis)

Our early springtime weather has made tree planting an extra special joy. It's much more agreeable to dig in the dirt when it's 70 degrees and sunny, rather than 40 degrees and overcast. However, the trees planted this time of year are at a disadvantage. It would be best to allow the roots time to settle into their new soil and maybe start putting out new roots before spring weather arrives. Instead, as we see in the below photos, trees are already 'waking up' and rapidly expending their stored energy to make leaves, and it is surely traumatic to the organism to be uprooted at this time, as the root system is inevitably damaged during the moving process. So, for the good of the tree or shrub, those dreary January days in northwest Louisiana are best for transplanting because we cannot count on the plants to be dormant through February. 

Now, let's be hopeful! Below, we have pictures of two recently transplanted toothache trees (Zanthoxylum clava-herculis). We collected both near the southwest corner of Mickle Hall, growing next to each other in a dewberry patch. One of the toothache trees is already in the arboretum catalogue; we discussed it in a previous blog post, found here. The other toothache marks a new entry into the arboretum catalogue. We relocated both trees to avoid certain death from planned construction work, but, in truth, the trees themselves did not choose a very good spot for germination—that dewberry patch at the top of a hill was much too dry. Now, the young toothache trees are growing in wetter conditions.

This young toothache tree volunteered in the arboretum near the southwest corner of Mickle Hall. We don't know exactly when it germinated, but it must be less than three years old. Today, it is 18 inches tall. It is now growing in a partly sunny location, along the arboretum drainage channel, near the large Louisiana palmettos.

The leaves appear to be drooping a little after the move. Interestingly, both toothache trees had shallow roots; there wasn't a difficult taproot to dig up.

The other toothache tree is considerably taller, measuring 4 feet and 11 inches. This specimen entered the arboretum catalogue in December 2020. At that time, it measured less than 3 feet. It is now growing in full sun along the western drainage channel, near a salt matrimony vine (Lycium carolinianum) and a swamp dogwood (Cornus foemina).

Unfriendly spines cover the thin trunk. Heavy gloves and caution are recommended for working with toothache trees.

The leaves are also prickly! Handle with care!

Tree of the Week: Toothache Tree (Zanthoxylum clava-herculis)

 

Our tree of the week is the toothache tree (Zanthoxylum clava-herculis). At the beginning of August, this species still has its dark green foliage and its fruits are ripening.

 

All pictures, above and below, are of a single toothache tree, located at the southwest corner of Mickle Hall. This tree has previously appeared on the blog; you can find that post here.

 

The red bricks provide a nice backdrop for the green foliage and fruit clusters.

Toothache trees have compound leaves. This leaf measures 10 inches in length, and we count 9 leaflets.

 

It looks like the leaflets have experienced some predation; someone must find them tasty.

Leaflets have pointed tips, toothed edges and asymmetrical bases. Also, note the waviness.

 

These leaflets measure less than 4 inches.

 

The fruiting clusters are colorul this time of year. The panicles are bright red; the unripe capsules are light green; and the ripe fruit is nearly black.

 

Ripe, black fruits protrude from darkening husks. These are seeds. Feel free to collect a handful and start your own germination project! But watch out for the spines....

 

Individual fruits are very small.

It's claimed that these black orbs are tasty treats for birds, so you will need to be quick if you are interested in growing your own toothache tree.