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

The toothache tree (Zanthoxylum clava-herculis) is known for its peculiar bark. Medicinal use of the inner bark is the origin of the common name 'toothache tree': chewing the inner bark numbs the gums, relieving the pain associated with a toothache. The outer bark of this tree has resulted in another common name: Hercules' club. The whole tree is covered in spines, but the trunk of the tree and its older branches have large thorns, giving the trunk and branches a particularly aggressive appearance, recalling the deadly weapon used by the Greek hero Heracles.

There are three individual toothache trees in the arboretum collection, all growing at the southwest corner of Mickle Hall. Two of the three trees were purchased from Woodlanders Nursery out of Aiken, South Carolina. They were planted in 1989. More than a decade later, Ed Leuck added an additional specimen, collected in Shreveport, from along Clyde Fant Parkway. Interestingly, the younger tree has significantly outpaced the two trees from South Carolina. The specimen from Shreveport is over twice the size of the 1989 plantings.

This is the southwest corner of Mickle Hall, the entrance to the basement of the building. The youngest toothache tree is almost two stories tall, reaching the first floor windows. French mulberry (Callicarpa americana) and coral bean (Erythrina herbacea) grow in its shade. The older two toothache trees are nearby (not pictured), and half the size of the younger tree.

Trunk detail: mottled bark with thorn-tipped corky knobs

Bark detail

Branch with thorns in profile; branchlet also showing thorns

Cluster of unripe fruit

Zanthoxylum clava-herculis leaf detail

You can see additional photos of the arboretum's toothache trees here.

For more information about this species consult the following:
United States Department of Agriculture 
Louisiana Plant Identification and Interactive Virtual Tours (LSU AgCenter) 
Texas A&M Forest Service

Tree of the Week: Parsley Hawthorn (Crataegus marshallii) VOLUME II

Not long ago we reviewed the yearly progress of an idiosyncratic native tree. The parsley hawthorn has interesting leaves, beautiful bark, and a noteworthy (bad) smell! Crataegus marshallii is especially important to the arboretum because it is found in healthy, stable populations in Caddo Parish's wild places. This week we're taking a second look at the arboretum's specimens and focusing on the bark.

Most of the year this tree has a beautiful, handsome, mottled bark. During high Spring, a change comes over specimens of this species that are still actively growing. Old bark is sloughed off, and fresh bark is revealed. Both the inside of the old bark and the outside of the new bark are a rich, velvety orange. Catch it while you can! As the new bark ages, it loses the orange color and takes on the familiar mottling of grey, brown, and green. Enjoy the photos below!