Guaiacum coulteri

A couple of announcements before today’s entry: first of all, welcome to Ruth Sanborn, who will be sharing both her photographs and writings with us on Botany Photo of the Day. We’ll get a short bio from Ruth in the near future.

Secondly, for local readers, don’t forget the Indoor Plant Sale tomorrow and Friday here at the garden!

Ruth is responsible for today’s write-up:

Guaiacum coulteri, an endemic Mexican tree species, is the victim of extensive logging in Mexico. Commonly known as the soap bush, Guaiacum coulteri is a relative of the more commonly known creosote bush, Larrea tridentata of arid southwest North America. Both are members of the Zygophyllaceae. Soap bush’s distribution ranges 1,500 km along the western edge of mainland Mexico from southern Sonora to northern Oaxaca. Excessive felling of canopy trees for export quality lumber since 1914 has altered the population structure to understory shrubs, and has also left the population with a patchy distribution. The tree is currently being evaluated for endangered species status on the IUCN Red List (see: Gordon, JE et al. 2005. Guaiacum coulteri: an over-logged dry forest tree of Oaxaca, Mexico. Oryx. 39: 82-85).

This small tree has ornamental value boasting gorgeous sapphire blooms from May to September. It grows to a height of 2-8m (6-25 feet) and can thrive in partial shade to full sun. The water requirements are less clear, as some sources call it a xeriscape specimen while others recommend wet soil. Its native range in Mexico receives between 30 and 100cm (12 to 40 inches) of annual rainfall.

We would like to sincerely thank DarinAZ of the UBC Botanical Garden forums (from Phoenix, Arizona) for posting this exquisite photograph in this thread via the Botany Photo of the Day Submissions Forum.

Guaiacum coulteri

9 responses to “Guaiacum coulteri”

  1. Karen Vaughan

    Guaiacum bark infusion is traditionally used for the treatment of syphilis. It has been used more recently in the herbal treatment of Lyme disease, along with other antimicrobial and alterative herbs, and antibiotics as well.

  2. elizabeth a airhart

    welcome ruth and thank you

  3. Scott McGillivray

    beautiful flower….lovely….thanks…

  4. sheila

    so gorgeous. i think this also smells faintly like rain.

  5. Helena

    Is this available in the lower Mainland?
    Sure is beautiful.

  6. Josh Williams

    The wood of Guaiacum species is better known as “lignum vitae” or simply “ironwood.”
    The heartwood is impregnated with heavy, oily resin. It sinks in water, (specific gravity = 1.28), hence the name ironwood. These days It’s mostly used for carvings and turnery – small decorative items.
    Until about the 1920’s, the stuff was invaluable for it’s use as shaft bearings and journal bearings, the wood was know for being “self lubricating.” Bearings in windmills and water wheels, wooden pulleys, propeller shaft bearings, were traditionally made of lignum vitae. There was a huge demand for it. As far as I know, it’s possible to grow guaiacan in plantations, but costly and difficult. It grows very slowly. Unfortunately, much of what is sold commercially still comes from virgin forests. The bark and resin have quite a few medicinal uses, I’ve heard.

  7. Mary Miller

    Lignum vitae is fast beoming a popular landscape tree in South Florida. They are relatively expensive – especially when full grown – due to their slow growth (compared to Ficus and other tropicals). If you ever get to the Florida Keys there is a real treat down near Key West.
    ” . . .Lignumvitae Key Botanical State Park
    The virgin tropical hardwood hammock that thrives on this island was once common on most of Florida’s Upper Keys; most of these forests have been lost to development on other islands. In 1919, William J. Matheson, a wealthy Miami chemist, bought this tiny island and built a caretaker’s home with a windmill for electricity and a cistern for rainwater. Today, his hideaway is the visitor center for this island forest. Ranger-guided tours are given twice daily, Thursday through Monday. The park is accessible only by private boat or tour boat.”
    Fairchild Tropical Botanic Garden also has a number of beautiful specimens.

  8. Annie G.

    I remember Merlin’s wand was supposed to have been made of lignum vitae (“the wood of life”) in T.H. White’s THE ONCE AND FUTURE KING. I understand clockmakers often used it because of the self-lubricating Josh Williams mentioned.

  9. Rusty

    Cool leaves! How would you describe the structure of them if you were a taxonomist?

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