Guaiacum coulteri

Family: Zygophyllaceae
Genus: Guaiacum (GWY-uh-kum) (Info)
Species: coulteri (kol-TER-ee-eye) (Info)
Synonym:Guaiacum planchoni




Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun

Sun to Partial Shade



Foliage Color:

Unknown - Tell us


6-8 ft. (1.8-2.4 m)

8-10 ft. (2.4-3 m)

10-12 ft. (3-3.6 m)


4-6 ft. (1.2-1.8 m)

6-8 ft. (1.8-2.4 m)

8-10 ft. (2.4-3 m)


USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

Where to Grow:

Unknown - Tell us


Unknown - Tell us

Bloom Color:


Medium Purple

Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Late Summer/Early Fall

Other details:

Unknown - Tell us

Soil pH requirements:

Unknown - Tell us

Patent Information:


Propagation Methods:

From woody stem cuttings

From seed; germinate in vitro in gelatin, agar or other medium

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds


This plant has been said to grow in the following regions:

Phoenix, Arizona (3 reports)

Tucson, Arizona (2 reports)

Palm Desert, California

Vista, California

Galveston, Texas

Gardeners' Notes:


On Jun 13, 2018, gatobut from Palm Desert, CA (Zone 9b) wrote:

Tohono Chul Gardens sent me a one-gallon container, as I couldn't find this anywhere in the Palm Springs/Palm Desert area. Stuck it in the front, facing the East and it seems to be doing well. It gets water every other day in the summer, then every three days the rest of the year. It took a while to get settled, but it appears to be slowly growing. Just happy to have it, although I know it will take years to reach a height that will be noticeable.


On Sep 13, 2016, coriaceous from ROSLINDALE, MA wrote:

This beautiful fine-textured tree/shrub is rare in cultivation because it is slow growing. It can eventually reach 25' tall. The branches eventually tend to develop a weeping/cascading habit unless pruned and trained.The bottom of the crown is often flat because it is often browsed by livestock and other herbivores.

This tree's natural range extends through areas with very dry winters and wet summers. It grows much faster with plentiful water in summer. It is also highly drought tolerant and suitable for xeriscaping.

It can begin flowering on bare branches as the leaves begin to come in when summer rainfall begins. Flowering ranges from sparse to profuse, apparently most floriferous when bloom is preceded by drought.

Guaiacum coulteri has been ... read more


On Sep 6, 2013, AridTropics from Chandler, AZ wrote:

Ever since seeing pictures of this Guaiacum species in flower, It has been on my to acquire/ trial list. I was lucky enough to pick up a nice 1gal specimen while attending Desert Botanical's spring sale back in March.

I also made a special trip to Glendale while in town to examine a couple specimens planted in the Demo gardens to get an idea of how much this species is/was effected by freezing temperatures since documented cold hardiness seems to vary depending on information provided over the internet. Thus far, my own specimen has done well here in San Jose, CA. steadily pushing bursts of growth during warm spells through the summer in full hot sun most of the day. Regardless, it isn't a fast grower.

Because it is such a rarity, I soak it only once a week... read more


On Aug 11, 2012, PlantNutPeg from Casas Adobes, AZ wrote:

I planted a Guayacan in Tempe, Arizona. I lived there 10 years and if flourished the entire time. No, they are not easy to find. However, Shady Way Nursery in Apache Junction is a treasure trove for unusual desert plants. If you live in or near Maricopa County, youneed to know about this nursery. The Guayacan is also available at Tohono Chul Gardens in Tucson.


On Jan 9, 2011, conrehabit from Mazatlan,
Mexico wrote:

We planted 5 Guayacan trees in our property 4 years ago. They were only 20-30 cms. long at the time. They are doing very well, with watering twice a week. The picture I uploaded is from an existing tree in our 2 acre site. People tell me that it is 20 years old and it is barely 5' tall but very vigorous. I collected only 7 seeds from it last winter. Most neighbours "harvest" my tree before I know it. The 7 seeds germinated in 15-20 days in small pots in my back patio and they are doing very well. I also got 2 cuttings 2 weeks ago and Isurprinsingly, one is growing small leaves!!
I have used cow manure as fertilizer and the most commercial brand as well. The cow manure gave me good results.
I have seen at least 1 large (18 feet or taller) tree along the Free Highway 15 r... read more


On Aug 13, 2004, sonotaps from Phoenix, AZ wrote:

The Guayacan is native to Mexico and is found as far north as Sonora near Hermosillo (relatively frost free). I have one growing in my yard in Phoenix. They are drought/cold deciduous, and require a little more water here than in their native habitat, where the monsoon is more pronounced. That is not to say that they aren't suitable for xeriscape in the least. A tough plant. I've had no problem with cold in Phoenix at all with this one. The plant blooms profusely with purple flowers during the hottest part of summer in Phoenix, defying Mother Nature's fury. Have to admire that about the Guayacan. The little leaves come directly off the small branches and even the trunk with the most brilliant bright green coloring.

A beautiful shrub to small tree, but relatively hard... read more