Soaptree yucca is a stunning tree-like succulent that makes a bold accent plant in any garden. It looks desert-tough — and it is. Here’s everything you need to know about planting and caring for this southwest desert native.
Soaptree yucca (Yucca elata) is a tree-like succulent that makes a statement. And that statement is, “You’re definitely in the desert”. Can you imagine this quintessential desert plant anywhere else?
It has slender but fibrous gray-green leaves with white margins and sharp pointed tips. As it grows, older leaves create a skirt, much like palm trees.
Plants start out looking like an ornamental grass. As they mature, they develop a trunk and then usually multiple trunks.
This plant doesn’t flower every year, but when it does, it’s spectacular. Clusters of large, bell-shaped, creamy white flowers appear on top of impressive flower stalks that grow up to 10 feet tall!
Soaptree yucca is an extremely low-maintenance plant. All it requires from you is that you plant it in full sun and occasionally give it water while it’s getting established.
There are 53 yucca species and each one is pollinated by a single species of moth. Soaptree yucca is pollinated by the yucca moth (Tegeticula yuccsella). The female moths pollinate the flowers and moth larvae feed on the developing fruit, forming a symbiotic relationship. Pretty amazing!
Why I Like This Plant
- Dramatic specimen plant
- Stunning flower stalks
- Looks good all year long
- Takes extreme heat and cold
- Virtually maintenance-free
Things to Watch Out For
All yuccas contain saponins that are toxic to dogs, cats, and horses. (While some parts are edible, don’t consume any part of a yucca unless you know what you’re doing.)
Soaptree yucca leaf tips have sharp, pointed ends that can jab you, so handle with care.
Before you get your heart set on one, be aware that these plants are an investment in the future. They are expensive and very slow growing. A decent-sized one can set you back hundreds of dollars.
Optimal Growing Conditions
If you’re thinking of adding a soaptree yucca to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Soaptree yucca should be grown in USDA Hardiness Zones 6 – 10. It tolerates intense desert heat and is cold-hardy down to -10℉.
Sun Exposure
Soaptree yucca is a tough desert native that needs full sun and tolerates the reflected heat off a hot wall or building. Don’t plant this where it gets partial shade.
Size and Growth Rate
Soaptree yucca is an extremely slow-growing plant, growing about an inch per year (!) when not irrigated. A typical mature specimen will reach a size of 6 to 15 feet tall by 6 to10 feet wide.
Plants start as a single trunk, but most add branches over time, typically fewer than seven.
Plants bloom most (but not every) spring, sending up flower stalks that usually reach a height of 4 to 6 feet, but can be as tall as 10 feet.
Soil
Soaptree yucca prefers dry, alkaline, sandy or rocky soil that is well-draining.
Other Location Considerations
Soaptree yucca grows to be quite large and has sharp points. So plant in an appropriate place, keeping the future in mind. You don’t want to ruin this plant’s shape with pruning as it matures and outgrows its space.
It is an excellent plant for night lighting. One simple spotlight will cast shadows that change the look of your yard at night from boring to sensational.
Soaptree Yucca:
The Essentials
| Common Name | Soaptree yucca |
| Scientific Name | Yucca elata |
| Origin | Chihuahuan, Sonoran Deserts |
| Plant Type | Tree-like succulent |
| USDA Zones | Zones 6 – 10 |
| Cold Hardiness | To -10℉ |
| Flower Color | Creamy white |
| Flower Season | Late spring |
| Mature Size | 6-15′ high x 6-10’ wide |
| Growth Rate | Very slow |
| Sun Tolerance | Full, reflected sun |
| Water Needs | Low |
| Pests & Diseases | None |
| Garden Friendly | Toxic to pets |
| Wildlife | Larval moth host |
How to Plant
Dig a hole as deep as and three times as wide as the nursery container. It’s generally recommended that you not add any soft fill, gravel, or fertilizer, just native soil.
However, good drainage is critical. If you know your soil is slow draining, amend with coarse sand or small gravel until you have a loose, well-drained mix.
Carefully remove the plant from the container, put it in the hole, and press the soil to remove any air pockets.
When to Plant
The best time to plant soaptree yucca is April or May. Warm soil temperatures encourage root development.
How to Care for Soaptree Yucca
Whether you’ve recently planted a soaptree yucca or have an existing plant in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water
You’re probably used to giving a plant a good soaking immediately after transplanting, but that isn’t the best practice with desert succulents like soaptree yucca.
Counterintuitively, it’s best to not water succulents for one to two weeks after planting. Then water once per month spring through fall. No supplemental water is necessary during the winter.
Once soaptree yucca is established, it can survive on rain water alone. But these slow growing plants grow faster when they’re watered occasionally.
Should You Fertilize?
There is no need to fertilize soaptree yucca, it will get all the nutrients it needs from desert soil.
How to Prune
Soaptree yucca should not be pruned, but you may want to remove lower leaves as they die. You can do this any time of year. But you can choose not to trim them and let them form an interesting-looking “grass skirt”. The choice is yours.
The only other pruning task you’ll need to do is to remove spent flower stalks. If not removed, they eventually fall over.
Don’t Confuse Soaptree Yucca With…
Soaptree yucca can be confused with many other plants.
When young, soaptree yucca could pass for an ornamental grass, a grass-like succulent such as desert spoon, or a thin-leaved agave.
You can see in the picture below how nondescript a young soaptree yucca is.
(The only reason I know for sure that this is a soaptree yucca, is because of the label.)
Yuccas are often confused with agaves. But unlike agaves, yuccas don’t die after blooming.
With its rough trunk and skirt of dried fronds, it looks somewhat like a palm. In fact, one of its common names, palmilla, is Spanish for “small palm”.
And of course, it can also be confused with other yuccas.
Plant Lover Facts
Soaptree yucca (Yucca elata) goes by a few other common names soaptree, soapweed, and palmilla. It’s native to parts of the Sonoran and Chihuahuan Deserts — Arizona, New Mexico, Nevada, Texas, and northern Mexico.
Native Americans found many uses for this plant. They made soap or shampoo from its roots and trunk (hence the name soaptree). While the saponins in the soap are toxic, they consumed the non-toxic parts of the plant — flowers, buds, and stalks. They used the fibers from the leaves to make rope, baskets, sandals, and clothing.
Soaptree yucca is a protected Arizona native plant.
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for 15 years.
Photo Credits
Arizona State University’s Virtual Library of Phoenix Landscape Plants
SWBiodiversity.org, CC BY-SA