Last updated on August 25th, 2023 at 12:32 pm
Yucca thompsoniana, also known as the Thompson yucca plant, is a species of flowering plant in the Asparagaceae family, native to the Great Plains and Colorado Plateau.
Like most yuccas, it blooms with tall flower stalks in mid-summer that are covered in powdery white flowers; these stalks can grow up to 2 feet tall. Its other common names include Santa Fe yucca and gray yucca, though this last name can also refer to other species of yucca with gray-green leaves.
Thompson Yucca Plant can grow up to 30 feet tall in the wild, but usually only reaches about six to twelve feet when it is cultivated in landscaping and gardens.
The Thompson Yucca Plant, which originates from Nevada and California, thrives in hot, dry environments and requires little water to grow. It has long, narrow leaves that are dark green on top and light green on the bottom with a white line running down the middle of each leaf.
Yucca thompsoniana has long been prized as an ornamental garden plant with dramatic and colorful plumes in the springtime. In fact, it’s one of the most popular and sought-after species of yucca in the United States and Canada, making it easy to find in nurseries or garden centers throughout these regions.
Origin and distribution
Native to Arizona, Nevada, California, and Utah. It grows at moderate altitudes in dry, desert-like conditions. Thompson yucca can also be found in parts of Mexico and some areas of Hawaii. The plant is named after Dr. Edward Palmer Thompson (1824–1911), a physician and army surgeon who was one of its first cultivators.
He discovered it growing on a hillside near Santa Fe, New Mexico, in 1853. He sent specimens to George Engelmann for description and classification.
Engelmann described it as Yucca aloifolia var. thompsoniana in 1856, but changed his mind when he saw more specimens collected by Charles Wright in 1859; he decided that they were sufficiently different from Yucca aloifolia and gave them their own species name: Yucca thompsoniana.
In 1941, botanist John Thomas Howell suggested that there might be two subspecies of Thompson yucca, subsp. thompsoniana with large green leaves and subsp. wrightii with smaller blue-green leaves, although others have disagreed with him about whether or not these are distinct enough to warrant separate taxonomic status.
Yucca thompsoniana propagation
Easily propagated by seed, which can be collected in winter and sown indoors in late winter or early spring. The division is also possible; however, due to its size, care must be taken to ensure each section has at least one growing point.
The root system is not aggressive and therefore can be easily separated from other plants without injury. Once established it is very drought tolerant and only moderately susceptible to frost damage. It prefers full sun but will tolerate partial shade.
It requires little maintenance once established and is a good choice for desert landscaping as well as xeriscaping. With such ease of propagation, the availability of seeds and bulbs throughout most of North America makes Yucca thompsoniana an excellent choice for many areas where similar-looking species are unavailable.
While many think that all yuccas are spiny, many are spineless with soft leaves like those of a lily. However, Thompson yucca does have sharp spines along the edges of its leaf margins that could cause discomfort if handled improperly.
This plant is considered poisonous and should be kept away from pets and children.
Yucca thompsoniana care information
Yucca thompsoniana is a tough plant that requires little attention once established. Hardy to hardiness zone 7, it can withstand full sun to part shade and poor soil conditions. Although drought-tolerant, regular watering will encourage vigorous growth and prevent brown leaves.
The flowers appear in summer, growing up to 3 feet tall atop strong stalks. They are prized by pollinators as well as people with allergies due to their lack of fragrance; they’re often dried for floral arrangements or given as gifts.
Light requirement
The Thompson yucca plant prefers full sunlight, with at least six hours of direct sunlight each day. The yucca thrives in zones 4 to 9. A yucca should never be planted in a shaded area, as it requires sun for proper growth and survival.
In fact, a lack of light can cause a yucca to slowly die off. Choose a location that receives plenty of sun exposure but isn’t exposed to harsh winds or scorching heat.
Soil/potting mix
To ensure Yucca thompsoniana plant’s best health, repotting needs to occur every 2–3 years. The best soil for its cultivation is one that consists of a mixture of sand and peat with a neutral pH value between 5.8 and 6.5.
Because it requires very little maintenance, Thompson yucca plant can be placed in any potting medium. However, optimal growth rates are achieved when treated with composted manure or composted pine bark mulch.
Watering
Yucca thompsoniana thrives in hot and dry regions, so water it sparingly, especially during winter. It may not need to be watered at all! If you do decide to water your plant, allow it to drain thoroughly after watering it.
Overwatering Thompson yucca plants can cause brown leaves and root rot. The soil should be kept moist, but not soggy. During hot weather, water frequently enough to keep it from drying out completely, but don’t soak it either.
If using a soaker hose to water your plant, make sure you place it on a timer and that you choose one with small holes, otherwise too much water will run off rather than getting absorbed by your plant’s roots.
Fertilizer
If your yucca thompsoniana (thompson yucca plant) is growing in a container, feed it once every three months from April to October with a balanced 20-20-20 fertilizer diluted by half. Feed it once a month during its dormant period from November to March with water.
You can also use an indoor plant food formulated for foliage plants every time you water.
For outdoor yucca thompsoniana, fertilize them twice a year in early spring and late summer using a general-purpose fertilizer such as 10-10-10 or 12-12-12 at one-quarter of the recommended strength. Apply no more than 1 pound of nitrogen per 100 square feet of soil surface area. Avoid fertilizing them too much, as they are susceptible to root rot when overfed.
Thompson yucca plant temperature
Yucca thompsoniana plant will thrive in a wide range of temperatures but does best in cooler conditions between 45 and 70 degrees Fahrenheit. The temperature in your home should be fine for it.
However, if you live in an area that regularly experiences freezing temperatures during the winter months, you’ll want to bring your plant indoors or move it to a sheltered location before cold weather hits. If you keep it outdoors during the winter months, cover its roots with mulch to protect them from frost damage.
Humidity
While Yucca Thompsoniana is native to a dry, rocky habitat, it can survive in almost any environment. However, if you are growing your plant indoors or in an area with low humidity, misting and propagating from cuttings will be your best bet for a lush green lawn of foliage. Be sure to water occasionally, only when soil becomes dry about 1 inch down to prevent rot and mold growth on leaves. Mist every other day for healthy foliage development.
The ideal humidity range is 40-60% for optimal growth. If you are growing your plant indoors, try using a humidifier to help keep humidity levels high. You can also place your plant in a room with higher humidity, such as a bathroom or kitchen.
Just be sure to avoid drafts from windows and doors that could dry out leaves. Also remember that Yucca Thompsoniana is an evergreen, so it will still look great year-round even if you are unable to provide optimal conditions for its growth during certain seasons of the year.
Pruning
For pruning, you can do as much or as little as you like. If you only have a few of these plants and want to increase their height and width, I would definitely prune. Some gardeners also choose to trim their yucca to give it a more natural shape.
To trim your yucca, grab some sturdy gardening shears and find an angle that is pleasing to your eye. Cut off bottom foliage until you’re satisfied with how they look. When trimming, be sure not to cut into any of the branches above. Once trimmed, let them rest for about two weeks before watering them again.
When to repot
Thompson yucca plants need to be repotted regularly because they have a high rate of growth. You should repot your plant every 1-2 years. To do so, you’ll need to cut away some of the root balls and loosen up any roots that have become densely packed together.
After doing so, it’s a good idea to reposition your plant and then give it a fresh dose of fertilizer before watering thoroughly.
Dormancy/Winter rest
Thompson yucca plants are deciduous. After flowering in late spring, most of them die back to a basal rosette. During fall and winter, they go dormant, turning brown and losing their leaves but staying alive beneath the ground.
When new growth begins in spring, it may be some color other than green, it could be red or maroon or chartreuse, and occasionally makes a stunning show on these evergreen-like plants before they return to their normal green coloration.
For gardeners in cold climates, it’s important to remember that Yucca thompsoniana needs at least one month of dormancy; if your climate doesn’t offer that much time below 45 degrees Fahrenheit (7 degrees Celsius), consider moving your plant indoors for its winter rest.
This is also true if you live in an area with mild winters and want to enjoy your yucca throughout all seasons. In areas with warm winters, however, there is no need for a dormant period.
Yucca thompsoniana flower & fragrance
The Thompson yucca is named for its botanist, William Thompson. With striking foliage and long, sword-like leaves with prominent parallel veins, plus pretty bell-shaped yellow flowers and a pleasant fragrance that attracts pollinators like bees and butterflies, it makes an attractive addition to any garden or landscape.
Beaked yucca growth rate
Yucca thompsoniana has a slow to average growth rate. The yucca will grow one foot every three to five years in most areas. Leaves emerge from the ground in Spring or Fall, grow quickly, and can reach five feet tall by late summer. Most varieties of yucca are deciduous, but there are some evergreen varieties as well.
Thompson’s leaves can be up to two feet long with sharp spines along their edges. Both male and female flowers appear in clusters on top of a stalk usually appearing from June through August.
Toxicity
Although Yucca thompsoniana is not toxic, it does contain saponins that can irritate skin and eyes. If you have allergies to other members of its botanical family, then you may be allergic to yucca as well. Keep your dog away from leaves and flowers, which are poisonous to animals.
Yucca thompsoniana hardiness zones
Yucca thompsoniana thrives best in USDA hardiness zones 4 through 9. However, it can be grown as an annual outside of these zones. If you are growing yucca thompsoniana as a perennial, you should take extra care to ensure that it is not exposed to freezing temperatures.
Pests and diseases
Yucca thompsoniana is very susceptible to overwatering and root rot, so it’s important to avoid over-watering. These plants can also become infected with disease if exposed to poor air circulation. It is recommended that you either position your plant outside in order to keep it well ventilated or place it near a window where fresh air can reach its leaves.
Finally, check your plant regularly for signs of pests such as aphids, mealybugs, and spider mites.
Conclusion
Yucca thompsoniana is a stunningly beautiful ornamental plant that thrives in any well-drained, sunny spot in your garden. They’re easy to maintain and have minimal needs, making them perfect for just about anyone.
If you’re looking for something new to brighten up your yard or patio but need something tough and durable, look no further than Thompson yucca.
