Yellow dot is an emerald green ground cover that can be grown in desert shade. When in bloom, it pops with a scattering of daisy-like flowers. Here’s everything you need to know about growing this delightful Central American native in this complete care guide.
If you miss seeing refreshing expanses of grass, yellow dot (Sphagneticola trilobata) is a lush, “grass green” ground cover to consider. It looks like it would be more at home in a woodland, but it grows surprisingly well in desert gardens.
It has slightly succulent, somewhat prickly leaves and sunny, daisy-like yellow flowers that bloom sporadically spring through fall.
While not ideal for every spot in the desert garden, it definitely has its niche. Unlike most plants that grow in the desert, yellow dot prefers some shade and a moderate amount of water, especially during summer months. This makes it an excellent ground cover to plant under trees or on the north side of a building.
Once established, it forms a dense mat that keeps weeds at bay.
Why I Like This Plant
- Emerald green foliage
- Sunny yellow flowers spring through fall
- Grows fast
- Forms a weed-smothering mat
- Thrives in desert shade
Things to Watch Out For
It’s not suitable for areas that get heavy foot traffic since these plants are easily crushed or broken. (But it’s good to know that if they do get trampled, they quickly grow back.)
The slightly prickly leaves can cause contact irritation in some people.
If you like to grow plants that support local wildlife, yellow dot does not seem to offer any particular benefits to native wildlife.
Optimal Growing Conditions
If you’re thinking of adding yellow dot 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
Yellow dot should be grown in USDA Hardiness Zones 9 – 11. It tolerates desert heat, but is sensitive to cold. Plants die back when the temperature drops below freezing, but survive temperatures down to 25℉ and bounce back in the spring.
Sun Exposure
Yellow dot is not fussy about sun exposure. It tolerates everything from full sun to deep shade but performs best in part shade where it can get some relief from the sun. The dappled shade under a tree is ideal.
Size and Growth Rate
Yellow dot is a fast-growing ground cover. It reaches 1 foot tall and can spread to 6 feet across. It easily roots when its stems come in contact with moist soil, forming large mats.
Soil
Yellow dot prefers sandy soil, but will grow well in any well-draining native soil.
Other Location Considerations
Yellow dot makes a beautiful “spiller” in large patio planters, raised beds, or hanging baskets. It can be planted on slopes for erosion control or allowed to cascade over rocks or walls.
Yellow Dot:
The Essentials
| Common Name | Yellow dot |
| Scientific Name | Sphagneticola trilobata |
| Origin | South & Central America, Mexico |
| Plant Type | Perennial ground cover |
| USDA Zones | Zones 9 – 11 |
| Cold Hardiness | To 25℉ |
| Flower Color | Yellow |
| Flower Season | Spring, summer, fall |
| Mature Size | 1′ high x 6’ wide |
| Growth Rate | Fast |
| Sun Tolerance | Full sun to full shade |
| Water Needs | Moderate |
| Pests & Diseases | None |
| Caution | Contact irritation |
| Wildlife | None |
How to Plant
The rule of thumb when planting any ground cover in the desert is to dig a hole twice as wide as the root ball but no deeper. Since yellow dot prefers sandy soil, consider amending with coarse sand, especially if your soil doesn’t have good drainage.
When to Plant
The best time to plant yellow dot is in the fall. This gives it three seasons to grow roots and get established before the following summer.
The second best time is in spring, the earlier the better. This still gives your plant time to get established before the intense heat of June arrives.
How to Care for Yellow Dot
Whether you’ve recently planted yellow dot or have existing plants in your yard, here’s how to take care of them to keep them healthy and looking their best.
How to Water
Once you’ve got your yellow dots in the ground, watering is your most immediate concern. The University of Arizona recommends watering newly planted ground covers every 2 to 3 days for the first 2 to 4 weeks.
Since it’s not truly a desert plant, it needs a moderate rather than low amount of water. Water every 10 to 14 days in the spring, fall, and winter and every 2 to 5 days in the summer. Of course, plants that grow in the shade need less water than plants that grow in the sun.
How much water you should give your plant with each watering depends on the diameter of your plant and will change as it grows. You can use this chart as a guide.
| 1 foot diameter | .5 gallons |
| 2 feet diameter | 2 gallons |
| 3 feet diameter | 3.5 gallons |
Should You Fertilize?
As a ground cover, yellow dot must often compete with other plants for nutrients. So lightly fertilize it a few times per year between spring and fall to ensure optimal growth and blooms.
Pruning & Propagation
If your yellow dot experiences cold damage, prune it in the spring after the risk of frost has passed.
Yellow dot is an easily managed ground cover that can be trimmed anytime it encroaches on sidewalks, driveways, paths, or anywhere else you don’t want it.
You can put those cuttings in potting soil to propagate new plants. You can also propagate by layering. When stems are in contact with moist soil, they’ll grow new roots. You can use these newly-rooted sections to create new plants.
Is Yellow Dot Invasive?
You may have heard that yellow dot is invasive. It is, but not here.
It has naturalized around the world and is considered invasive in Southeast Asia and parts of Australia. I was surprised to learn that it is considered one of the world’s 100 worst invasive species (!), albeit not in the desert southwest. In the US, it’s considered invasive in Florida and Hawaii.
Plant Lover Facts
Yellow dot also goes by the common names creeping-oxeye, Singapore daisy, and wedelia. Its current scientific name is Sphagneticola trilobata, but its previous name, Wedelia trilobata, is still in use.
It’s native to Central America and the northern half of South America where it grows in seasonally dry tropics. Its range also includes western Mexico, which includes areas within the boundaries of the Sonoran Desert.
Studies have found compounds in yellow dot that have anti-inflammatory, anti-microbial, and analgesic properties. It has been used traditionally used to treat cold, flu, fever, and infection.
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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 over 15 years.
Photo Credits
Ronggy, Public Domain, Wikimedia Commons
Hans Hillewaert, CC BY-SA 3.0, Wikimedia Commons