TA Tidbits # 69 Dodder: The Golden Parasite of the Tortolita Trails
- Joseph C Thomas
- Jan 19
- 3 min read
As an avid hiker exploring the trails of the Tortolita Mountains and the surrounding Sonoran Desert near Tucson, I've encountered many fascinating plants and wildlife.
One plant that always catches my eye is dodder, a unique parasitic vine that thrives in the Tortolita Mountains area. In December 2025, I spotted it while hiking the Wild Mustang Trail in the Tortolita Mountains. It was draped over shrubs, looking as vibrant as ever in the winter light and in bloom. I snapped a couple of photos to capture its tangled beauty, its gold strands weaving through the host plant.
I've observed dodder many times in recent years while hiking along the Wild Burro Wash and the Alamo Springs Trail. It seems to appear in moist microsites, especially after monsoon or winter rains, adding a splash of color to the arid landscape. To me, it looks just like golden Silly String — those bright, tangled strands flung across bushes and herbs, as if nature were playing a prank!
Dodder, scientifically known as Cuscuta indecora (commonly called bigseed alfalfa dodder or pretty dodder), is a native perennial herb in the morning-glory family. It's a vine-like plant with slender, thread-like stems that are typically yellow-orange, though sometimes transparent or slightly greenish. Lacking true roots or functional leaves, it doesn't photosynthesize on its own. Instead, it relies entirely on host plants for survival. In our area, it parasitizes a variety of herbaceous and woody species across desert, upland, and riparian habitats. (Southwest Desert Flora, Arizona Cooperative Extension)
The plant's small, showy white flowers appear in clusters, each with five petals and five sepals, blooming from spring through fall depending on moisture. These give way to round capsules filled with numerous seeds that can remain viable in the soil for 5 to 10 years, waiting for the right conditions to germinate. In the Tortolita region, dodder is most visible during the growing season after rains, from late spring to early winter, though I've seen it thriving in cooler months like December.
Its survival strategy is pure parasitism: dodder attaches to hosts via specialized structures called haustoria, which penetrate host tissues and siphon water, nutrients, and sugars. This can weaken or even kill the host over time, making dodder a bit of a plant villain. But it's a natural part of the wild Tortolita ecosystem, reminding us of the intricate dependencies in the Sonoran Desert. In the Tortolita area and the surrounding Sonoran Desert, it commonly parasitizes herbaceous and woody plants. (Convolvulaceae of Sonora, Mexico. Cuscuta, Arizona Cooperative Extension)
Dodder is one of several parasitic plants in the Tortolita Mountains. One common parasitic plant in the Sonoran Desert is desert mistletoe (Phoradendron californicum), which parasitizes mesquite and other leguminous trees. There are also other types of mistletoe in Arizona. These mistletoes are hemiparasites, meaning they can photosynthesize but still draw water and nutrients from their hosts. Here's an example of desert mistletoe on a mesquite tree in the Sonoran Desert. (A Flora of the Tortolita Mountains, Pima and Pinal Counties, Arizona)
One of the most intriguing aspects is how a germinated dodder seed locates a host. With only 5–10 days of stored energy, the pale shoot emerges from the soil and begins a desperate search. It detects chemical cues, volatile compounds released by nearby plants, and grows toward preferred hosts. It also senses light quality, moving toward shaded areas that indicate vegetation. The shoot performs a slow, circular motion called circumnutation to "forage" until it touches a stem, then coils around it and forms haustoria to connect. If it misses, the seedling dies — high stakes in the plant world! (Arizona Cooperative Extension)
Next time you're hiking in the Tortolita Mountains, keep an eye out for this golden freeloader. It's a great example of the Sonoran Desert's resilient flora.
I’ve yet to spot any dodder in the Tortolita Preserve, so if you do, share your sightings with the Tortolita Alliance — we're building a community knowledge base of our local plants and animals!
— Joseph, Tortolita hiker chasing Sonoran Desert wonders
This article was generated with the assistance of AI. While the content aims to be accurate and informative for our community, AI outputs may contain errors or omissions. Always cross-verify details with field guides, expert consultations, or personal observations during your own hikes in the area. The Tortolita Alliance encourages community contributions to refine and expand our shared insights on the unique ecosystems of the Tortolita Mountains, the Tortolita Preserve, and surrounding lands.