“Creepy.”
That’s a word that could have been coined to describe Dodder, the yellow-orange, leafless, creeping vine that winds up and over other plants — and sucks out their life juices.
Many common names for this uncommon type of plant give you an idea of just how creepy folks think it is: Strangleweed, Fireweed, Devil’s Ringlet, Scald Weed, Pull-Down, Beggerweed, Witches Hair, Devil’s Gut, Hellbine and Wizard’s Net. None of those names sound like something you’d like to have in your garden.
And that is certainly the case when it comes to Dodder.
It’s easy to identify Dodder since it’s basically just a thin yellow vine – and there’s nothing else that looks like it.
Depending on the species, Dodder has either no or very low amounts of chlorophyll, the chemical that allows plants to convert the sun’s energy to food and gives most plants a green color. So instead of using photosynthesis to turn carbon dioxide, water and sunlight into food, Dodder relies on other plants to do that.
This plant sends thin yellowish tendrils up out of the soil that “sniff” out chemical markers given off by green plants. When Dodder locates a good target, its tendrils lean into the smell and when the vine reaches the green plant, it literally wraps itself around it and sinks tooth-like probes called haustoria into the plant tissue; and then, it leeches the host of life-giving water, carbohydrates and nutrients.
Dodders are some of the few true parasitic plants native to Alabama – its hosts receive no benefit from Dodder; and yet, Dodder must have a host to stay alive. Another famous parasite found in our forests is Mistletoe.
Because Dodder does not have the ability to synthesize its own food, once the plant germinates, it must find a host plant within about a week or the seedling will die after it uses up the food supply in its seed.
When Dodder has connected with one host, it reaches out for another and then another, creating a disorganized yellow net on the forest floor, or up and over shrubs or even into trees. Once Dodder matures and is attached to hosts, the original root in the soil dies and the Dodder vines are completely reliant on other plants.
As the parasite shares a host plant’s food, it weakens the plant, which can cause a number of problems, including making the host plant more susceptible to diseases, insect pests, drought and any other challenge. Dodder can also spread diseases among the many hosts that the vines connect. Most Dodder species are best suited to specific hosts. As an example, Clover Dodder will mostly parasitize clovers.
Dodder moves fast. One day, you might see a strand or two of yellow vine, and a few days later, it looks like somebody emptied a can of yellow Silly String on the ground. If you’re not afraid of having nightmares, Google time-lapse videos of Dodder tendrils emerging from the ground and waving their thin, yellow worm-like arms in search of green victims.
Technically, Dodder vines are stems with leaves that have evolved into something that looks like a tiny scale on the stem. But to the naked eye, it’s just a vine. Dodder vines do produce tiny light-colored blossoms that produce tiny pea-size fruits from mid-summer to fall. The fruits contain numerous hard-shelled seeds that can survive for years – up to 20 years, according to some biologists – in the soil before germinating. Dodder seeds collected and held in a herbarium germinated after 60 years, but it is unlikely that the same thing could occur in a wild environment.
Found worldwide in temperate and tropical areas, there are between 100 and 200 different Dodder species. All Dodders are members of the Cuscuta genus. These plants are all very similar and are hard to identify when the plant is not in bloom.
There are roughly 50 species of Dodder in North America; nine are native to Alabama, and six more are found in surrounding Southeastern states. One species, Cuscuta harperi, is only found in 12 counties — 10 in northern Alabama and two in Georgia.
Here in the Lake Martin area, species of Dodder can be found in the water, along the shoreline and in moist forest soils.
Dodder has long been used in Chinese folk medicine, and modern research has shown the plant may offer some benefit in treating human illnesses.
According to research published in 2017 in the Proceedings of the National Academy of Sciences, biologists have discovered that by penetrating multiple plants at once, Dodder vines provide a chemical highway that gives individual plants the opportunity to communicate with each other. In the study, a plant on one end of a Dodder vine network was attacked by caterpillars. It sent out a chemical “distress signal” through the Dodder vines, which gave other plants time to raise their chemical defenses and suffer less damage by the caterpillars heading their way.
Nonetheless, Dodder is considered a pest around the world, as it can do tremendous damage to crops like beans, hops, alfalfa, clover and flax. It is largely controlled by hand removing the plant, though when infestations occur outside of agricultural fields, mowing is very effective. Since Dodders only reproduce via seeds, if you do pull up Dodder vines, don’t put them in your compost, as you could spread seeds that could germinate years after the compost is spread in your garden.
Some information for this article came from the U.S. Forest Service, Britannica.com, Michigan State University, Ohio State University and the Ecological Landscape Alliance.