Home / Blogs / The Wetland Vampire: Dodder
October 28, 2021
Dodder tends to form a dense web of orange tendrils that spread across and intertwine with various host plants (Photo Credit: Arthur Haines).
Wizard’s net, devil’s guts, witch’s hair: all of these names bring to mind images of fine tendrils of mysterious threads. In reality, they are all common names for some of the approximately 200 plants within the genus Cuscuta, also known as dodder. The name dodder comes from the Middle English word “daderen,” which means to quake or tremble, but it is uncertain what the actual connection is between trembling and this parasitic plant. Perhaps the host plant that it parasitizes trembles under the dodder plant’s weight? Or quakes from fear of its impending clutch?
The “fangs” of a dodder plant, or its haustoria, are the slight protrusions seen on the vine (Photo Credit: Mironmax Studios/Shutterstock).
Dodder is a peculiar specimen, with traits not commonly seen within your average mixture of wetland species. It does not contain much chlorophyll, or any chlorophyll at all in some species, and therefore has limited photosynthetic potential; rather, it parasitizes a host plant and receives its nutrients that way. Using rootlike tendrils called haustoria, dodder pulls nutrients from its host. Some, like this NPR article, have compared dodder to a vampire since it “sinks its fangs into its victim and starts drinking” once it has latched onto a host plant. It has small scales in place of the usual photosynthetic leaves and its lack of photosynthetic potential correlates with its orange color- limited chlorophyll results in an absence of green coloration.
Once the fangs of dodder sink into its host, it no longer requires roots and this vampire-plant is free to take flight, attaching itself to other neighboring plants. Since it intrudes into multiple different plants with its haustoria, dodder is often the bearer of disease, spreading viruses and bacteria between plants during its parasitization process.
While it is often regarded as a farm pest, particularly on cranberry plants, there are several native species of dodder within the Chesapeake Bay Watershed (in addition to many nonnative species that have entered the region). One prevalent species across the watershed is common dodder, Cuscuta gronovii. This species has small white flowers that are pollinated by wasps and it generally grows in wet, disturbed areas. Not many animals feed on common dodder, or dodder species in general, but it does support local pollinators.
Cuscuta gronovii develops small white blooms starting in July and persisting through October; the flowers are commonly pollinated by wasps (Photo credit: R.W. Smith, University of Michigan).
During each of the handful of times that I’ve seen dodder, its spooky orange color has stood out dramatically in contrast with the surrounding green vegetation. It certainly does look like some wizard’s net, the devil’s guts, or a witch’s hair as it sprawls across the nearby plants in an orange tangled web. While its erie presence may be of concern in certain situations, the native dodder species add an interesting diversity to survival techniques employed by plants in this region. It is always an exciting find when working in the field – just don’t let it spook you too much!
Pennsylvania Forests Projects Coordinator
Forests for the Bay