LONGMONT – Hellweed. Devil’s gut. Strangle tare. Devil’s fuge. If you think the garden is a tranquil place, take another look. Just outside your door, vampires might be lurking, only you needn’t worry – they like their prey soundless and unable to run away.
The plant kingdom has its share of monsters and ghouls that find easy pickings on leaf or stem. And some of the more interesting fiends are those within their own clan: parasitic plants that feed on the labors of others. Take a look at three common parasites we have right here in Colorado.
Cuscuta, also known as Dodder, is a string-like, parasitic plant that only produces a limited amount of chlorophyll, so cannot make its own food via photosynthesis. To feed itself, it attaches to other plants, sucking the nutrients out for its growth.
This vampire weakens the host, and since plants have no voice, the quiet struggles often go unnoticed by us humans. Dodder is commonly found in farm fields and especially destructive to crops such as asparagus, alfalfa, beans, and tomatoes but it also grows in our landscapes on English ivy, petunias, dahlias and chrysanthemums.
Dodder is a bright yellow, leafless plant with branching stems that resemble string. Its seeds germinate like other seeds, but once growing, the stems begin to grow in a questing fashion until they encounter a nearby plant to parasitize (check out how in this video https://youtu.be/5gPuXtmrP0E). Once they’re firmly attached, the dodder root withers away. The mature plant lives its entire life feasting upon its host, never again rooting to the ground. Pull and destroy any plants that become infested.
Our native forests are rife with their own monsters, especially dwarf mistletoe. Of the 42 species of known worldwide; five lurk in Colorado’s forests. A common problem in Colorado forests, Dwarf Mistletoe prefers ponderosa and lodgepole pines, although they find Douglas-fir, piñon, limber and bristlecone pines to be tasty hosts as well.
Dwarf mistletoes are small, yellow-green, leafless parasitic plants that kill by inserting root-like “sinkers” into the bark and wood of the tree. Once attached, they slowly feed on the tree’s food and water. Parts of the tree above the dwarf mistletoe die from the lack of food, while at the feeding site distorted growth, called witches broom, can occur. Over time, the tree succumbs and dies.
Supersizing the fun is dwarf mistletoe’s method of seed dispersal: it expectorates its sticky seed at about 60 mph, letting fly it’s spawn to take hold of other trees in the forest. Like dodder, it can be exorcised through pruning.
The clown in the movie It isn’t the only ghoul hiding behind a cheerful mask: Indian Paintbrush (Castilleja) is a brightly colored flower that has a killer streak. Found in meadows and open clearings it is easily recognized by its orange-red, spike-like flower.
A perennial, its seeds are fussy and hard to germinate, requiring sacrificial seeds of other plants to be sown with it. It uses these other plants as a backup plan for when things get tough in the meadow: if malnourished it will parasitize the roots of its neighbors.
Fortunately these plant vampires aren’t running rampant, but it’s worth a gardener’s time to be on the lookout for them. You won’t need garlic or a crucifix to eliminate dodder or mistletoe, just some pruners, and Indian Paintbrush is very pretty.
By Carol O’Meara, Colorado State University Extension. Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Colorado State University Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, e-mail firstname.lastname@example.org or visit ext.colostate.edu/boulder.