Welcome to the wonderful world of weedy plants!
Weeds are superevolutionary products of human civilizations and activities - without humans there would be no weeds, just wild plants.

Thursday, November 7, 2013

Who stole my weeds?

A hilarious news story has been making the rounds recently, about a property owner in Portland, Oregon, who is upset that someone is trespassing and picking the weeds on this property. The story broke on  KATU, a local news station and there are some hilarious comments below it, and then was picked up by Fox News).  The owner is blaming the chefs of neighboring restaurants, and say that not only do they pick the weeds, they leave recipes after them.

To me, this sounds like a April 1 joke (except it wasn't published on the first of April).  First, if you have weeds, wouldn't you be happy to get rid of them?  Second, I doubt chefs would pick weeds in urban lawns that most likely have been sprinkled with pesticides, cat urine, and exhaust fumes plus other unmentionable things.  Third, chefs leaving recipes? This story smells funny all the way from Oregon.  It is possible it is true of course, but that remains to be seen.

search for Urban Edibles in Molenbeek
Urban foraging for edible plants in Belgium. Would you eat the plants from this spot?
Creative Commons photo by foam on Flickr.
However, the idea that chefs would harvest weeds for serving at upscale restaurants are likely and part of a new trend of eating a larger variety of greens, being 'on the edge' of novelty, and of course, being extremely locavorish.  This was already described in the great book Foraged Flavor by Wong and Leroux, and has its roots not only in traditional Italian cuisine with its wild spring greens but also in many other ethnic cuisines.

I grew up picking wild stinging nettles in early spring, when the shoots were small (but still stung).  You had to were gloves, and our patch was so small that only only got enough for one meal per year (or rather, I think we gave up after that).  You cooked the soup down like spinach soup and all the stinginess was gone after boiling, add some cream or milk, and then served with a hard-boiled egg cut in half that floats like two boats in the green sea.  Yummy, and here is a recipe.  The stinging nettles are certainly weeds. 

Monday, October 21, 2013

The good side of an invasive

クズ (Kudzu) 

The non-native species Pueraria lobata, commonly known as kudzu (or sometimes mile-a-minute weed, but it is not the same plant as in this blogpost), is a creeping, climbing legume vine from japan and china. “Kudzu” literally means ‘plant’ in Japanese. Like most invasive species, kudzu is considered a noxious weed in our part of the world. The ecological damage caused by this plant is solely due to its ability to out-compete neighboring species for resources such as light. As it grows over other plants, its large leaves blocks sunlight and often plants beneath the kudzu are suffocated. 
Kudzu, The Vine That Ate the South
"The Vine that ate the south." Kudzu invasion in forest.
Creative Commons image by
Frank DiBona on Flickr.

In its home countries, however, it has proven to be a herbal remedy for a variety of troubles such as hair loss and alcoholism. Such two-sided traits beautifully sum up the contradiction of invasive species. Though malicious in some environments, invasive species can be used to our benefit in other area. As seen in our last post about invasives, significant efforts have been put in to mitigate these weeds. However, recent research has shown that some of their characteristics could be beneficial to society.

How did kudzu get here? In 1876, during the US’ 100th birthday exposition in Philadelphia, the Japanese government constructed a native Japanese garden for the exhibit. The imagery of the leaves appealed to many American gardeners leading to the vast spread of kudzu in local gardens as ornamental plants from a Florida nursery that propagated and sold the plant. Kudzu was also actively promoted as a forage plant and soil conservation plant in the US during 1930s and 1940s. But it didn’t stay in gardens and on roadsides, it quickly escaped and took over the native forest. 

In addition to this, the US Armed Forces used kudzu as camouflage for equipment in Vanuatu and Fiji in the Pacific. Needless to say, the plant has become classified as an “unwanted organism” in these countries too.
The root, flower and leaf from kudzu are used to make herbal medicines. In Traditional Chinese medicine, the use of natural resources is the norm. In fact, the use of herbal-based medication is still a leading treatment for disease in many areas of the world. Kudzu is noted to have been used in Chinese medicine before 600 AD. Its uses range from treatments of menopause symptoms, muscle pain, stomach pain, fever, diarrhea, sinus infections, high blood pressure, to irregular heartbeat, chest pain and various other illnesses.
This medicine features the roots and flowers of the Kudzu plant,
which aims to lessen the desire and craving for alcohol. In addition
it aids the body's natural detoxification processes.
Source: vitaminshoppe.com

Despite its popularity on the Asian continent, the herbal remedy from kudzu has so far lacked sufficient scientific evidence to prove any effects. So can this weed actually help the medical world?

Kudzu promises a remedy for an illness of much importance to society. It has been used to “cure” alcoholism, or more accurately, decrease the symptoms of drinking and the urge to do so. In 2012 Penetar et al published a study conducted at McLean (a hospital affiliated with Harvard University) on kudzu’s effects on alcohol consumption. It was found that physiologically, kudzu can increase the blood flow to the brain and heart. “Wherever blood goes, alcohol goes”, states professor Scott Lukas on the research team. The theory is that this allows for a quicker response time, and the ability for the body to have enough alcohol in less time. Simply put, you get drunk faster on less alcohol. 

First tested on rodents, the intake of alcohol decreased significantly in the lab results when they were given kudzu. When tested on humans, the group treated with kudzu drank significantly less than the placebo group. The research states that alcohol consumption was almost cut in half!  

More research into the how’s and why’s of such effects could lead to very improtant discoveries regarding potential contributions of this invasive species to medicine. 

Check out an old poem written on this historic weed!

Wednesday, October 2, 2013

The minute mile-a-minute mitigator

A minute of natural history

Mile-a-minute overtaking trees.
by Furryscaly via Flickr CC
Mile-a-minute (Persicaria perfoliata) is one of the most pervasive and damaging nonnative invasive plant species in the United States.  Mile-a-minute, a member of the Buckwheat family (Polygonaceae), was first introduced to the U.S. in 1890 from its indigenous range of Asian and Southeast Asia.  The plant did not successfully establish a permanent population in the U.S. until a reintroduction in the late 1930s when a Pennsylvanian nursery germinated Holly seeds from Japan and in doing so, the stowaway mile-a-minute seeds.
Approximate U.S. distribution as of July 2013. Source: Eddmaps.








Mile-a-minute earned its name

Mile-a-minute leaves and ocreae. 
by Leslie J. Mehrhoff
Mile-a-minute is an annual trailing vine with distinctive alternate triangular leaves.  Another identifying trait is the round saucer-shaped structures, or ocreae, which occur at nodes and branching points along the stem.  Self-pollinating flowers and subsequent fruit arise from the ocreae. Recurved barbs along the stem and leaf petioles make this plant particularly unpalatable to most potential herbivores.  Low predation rates in the U.S. coupled with the species’ prolific seed production and readily available dispersal mechanisms (water and birds) are traits characteristic of an exceptionally weedy plant.

Following annual die-back mile-a-minute 
leaves and stems continueto weigh down the 
plants they have climbed & shade groundcover.
by L. J. Mehrhoff via Invasives.org
Most impressing, and most ecologically damaging, is mile-a-minute’s growth rate of up to six inches a day, or 77’ (33.8 m) in a single growing season.  For perspective, mile-a-minute could cover the Statue of Liberty from heal to torch in two growing seasons.  Methods to control this invasive plant include traditional methods of manual removal and chemical pesticide applications.  However, given the rate at which mile-a-minute spreads, traditional methods are not practical of well-established or remote populations.  In 1996, the U.S. Forest Service began researching possible biological control agents.  

Fighting nonnative with nonnative: biological control

Biological control is a way of using an invasive species natural predator or disease, most often from the species’ indigenous region, to reduce the invasives’ proliferation and dominance.  Finding a biological control agent that is truly host-specific to your target species takes a lot of research.  Inadequate research into a control agent’s life history and ecology prior to release may have dire consequences, which are worse than the original cause for their introduction.  A classic example of biological control gone awry is that of Cane Toads introduced to Australia in 1937.  Thankfully, the science of introducing biological control agents has come a long way!

Adult R. latipes are approx. 2mm long.
by Amy Diercks, via Invasives.org
Colpetzer et al. published a study in Biological Control (2004) examining potential biological control agents for use on mile-a-minute.  Results from their study supported the introduction of a small host-specific weevil from Asia, Rhinoncomimus latipes, which feeds on mile-a-minute roots as a larvae and foliage as an adult.  In 2004, the U.S. Department of Agriculture approved the use of the weevil as a biological control agent.  After several regional releases, the introduced weevils have successfully established populations throughout the Mid-Atlantic region. 

Ongoing weevil releases, such as one recently conducted in Union County, New Jersey, help sustain and expand the current weevil populations.  Led by state and county agriculture officials, the recent release of 2,000 weevils in Watchung Reservation, Union County’s largest park, is sure to reduce local mile-a-minute growth in the coming years.

Below is a video from a weevil release in New York City

Amy Diercks, Bugwood.org

Sunday, August 18, 2013

A Texan Turf War

·        Imagine Dallas for a moment. Not the largest metropolitan area with over a million people, but historic Dallas.  I know what you are thinking of  - miles and miles of… turfgrass! Am I right? No?  Well, according to the city planners in Dallas, a nice green lawn is exactly what they had in mind.  A homeowner with a slightly longer view of history has incurred the ire of the Landmark Commission of Junius Heights Historic District for his “historically inappropriate” yard of cacti, yucca, mesquite, agave, and native prairie grasses.

I realize that the city planners want things to look nice – that is, how things looked when they were growing up in the 60’s , 70’s and 80’s – but I have to question the appropriateness of sod in northern Texas.  To begin with, this area was historically covered with mixed prairie: a super diverse mix of grasses, cacti, and yucca. Even if the Landmark commission adheres to a very short view of history, the ecological appropriateness of using dwindling water supplies to support non-native invasive turfgrass seems misguided and foolish. As is the case in many cities in the Southwest, water supply is dwindling, while water demand is skyrocketing. In 2003 the average Dallas citizen used almost 240 gallons of water a day.

 Xeriscaping seems the most appropriate and responsible choice. And prairies can be beautiful! Check out these photos from the largest remnant of pristine tallgrass prairie. Waves of rolling prairie grasses would be a gorgeous addition to suburbia. 

Wednesday, April 3, 2013

Invasive Species Sushi

A Connecticut Sushi chef uses invasive species to re-imagine sushi. Although his dishes showcase invasive aquatic species, his formative experiences were harvesting burdock and lamb's quarters with his mother as a child in New Haven.

How might we re-imagine food using weedy species? Corporate monocultures are arguably as destructive to native habitats as improper fishing practices are in aquatic systems. Many of the cursed weeds of lawns and gardens were once widely considered edible and delicious.

In the comments section of the article, some readers list their own food ideas. Isabel mentions wild mustard greens, purslane, dandelion flowers, kudzu and Japanese knotweed. How do you use weedy plants? Send us your re-imagined weeds salad, tea, or stir-fry recipes!