Garlic Mustard: A Destructive Yet Delectable Invasive

What is it?

Garlic mustard photo

Young garlic mustard. Photo from nps.gov.

You probably know garlic mustard even if you don’t know you know it. Odds are, it has invaded forest areas near you as it has much of the midwest. Garlic mustard, Jack-In-the-Bush, or Alliaria petiolata is a non-native understory invasive plant in North America. Garlic mustard was brought to the Americas nearly two hundred years ago from Europe as a medicinal and culinary herb. Today, it can be found in nearly every county of Ohio.

Crushed garlic mustard leaves have a distinct garlic-y smell, giving the plant one of its names. Its scent is one way to identify the plant. Otherwise, garlic mustard is a biennial (it has a two-year life cycle) and looks different based on its life stage. First-year garlic mustard grows in rosettes close to the ground. Young leaves are round or have kidney shapes and often have purple stems. In its second year, garlic mustard is easier to identify and grows up to three or four feet. It has triangular, heart-shaped leaves with toothed edges. Garlic mustard’s flower is white and four-petaled. To learn more, check out this online resource from the Ohio Invasive Plants Council.

Why is it a problem?

Non-natives follow the “Tens Rule,” meaning that one in ten non-native species will become established in their new environment, but only one in ten of those established species will become invasive. Those few invasive species pack a big punch. Like all non-native invasives, garlic mustard wreaks havoc by out-competing native plants in foreign locations with no natural controls. For instance, our growing deer population does not eat garlic mustard because deer did not evolve and adapt to eat it. This means native understory plants are eaten by deer when garlic mustard continues to spread. Native food-webs and ecosystems are thrown out of balance by invasives like garlic mustard.

Garlic mustard flower

Mature garlic mustard. Photo from nps.gov.

One garlic mustard plant can release thousands of seeds that will remain viable in the environment for up to seven years. This makes it easier for garlic mustard to spread and overwhelm an area, decreasing its biodiversity and health. Most commonly, the plant thrives in forest and edge habitats. Garlic mustard sprouts earlier in the spring than most native species. When native species eventually emerge, garlic mustard blocks sunlight making it more difficult for natives like our beautiful wildflowers to grow. Garlic mustard is particularly damaging because it secretes a compound called sinigrin into the soil that destroys fungal networks that support native species. This makes it even more difficult for resident native plants to thwart the invasive and lessens native plant’s biotic resistance.

Garlic mustard has transformed our natural ecosystems. It can out-compete tree seedlings which halts the recovery of forests. Garlic mustard alters the habitat of mollusks and salamanders, threatening their survival. The West Virginia White Butterfly is particularly endangered by garlic mustard. The butterfly lays its eggs on the plant because it secretes chemicals similar to the butterfly’s host plants. In reality, this is just a disguise as garlic mustard is toxic to the butterfly.

What to do about it?

Removing garlic mustard requires time and vigilance. Because garlic mustard seeds last in the environment, it can take nearly seven years to exhaust the seed bank. Nonetheless, we can all try to fight back against this invasive plant. Garlic mustard can be mechanically removed via pulling and cutting in your yard and local areas. Some chemical solutions exist and even biological controls are being explored. Here, we will focus on mechanical controls. To pull garlic mustard, pull from the base of the stem to remove the entire root system. Try to pull the weed before it seeds. In large infestations, it may be more manageable to cut garlic mustard close to the ground. Either way, be sure to bag and throw out your pulled or cut plants rather than composting them or leaving them at the site, as this will only continue to spread the seeds.

garlic mustard pesto

Garlic Mustard Pesto. Photo by Yossy Arefi. https://food52.com/recipes/28281-garlic-mustard-pesto

Or, rather than sending the weeds to a landfill, you can eat them as the Europeans intended! Garlic mustard is a tasty and nutritious plant that is an excellent source of vitamin C. Garlic mustard can be added to salads, made into pesto, and much more. You can find a collection of various recipes here. Garlic mustard should be harvested when young because older plants are more bitter and contain cyanide so therefore must be cooked thoroughly. Garlic mustard shoots are similar to garlic scapes and snap peas while the plant’s roots taste like horseradish. To quote the USDA, let’s eat it to beat it!

This spring, an Americorps team joining FLOW will be removing garlic mustard from the Sawmill Wetlands, the Stratford Ecological Preserve, and the Methodist Theological School of Ohio to combat the spread of the invasive non-native species in the Olentangy watershed. To learn about other invasive species in Ohio and what is being done to control them, check out FLOW’s website or the Ohio Invasive Plants Council’s website.

Cover photo: FLOW volunteer pulling garlic mustard at Sawmill Wetlands (pre-COVID). 

Fungi of the Olentangy

To start, this article will mostly be about fungi that grow along the Olentangy rather than the fungi that grow in it. There are fungi that play important roles in decomposing submerged leaf litter and wood, and some that are major parasites of aquatic animals, but these are mostly microscopic and unlikely to be encountered unless you really set out to find them.

So, what are fungi? If you have come across old enough biology textbooks, you will have learned that fungi are a sort of plant. They are vaguely plant-like, but fungi are now considered to belong in their own kingdom more closely related to animals than any other major group of organisms. Like us, fungi “eat”, but they “eat” by dumping enzymes into or around the things they grow on rather than doing this in a specialized digestive tract within their bodies.

Fungi play three main roles in our environment, and those are decomposer, mutualist and parasite. Some fungi combine these roles, or play some other stranger role, but for the most part, the fungi mentioned here will fit into one of these three major ecological categories.

Most of the fungi that grow along the Olentangy are decomposers of wood, leaves, and other plant materials. Fungi are the most effective wood decomposers in our forests, and without them, our forest floors would have much thicker layers of fallen twigs and branches. Many of the major wood decomposing fungi produce mushrooms, and these mushrooms are then fed upon by animals, cycling nutrients from dead plants back into our ecosystems. Squirrels, deer, box turtles and many sorts of insects and other invertebrates use fungi as a major food source. Humans too. Some of you may know one or two of the Ohioan variety who feed on morels (Morchella species) in the Spring.

What exactly is a mushroom then? In the broad sense of the term, a mushroom is a spore-producing structure of a fungus that can be seen with the naked eye and the organism that produces it. Fungi are made up of microscopic, thread-like cells called mycelium, and most of this mycelium forms networks within whatever the fungi are growing on and are usually difficult to observe without a microscope. When you see a mushroom growing on a log, the portion you are observing is part of a much larger organism spread out within this log.

When the Olentangy floods its banks and leaves behind piles of woody debris, the sticks within these piles contain the mycelium of hundreds if not thousands of species of fungi, some of which will form mushrooms when the environmental conditions are right. This fungal “rafting” is one of the major ways that fungi can spread along the Olentangy along with spreading by spores.

Cerioporus squamosus

Cerioporus squamosus, a common wood decomposing mushroom along the Olentangy. Photo by Ellie Nowels.

One especially common wood-decomposing mushroom species in our area is Cerioporus squamosus, commonly known as the “dryad’s saddle” or “pheasant back”. These produce large shelf-like mushrooms on large fallen logs, dead stumps, and on the dead portions of living trees. The tops, or “caps”, of these mushrooms are brown and have darker brown scales on them that make a pattern somewhat like that of the feathers on a pheasant’s back, hence the common name. The underside of the cap contains many off-white pores where the spores are produced.

Cerioporus squamosus is edible and it often begins before morels do in the Spring. It is not as flavorful as morels, but still perfectly edible when young and tender. It has been eaten by many disappointed morel hunters.

Many of the more sought-after edible mushrooms in Ohio are species that form mutualistic relationships with tree roots. These species produce meshes of plant root tips and fungal mycelium known as “mycorrhizae” where the trees provide carbohydrates to the fungal partner and the fungi provide water and vital minerals to the tree partner. Many sorts of tree in Ohio form mycorrhizae with mushroom-forming fungi, including oaks, hickories, beech, basswood, pines, and spruce. In the floodplains of the Olentangy, the most important mycorrhizal tree species is the cottonwood, although its mushroom partners are mostly either very small or potentially poisonous. There is a greater diversity of mushrooms that form mycorrhizal relationships as you head further from the Olentangy and uphill. The oak-hickory ridge tops along the Olentangy are a great place to see a wide diversity of mushrooms in the Summer and Fall.

One of the more common and charismatic mycorrhizal that grows in our forests from mid-Summer to the early Fall is Cantharellus lateritius, the “smooth chanterelle”. It forms mycorrhizal relationships with hardwood trees and produces bright orange trumpet-shaped mushrooms with caps that have a central depression and an underside that is either smooth or has blunt ridges. It often fruits in large quantities and stands out well against the brown and green of the forest floor. It has a faint fruity odor and has a meaty texture. I have also seen it being eaten by box turtles several times in Central Ohio.

Cantharellus lateritius

Cantharellus lateritius, the “smooth chanterelle”, a common edible mushroom species in our hardwood forests. Photo by Django Grootmyers

The third major ecological category of fungi, the parasites, are very diverse, although mostly microscopic. There are parasitic fungi that parasitize almost every sort of life form there is. The are fungi that are parasites on plants, animals, and even other fungi. There are even fungi that are parasites on other parasitic fungi, and these are known as hyperparasites. Some of the stranger parasitic fungi are those that parasitize insects, also known as entomopathogens. These invade the tissues of the host insect and kill them before bursting through their exoskeleton to produce a fruiting structure. There are some that are able to take control of the host insect’s brain and make it climb to a more suitable place for the fungus to produce spores before killing it.

Massospora cicadina

Massospora cicadina, the “flying saltshaker of death”, a bizarre parasite of cicadas that replaces the host’s abdomen. Photo by John Plischke III.

One especially bizarre example is Massospora cicadina, the “flying saltshaker of death”, which parasitizes cicadas and eventually replaces the host’s abdomen with its own spore producing surface before killing it. The cicada continues to fly around with its abdomen missing “shaking” spores into the air as it goes and will even attempt to mate with other cicadas in this state, further spreading the fungal infection to other cicadas. The fungus produces cathinone, an amphetamine that is also present in the qat tree used as a stimulant in the Arabian Peninsula and the Horn of Africa. The cathinone apparently makes the cicada unaware of its missing body parts and allows it to continue to fly around before the fungus completely burns it out and kills it.

There are many bizarre and widely varied species of fungi that grow in our area, and my current best estimate is that there are at least 5,100 species of fungi in Ohio. Because of this, if you look closely at the fungal diversity around you as you walk through our woods, you will very often come across something you have never seen before, maybe even something nobody else has ever noticed before. For those wanting to learn more about mushrooms in Ohio, the Ohio Mushroom Society puts on several yearly mushroom events, or “forays”, where you can have the mushrooms you find identified by mushroom experts and just have a lot of fun in the woods. For more information about the Ohio Mushroom Society, refer to their website at https://ohiomushroomsociety.wordpress.com/.

Django Grootmyers
Student research assistant to Dr. Jason Slot
Department of Plant Pathology, Ohio State University, Columbus, Ohio 43210
dgrootmyers@gmail.com

The Lower Olentangy Greenspace Plan is now available

The Olentangy Watershed is currently home to 283,000 people. The Mid-Ohio Regional Planning Commission (MORPC) expects this number to nearly double to 500,000 by 2050. With more people comes more development and more impervious surface. Maintaining a healthy watershed with this growth is a challenge that requires careful planning and coordination among several key stakeholders. FLOW’s Greenspace Plan is the first step of such coordination, ensuring that we are protecting and restoring the right places.

FLOW received funding from The Columbus Foundation to produce the Lower Olentangy Greenspace Plan. This was designed as a proactive planning effort to target the protection of high quality areas for the protection of the Olentangy watershed, while accommodating people’s needs for access to greenspace. The Greenspace Plan illuminates the value of accurately inventorying our existing natural resources, provides a framework to educate our citizens, and serves as a tool for prioritizing future efforts and making informed decisions.

The value of greenspace must be recognized for the ‘eco-services’ it provides. We can no longer think of greenspace as “just undeveloped” land. Greenspace provides very quantifiable benefits that cannot be replaced by any other means. Greenspace provides habitat, biodiversity, clean air, healthy places to recreate and heal, and mitigates heat island effects.

The Greenspace Plan assigned scores to land using 22 variables related to ecological resources and opportunities for restoration and protection. The scores were a result of weighting each variable and adding the weighted values of all variables for a particular piece of land. This was completed throughout the entire Lower Olentangy watershed. These were then categorized into five Greenspace Tiers, where Tier 1 represents those areas most important for water quality protection, and Tier 5 displaying the least opportunity for water quality protection. However, greenspace could exist in any of these tiers. Protection of these spaces may be more important within Tiers 1 and 2, whereas greenspace may need to be crated in Tiers 4 and 5.

This Greenspace Plan has been summarized in a report, and the results can be freely accessed here. We hope our partners take advantage of this Greenspace effort for future planning. According to the Trust for Public Lands, the average greenspace in the 100 largest cities in the U.S. covers 15% of their total area. Currently, the Olentangy only has 9% greenspace, and that is without the development anticipated by 2050. Now is the time to plan appropriately for adequate protection of our waterways, and FLOW is now turning its attention to using our Greenspace Plan to prioritize our restoration efforts.

GreenSpace Plan 2020

GIS data page

May Volunteer of the Month: Joe Bevan

Our volunteer for the month of May is Joe Bevan!

Joe started volunteering with FLOW senior year of high school in the Water Quality Monitoring Program.  He has continued to volunteer with FLOW on many different projects throughout the years. Joe was critical in assisting FLOW with creating the Lower Olentangy Greenspace Plan.

Joe says he volunteers with FLOW for the trees and for the bugs and especially for the people.  If you have had the honor of volunteering with Joe, you know his drive to complete a task, as well as his sense of humor, keeps one motivated when planting hundreds of trees in one morning!

Joe has a Bachelor of Science degree in Environmental Science from The Ohio State University and works at AEP as a GIS Specialist.  

FLOW could not accomplish all we do without great volunteers like Joe! 

Quart-sized Planting Pot Round-up!

Planting for Mother’s Day….or later in the week????    Please save your quart-sized (3-4 inch) pots for us!!!!

We will collect next Sunday, May 17 from 2-4 in the alley behind the FLOW office (3528 N. High St). Please come to the alley out back and stay in your car. We will have a table set up so you can just drive up, drop off, and keep going!

Thank you so very much for supporting us!