Cogongrass: An Invasive Weed In Georgia

- The Bugwood Network, The University of Georgia

Cogongrass (Imperata cylindrical) is a perennial colony-forming grass that grows up to 3 feet tall. Leaves have an off-center and whitish midrib and rough edges. Sharp, branched, white rhizomes help identify this plant. It is best identified by the large fuzzy panicle of flowers and seeds,  giving the plant a cottony or silky look. Flowering occurs in late spring.

A native to Southeast Asia, it was first introduced into the southeastern Untied States in the early 1900’s. It was initially planted for forage and erosion control; however it is unpalatable for livestock and not well suited for erosion control due to its aggressive behavior. Currently it is found in the southeastern United States and is sparse in South Georgia.

It is an extremely aggressive invader with the capability to invade a range of sites. It forms dense mats that exclude all other vegetation, leading to its inclusion on the federal noxious weed list. It spreads both by rhizomes and winddispersed seeds. Infestations often occur in circular patterns.
It is very flammable and creates fire hazards, especially in winter.

Congongrass is a federal noxious weed and any occurrence should be promptly reported. The recommended herbicides for control are a foliar spray of Arsenal AC, Glyphosate, or a combination of both.

Poisonous Plants And Mushrooms In The Landscape

La Rochefoucauld said that “To eat is a necessity, but to eat intelligently is an art.” Nearly everybody in his or her life has had at least a small desire to get out of the fast lane and resort back to a simpler way of life. Not the least of these instincts are the pleasure of eating foods provided by nature and becoming, at least for a day, independent of the supermarkets. Edible wild plants and mushrooms grow in our woodlands, marshes, fields, pastures, and in our own landscapes. Some of the best tasting and healthy foods are available “free” for the eating, provided you know which plants and mushrooms are edible!

One of our early cave dwelling ancestors encountered a pretty cluster of mushrooms on the ground and asked:

  • What can I do with it?
  • Will it feed me?
  • Will cure my ills?

An intrepid ancestor ate it and promptly died. Fear of poisonous plants and mushrooms is traceable to stories like this.

The term “POISONOUS” used in this article does not imply that the plants or mushrooms are deadly. Plant and mushroom poisoning can vary from dermatitis to a minor stomach upset, hallucinogenic ‘trips’, or a rather painful, protracted death. There are a number of variables that determine how severe the poisoning symptoms maybe, such as the plant or mushroom species and the person’s age, weight, and health status in relationship to the quantity of the plant or mushroom ingested. Also impacting the severity of the symptoms is the form of plant or mushroom at the time of ingestion (i.e., cooked versus raw, fresh versus aging, etc.).

Don’t be paranoid. Build your knowledge of plants and mushrooms and whether or not they are toxic or edible. Garden centers, nurseries, florists, and Cooperative Extension can assist in plant identification. Plant samples taken in for identification purposes should be fresh and include leaves, stem, flowers, and fruit. For mushrooms, take in the entire fruiting body from cap to base (the part in the ground).

POISONOUS PLANTS
Most of us are familiar with common poisonous plants that cause skin irritation such as Poison Ivy or Poison Oak. More than 100 species of common landscape plants in Georgia, however, can cause illness or death. Many ornamental plants found in the landscape were selected from wild populations due to their foliage, flowers, and scent. In many cases, little or no consideration was given to plant toxicity. Landscape plant toxicity is good in once sense since many herbivores, such as deer and rabbits, and insects, like Japanese beetles, tend to avoid them.

In the vegetable garden, many plants also contain toxins. For example, the stems and leaves of tomatoes, peppers, eggplant, and potatoes (members of the Nightshade family) contain alkaloid toxins that can cause liver damage. The edible fruits of tomatoes, peppers, and eggplants and tubers of potatoes do not contain toxic levels of these alkaloids. Potatoes, however, may turn green in response to light and become toxic. Another member of the Nightshade family, tobacco contains the alkaloid nicotine.

Most adults would not knowingly eat leaves, stems, roots, or fruits from an unknown plant in our pastures, lawns, or forests. This does not apply to our children, livestock, or pets.

Children love plants and love to put things into their mouth just for a taste. Teach them not to eat any plant unless they have permission from a knowledgeable adult and don’t decorate the table with poisonous plants.

Since pets and livestock can’t read, always provide them with plenty of water and palatable feed. Walk the lawn, pasture, and forest to identify potentially poisonous plants. Your local veterinarian can help you learn about local plants that may harm your pets or livestock.

The physiological effects that generally categorize plant poisonings are:

  • Abortifacient and Reproductive Toxins: Substances that can cause mutations, birth defects, abortions, and infertility or sterility. Broom snakeweed (Gutierrezia sarothrae) is an example.
  • Cardiac Glycoside-Containing Plants: Cardiac glycosides primarily affect cardiovascular, neurological, and gastrointestinal systems and can be found in foxgloves (Digitalis purpurea).
  • Cyanide or Prussic Acid-Containing Plants: Prussic acid, cyanide, or hydrocyanic acids are all terms relating to the same toxic substance. It is one of the most rapidly acting toxins. Chokecherry (Prunus spp.) is an example.
  • Gastrointestinal Irritants and Toxins: The juice, leaves, roots and seeds of plants containing gastrointestinal irritants can produce stomach cramps, nausea, vomiting, and diarrhea. Examples are aloe, daffodils, and geraniums.
  • Alkaloid-Containing Plants: Alkaloid toxicity may result in moderate to severe liver damage. Gastrointestinal symptoms are usually the first sign of intoxication, and consist predominantly of abdominal pain with vomiting. Death may ensue from 2 weeks to more than 2 years after poisoning. Groundsel (Senecio riddellii) is an example.
  • Neurotoxic and Myotoxic Plants: All parts of the plant contain toxic steroidal alkaloids that cause cardiovascular failure. An example is Jimson Weed (Datura stramonium).
  • Oxalate-Containing Plants: Toxic oxalates form insoluble salts that crystallize and damage vessels and renal tubular epithelium and can be found in Larkspurs (Delphinium spp.).
  • Photosensitizing Plants: The poisonous compound in the plant, hypericin, reaches the skin from an internal route (stomach to blood to skin) where it sensitizes the skin to sunlight. Pigments in the skin shield colored skin from sunrays so that only white or unpigmented areas are affected. St. Johnswort is an example.

For a complete listing of Georgia’s poisonous plants including toxic plant parts and symptoms, go to UGA’s Horticultural Fact Sheet “Poisonous Plants in the Landscape” written by Robert Westerfield and Gary Wade at: pubs.caes.uga.edu/caespubs/horticulture/h-00-056.pdf .

SOME TOXIC ORNAMENTAL PLANTS *Reported to be fatal when ingested in quantity
Common Name Botanical Name Plant Part Common Name Botanical Name Plant Part
Air Potato Dioscorea bulbifera Raw fruit English Ivy Hedera helix Leaves, stem, fruit
Algerian Ivy* Hedera canariensis All parts Holly Ilex spp. Berries
Allamanda Allamanda spp. All parts Honeysuckle, Japanese and Trumpet* Lonicera japonica, Lonicera sempervirens All parts
Amaryllis Amaryllis spp. Bulbs & seeds Hydrangea, Oakleaf Hydrangea, Bigleaf Hydrangea, Smooth Hydrangea quercifolia, H. macrophylla, H. arborescens Leaves, bark
American Arborvitae* Thuja occidentalis Leaves Impatiens, balsam Impatiens spp. Leaves, stem, root
Angel’s Trumpet* Datura spp. All parts Iris Iris spp. Underground stems
Anise-tree* Illicium floridanum, Illicium anisatum Leaves Jack-in-thepulpit Arisaema spp. All parts
Azalea Rhododendron spp. All parts Juniper Juniperus spp. Berry-like seeds
Barberry Berberis spp. All parts Lantana* Lantana spp. Fruit
Black Locust Robinia pseudoacacia Bark, seeds Lily—of-thevalley Convallaria majalis All parts
Boxwood Buxus sempervirens Leaves Lilies* (Rain Lily, Atamasco Lily, Easter Lily) Zephyranthus spp. All parts
Buckeye Aesculus spp. All parts Mahonia Mahonia spp. All parts
Caladium Caladium bicolor All parts Mimosa Albizzia spp. All parts
Calla-lily Zantedeschia spp. All parts Morning Glory Ipomoea spp. Seeds, root
Castor Bean Ricinus communis Seeds Mountain Laurel* Kalmia latifolia Leaves, twigs, flowers
Century Plant Agave americana Leaves Oleander* Nerium oleander L. All parts
Clematis Clematis spp. All parts Ornamental Tobacco* Nicotiana spp. All parts
Crinum Lily Crinum spp. Bulb Periwinkle (vine) Vinca minor All parts
Delphinium* Delphinium spp. All parts Plumbago Plumbago spp. Leaves, stem
Elephant Ear* Colocasia esculenta All parts Privet Ligustrum spp. Fruit
False Indigo* Baptisia spp. All parts Sago Palm Cycas revolute Seeds, root, trunk pith
Firethorn Pyracantha spp. Berries Sweet shrub Calycanthus floridus Seeds
Four-o-clock Mirabilis jalapa Root, seeds Trumpet Creeper Campsis radicans All parts except fruit
Ginkgo (female) Ginkgo biloba Fruit Wisteria Wisteria spp. Pods, seeds
Gloriosa Lily Gloriosa superba All parts Yew* Taxus spp. Berries, foliage

POISONOUS MUSHROOMS
Wild mushrooms are found in all parts of the Georgia landscape: pastures, lawns, forests, and organic mulch of all types. Also on stumps, living trees, and in the home, particularly in basements, plaster board walls, and flower pots. Mushrooms can be found throughout the year, mostly early spring through the fall, if temperature and moisture are suitable for their fruiting.

Mushroom poisoning is caused by the consumption of raw or cooked fruiting bodies (mushrooms or toadstools). The term toadstool is from the German Todesstuhl or Death Stool and is generally applied to poisonous mushrooms. For individuals, who are not expert at mushroom identification, there are no general rules to distinguish between edible mushrooms and poisonous toadstools. Old wives tales notwithstanding, toxic mushrooms cannot be made nontoxic by cooking, canning, freezing, or any other means of processing. The only way to avoid poisoning is to avoid ingesting toxic species.

Mushroom poisonings in the United States commonly occur among:

  • Expert and novice wild mushrooms hunters.
  • Among recent immigrants that eat wild mushrooms that resemble those of their native land.
  • Persons who intentionally consume psychedelic mushrooms.

Accurate figures on the relative frequency of mushroom poisonings are difficult to obtain. The Centers for Disease Control in Atlanta lists 44 cases reported between 1976 and 1981. The number of unreported cases is unknown. Poisonings tend to be grouped in the spring and fall when most mushrooms are in the fruiting stage. As Americans become more adventurous in their mushroom collection and consumption, poisonings are likely to increase.

About 98% of all “wild” mushrooms are not poisonous but about 1% are dangerous (1% are woody or too small to attract any interest). Wild mushrooms should not be eaten unless YOU personally can identify them as safe. Do not rely on the identification any wild mushroom by a neighbor or “expert” amateur mushroom hunter. Remember that “specialists” or “experts” have also been poisoned.

The physiological effects that generally categorize mushroom poisonings are:

  • Protoplasmic Poisons: Poisons that result in generalized destruction of cells and with amatoxins results in irreversible liver and kidney damage that is fatal.
  • Neurotoxins: Compounds that cause neurological symptoms such as profuse sweating, coma, convulsions, hallucinations, excitement, depression, and spastic colon.
  • Gastrointestinal Irritants: Compounds that produce rapid, transient nausea, vomiting, abdominal cramping, and diarrhea.
  • Disulfiram-like Toxins: Produce no symptoms unless alcohol is consumed within 72 hours after eating them, in which case a short-lived acute toxic syndrome is produced.

To identify unknown wild mushroom species, I would recommend the Federal Food and Drug Administrations website at www.cfsan.fda.gov/~mow/chap40.html. Since the retirement of Dr. David Porter, UGA’s Plant Pathology Department is ill prepared to identify questionable mushrooms species.

Georgia is home to several species of mushrooms that could cause death if only a single mushroom is eaten. Two such deadly species are the Destroying Angel, Amanita virosa, and the Autumn Skullcap, Galerina autumnalis. Some mushrooms that are not toxic under normal conditions can have a toxic reaction if consumed with alcohol.

SOME TOXIC MUSHROOMS  *Mushrooms contain protoplasmic toxins
Common Name
Botanical Name
Common Name
Botanical Name
Slender Death Angel* Amanita tenuifolia Autumn Skullcap* Galerina autumnalis
Death Angel* Amanita bisporigera Browning Parasol* Leucoagaricus brunnea
Fool’s Mushroom* Amanita verna Little Brown Mushroom (LBM)* Lepiota josserandii, L. helveola, L. subincarnata
Destroying Angel* Amanita virosa Green Gill Chlorophyllum molybdites
Deathcap (White cap)* Amanita phalloides Gray Pinkgill Entoloma lividum
Deathcap (green cap)* Amanita phalloides Tigertop Mushroom Tricholoma pardinum
Death cap (Yellow cap)* Amanita phalloides Jack O’Lantern Omphalotus olearius
Cleft Foot Deathcap* Amanita brunnescens Naked Brimcap Paxillus involutus

IN CASE OF A POISON EMERGENCY
In the event of a poison emergency call the Georgia Poison Center any time, 24 hours a day, 7 days a week:
In Metro-Atlanta Call: 404-616-9000
Outside of Metro-Atlanta Call: 1-800-282-5846
Teletype for the deaf and hearing impaired only: TTD 404-616-2987
If the poisoning occurs and the person is having trouble breathing, experiencing seizures, or will not wake up, Call 911 immediately.
Be prepared to give the attending physician:

  • The name of plant or mushroom, if known, or description (save uneaten parts).
  • How long ago it was eaten.
  • How much and which parts were eaten.
  • Age of individual.
  • Symptoms.

If hospitalization is required, take a portion of the suspect plant or mushroom with you for positive identification

Hemlock Wooly Adelgid Alert

from the Lumpkin Coalition

(Ed. Note: Lumpkin Coalition is a non-profit organization in Lumpkin County.)

Our forests are threatened with the loss of our native hemlocks, eastern hemlock (Tsuga canadensis) and Carolina hemlock (T. caroliniana). They are being decimated by the hemlock woolly adelgid (HWA), a tiny, aphid-like insect accidentally introduced to the east coast from Asia in the 1950s. The HWA attaches to the stems at the base of the needles making an incision and draining the tree of its sap. The tree often dies within just a few years. The devastation from this tiny parasite has spread from Virginia, north to Maine, and then south to Georgia. Infestations of the HWA have already reached Rabun, Towns, Habersham, Union, White, Fannin, Whitfield, and Lumpkin Counties and are traveling fast. If nothing is done to combat HWA, more than 80 percent of our hemlocks may die in the next six to 12 years.

The Lumpkin Coalition, which is working to educate the public about this threat, is warning us to be on the lookout for infestations in hemlock trees and to take action if this pest is found. Their Hemlock Hotline website link (http://lumpkincoatliton.org/hotline.htm) offers tips and information about the HWA threat.

During the months of March through June, the “crawlers” are active and most easily seen on the underside of hemlock branches. They look like tiny cotton balls at the base of the needles. In one year, one bug can produce as many as 90,000 offspring. In as little as two to three years, your hemlocks can die. More information about the hemlock woolly adelgid, as well as photos, can be found at the Lumpkin Coalition website, www.lumpkincoalition.org.

Fortunately, the Lumpkin Coalition says there are steps you can take to prevent this calamity:

  1. If you have a few small trees (up to 8 feet tall), you can spray them with insecticidal soap, horticultural oil, or any insecticide that kills aphids. These chemicals are available at most hardware stores. Be sure to coat the whole tree, including the underside of all limbs and leaves. The best times to treat them are April to June and October.
  2. If you have just a few large trees on level ground, you may use Bayer Advanced Tree and Shrub insect control as a soil drench. This product is available at most hardware stores. Follow the directions on the label carefully.
  3. If you have many large trees and want to keep your costs down, you may borrow a Kioritz Soil Injector from the Forestry Commission in these counties: Lumpkin, Union, Habersham, and Towns. You will have to pay a $250 refundable deposit, and staff members will show you how to use the injector and tell you where you can purchase the chemicals for it.
  4. If you and your neighbors want to join forces to protect large numbers of trees, you may call Scott Griffin, the Forestry Commission’s Forest Health Specialist. He will come to your group and provide training on how to use the injector and how to plan your preservation efforts. Scott can be reached at 770-531-6043.
  5. If you have limited time and/or want to avoid handling the chemicals involved in treatment, you may call a professional. There are two individuals in North Georgia who do this kind of

work at a reasonable cost and are willing to travel to your property: Kevin Johnson of Grow It Green in Blue Ridge at 866-883-2420 and Mark Shearer in Dahlonega at 706-864-4787. These individuals will inspect your trees and give you an estimate for treating them. They will also
advise you on when you will need to re-treat your trees, since the chemicals are effective only for up to three years. For more information about the hemlock woolly adelgid and the Lumpkin Coalition, visit their website.

A Bit of Dirt – Summer 2008

The full pdf copy of this edition is available here.

PRESIDENT’S MESSAGE – by John Atkinson

ADVANCED MASTER GARDENER TRAINING
There is so much to learn and so little time. Marco Fonseca, State MG Coordinator, and others at the University of Georgia have put together the
Advanced Master Gardener Training Program to provide continuing education for the Georgia Master Gardener. Participants in the program found it a rewarding experience and well worth the effort. UGA recognizes your participation with a certificate that can be placed in a prominent location at your home or office.

What’s an advanced class like? It is more than a refresher of the training you have already experienced as an intern. It has much greater depth
and specificity. The instructors are highly qualified in their field and the presentations are designed to be of timely interest and educational importance to the Master Gardener. There is a pre-class exam to determine your level of knowledge before the class. An exam at the end of the class to determines how much you’ve learned. The exams are fairly straightforward so there is no need to panic.

Sign up as soon as you see the announcement in the Georgia Master Gardener Association’s “The Georgia Scoop” newsletter or receive an email notice from Krissy Slagle, State MG Program Assistant, or Kathy Parent of the Gwinnett Extension Office. All the classes have a limited enrollment and fill up quickly. The topic and program description provide an idea whether or not the training class would of interest to you. The training definitely builds your confidence and increases your horticultural knowledge. The knowledge gained in these classes will make you a
better Gwinnett County Master Gardener.

If you can’t participate in the Advanced Master Gardener Training Program, spend some time reviewing the material in the Master Gardeners
Handbook and the Pest Management Handbook. This will increase your ability to contribute to the knowledge of the citizens of Gwinnett County who rely on the Gwinnett County Master Gardeners for sound, reliable guidance.

Other articles in this issue:
Hemlock Wooly Adelgid Alert – from the Lumpkin Coalition
Poisonous Plants And Mushrooms In The Landscape – By Dan Willis
Cogongrass: An Invasive Weed In Georgia – The Bugwood Network, The University of Georgia