UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail:  dfculbert@ifas.ufl.edu

April 19, 2007

Feature Article - for release the week of  April 22, 2007

Dan Culbert - Extension Horticulture Agent

 

Beware of Poisonous  Pasture  plants

Welcome to the drought.  We hope area homeowners are adjusting to the two-day a week watering schedule, and are being careful not to add stress to their Florida Yards. Call us if you need landscape advice on dealing with the drought.

 

Our office has had quite a number of office visitors that have reminded us of another drought related issue.  Everyone knows that Okeechobee beef and dairy producers are very dependent on pastures for animal feed.  The forecast is for rapidly vanishing grass supplies.

 

While recent rains have greened up the grass a little bit, they have also perked up a few other pasture plants that are usually ignored by livestock.  And they are ignored for good reason – they are poisonous.  But with less grass to eat, hungry cattle and horses will sample some of these problem plants, sometimes with disastrous results.

 

Today’s column is designed to introduce a few of the offending weeds that have been noticed by area ranchers and by Pat and Pat – our county’s Livestock and Dairy Agents.  Many more local poisonous plants could be noted and will  be brought to your attention as they become a problem.

 

*       Black Nightshade (Solanum nigrum) is also called common nightshade, poisonberry, garden nightshade, and sometimes deadly nightshade. It grows from seed each year, and has alternate, simple, smooth leaves.  Clusters of small white or pale violet flowers have five petals that make clusters of dull black berries.  This is a relative of peppers, tomatoes, eggplants and potatoes, which can also cause similar poisoning symptoms if livestock eat these vegetable plants.  Symptoms of poisoning include nausea, vomiting, salivation, drowsiness, abdominal pain, diarrhea, weakness, respiratory depression; may be fatal.   This plant also hosts pepper weevils and various virus diseases that effect vegetable crops –  other reasons to rid it from your property.   (A related plant called Garden huckleberry looks similar, but it is not poisonous and not likely to be seen in a pasture.)

*       Lantana (Lantana spp.)  There are several species and hybrids of this attractive flowering shrub.  They all have similar features which should help distinguish them.  They are upright spreading shrubs usually 1-3 feet tall.  Leaves generally have a sandpapery feel and grow in pairs.   The flower clusters are often multicolored: pink, yellow, white, orange and red are common with local non-native Lantana found in pastures. (Ornamental types might also be lavender or deep red flowers.)  Flowers produce small clusters of green berries that mature to bluish black. Not only do the leaves cause skin rashes, eating the fruit, foliage or stems has caused gastroenteritis, diarrhea, jaundice, photosensitivity, ulcers at the nose and mouth, peeling skin and, potentially, death.

*       Milkweeds (Asclepis spp.) are common in area landscapes and pastures, and have become popular with gardeners as butterfly attracting plants.   There are several dozen natives and a couple of introduced species of milkweeds in Florida.  They generally are upright multi-stemmed annual plants with pairs of leaves that usually lack leaf stalks.  Break a stem or leaf and milky white sap will bleed from the wound.  Flower colors can be white, yellow, orange, or red in color.  Fruits are pods that fill with seed and lots of silky floss which allows the seed to spread with the wind.  Symptoms from eating these plants in livestock include dizziness, tremors, fever, labored breathing, and if enough is eaten, can be fatal.  And for the humans, add skin rashes to the milkweed symptoms.  

*       Perilla Mint (Perilla frutescens) was one of the plants that stumped me this week.  I was able to identify it as a mint.  It has pointed pairs of dull leaves with saw-toothed edges, had clusters of small whitish flowers at the top of the stems, and a distinctive minty odor to the plant.  The Perilla mint also has leaves that are purple on the lower sides.  The rancher that brought it in reported his heifers went under respirator distress and fever.

*       Common Pokeweed (Phytolacca americana) has many common names, including  pokeweed and  pigeon berry.  This succulent perennial herb has green-to-purple stems and a large, fleshy root stock.  Common pokeweed may grow into plants six or more feet tall.  It is found in pastures, fence-rows, fields, and wooded areas. Clusters of flowers at the stem ends have one-quarter inch flattened berries that turn purple black at maturity.  Juices from these fruit are used as a natural plant dye, and there are reports that the plant can be cooked as greens if done at the right time.  However, I would advise against consumption of Pokeweed, as it has been known to cause immediate burning inside the mouth, and has lead to gastroenteritis with cramping, diarrhea, and convulsions.

*       Rattlebox is a common name give to several species of Crotalaria and to another member of the bean family, Sesbania punicea. These leafy annual herbs are members of the pea or bean family.  In Crotalaria, broadly rounded leaves grow in groups of three and clusters of yellow pea-shaped flowers grow inside the stems of the plant.  The Sesbania Rattlebox has reddish colored flower clusters and leaves with a more feathery in appearance. The Rattleboxes produce a pod that is filled with seeds, and when dry, the pods rattle in the wind – the source of the name. When consumed by livestock, Crotalaria may result in bloody diarrhea, jaundice, rough hair coat, unthriftiness, and weakness. Sesbania produces delayed effects of difficult breathing and irregular pulses.

Preventing Poisoning

Prevention of poisoning by toxic plants includes providing an adequate quantity of quality forages; avoiding situations of overstocking; and implementing good pasture management practices to eliminate toxic plants and situations leading to toxic plant poisoning.

For help with positive weed ID, check the references on our website or bring in a sample to our office.  We can also provide University of Florida recommendations for managing these weeds, including those herbicides that are legal to use when managing these pests. 

If you suspect that people have been poisoned by plants, call 9-1-1 immediately, and remember to take a sample of the plant with you to the hospital.   In the case of livestock poisoning, it is highly recommended that a necropsy be done to establish that the animal was affected by plant poisoning.

I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on poisonous pasture plants, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 3 PM on Tuesday afternoons. GO GATORS!

Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.  Florida Cooperative Extension Service / IFAS / University of Florida.  Larry A.  Arrington, Dean Last update: 05/22/2007 .  This page is maintained by Dan Culbert 

references

Ferrell, Jason A. "Showy Crotalaria/Rattlebox"   In: Agronomy News.  UF/IFAS Agronomy Department, 8/2005, p. 7.   http://agronomy.ifas.ufl.edu/docs/August2005.pdf

Florida Poison Information Center. Common Poisonous Plants of Florida.  [website]  Tampa: FPIC, 4/2007. http://www.poisoncentertampa.org/informational/poisonplants.html  

Harrison, Marie  Choose the Right Lantana for Your Landscape.  Tallahassee: Leon County Extension Service, 08/2004. http://leon.ifas.ufl.edu/News_Columns/2004/081504.pdf 

Mayo, Doug and Ferrell, Jason. 2005 North Florida Pasture Weed Control Quick Reference Sheet.  Marianna: Jackson County Extension Service, May 2005.  http://jackson.ifas.ufl.edu/PDF%20Files/05%20Pasture%20Weed%20Field%20Guide.pdf 

Poisonous Plants of the Southern United States [Publication 818].  Univ. of Georgia Extension Service,  1980 (?) . {out of print} http://www.caf.wvu.edu/~forage/library/poisonous/index.htm 

Rae, Owen  and Tyree, Allen.   Florida Cow-Calf Management, 2nd Edition - Maintaining a Healthy Herd. [AN120] Gainesville:  UF/IFAS Extension Service, 1/2002.  http://edis.ifas.ufl.edu/AN120

Sellers,Brent, Ferrell, Jason and Rainbolt, Curtis. Common Pokeweed  [SS-AGR-123]  Gainesville:  UF/IFAS Extension Service, 11/2006.  http://edis.ifas.ufl.edu/AG254

 

In response to an email about local plants that would be a problem to horse owners, here is a response:

UF is working on some good on-line references for plants poisonous to livestock but they are not yet up.  In the meantime, here are some additional links that I have not added to the references at the bottom of my news article.  They were suggested by some locals knowledgeable about this issue: 

http://www.floridahorse.com/poisonplants.html - produced by University of Miami, it also has a link to a site at Cornell University.

 http://extension.oregonstate.edu/linn/content1/poisonplants.php  

The problem with these out-of state links is that they do not take into account what grows here.   I’m slowly working on a local plant list, but it too is still under construction.

 If you see something that you have and can’t ID it, bring in a generous cutting or clump.  And if you have a specific plant that you are considering to add to your Florida Yard, I can tell you if it is known to have poisonous characteristics.