June 14, 2007

BY Marce Lucke,
Victoria County Master Gardener

Edited by Charla Borchers Leon

“These two plants are often mistaken for one another.  The one on the right is poison ivy and the one on the left is Virginia creeper, a non-poisonous plant.  Since poison ivy typically has three leaflets, a good rule of thumb to remember is “leaflets three, leave it be.”
“Poison ivy is closely related to poison sumac and poison oak but visual differences can be noticed.”
How many poisonous plants do you have around your house and yard?  Think again.  You may be surprised!  We should think of poisonous plants as those that cause a rash or cause an allergic reaction, make you ill, or worse, cause death of a pet or even a human.

Some plants have a sap, oil, or surface that causes an allergic reaction to animals and humans.  It is theorized that over time, some plants developed this defensive toxin to repel insects or predators that would damage the plant.  Although some poisonous plants are native, many of these were brought in to our country either by chance or mistake or to be a commercial crop but later turned into invasive pests.

With all the rain this year, there is considerable new weed growth and plant material everywhere – even in your own yard.  Birds and animals also bring in all kinds of seeds and debris.  Any of these could contain poisonous plant parts and cause discomfort or severe illness to you, your pets and family.

Common Poison Ivy

One of the most well known poisonous plants that could be in your yard or weedy area is poison ivy.  Known in the climbing form as toxicodendron radicans, it is closely related to eastern poison oak (toxicodendron toxicarium) and poison sumac (toxicodendron vernix).  People who are sensitive to poison ivy are also sensitive to lacquer and cashew oils. Some people think they are so sensitive to the plant they do not have to touch the leaves but just walk downwind of the plant or be downwind from smoke of burning brush containing the poison ivy and be affected. While this may be true for some, in reality, many get it from unseen methods such as when their pet rubs on the plant leaves and carries back the toxin on its hair and then they play with the pet. Coincidentally, only humans seem to be bothered by this plant. Cattle and horses feed on it and birds eat the berries.

If you are going to be in an area where you might be in contact with the poison ivy be prepared by taking soap and water and towels to clean yourself, the pets and the tools you use and to clean up all clothing and shoes. Carry plastic bags to place anything that comes in contact with the plant and either put them in the trash or wash separately. Do not burn as being downwind may cause problems.  Make sure this material is not added to compost piles.

Nightshade Family Plants

Another plant family – Nightshade (solanaceae) - contains some plants that are poisonous and others non-poisonous that are commercially valuable to us. Non-poisonous plants include potatoes and tomatoes while tobacco and other more toxic plants also fit in the family.  Many plants in this family have a poisonous alkaloid sedative in their seeds such as the jimson weed and members of the datura family, also known to gardeners as angels’ trumpet.

Besides the plants that we commonly know as poisonous there are many that we see every day that can cause a reaction in humans and animals. Of these, mushrooms and oleander can be some of the most deadly, so be sure to warn all about the dangers of these.  Even a few leaves or plant parts may cause death in a small mammal.

Poisonous Plants in the Yard

Other poisonous plants in the yard include amaryllis, calla lily, ranunculus, tulip, buttercup, fig tree (sap), aloe, boxwood, juniper, ferns, helix ivy, ligustrum (many species), lantana, larkspur, datura, all euphorbias, Chinaberry, Chinese tallow, oak sprouts, wild plum (leaves and seed), castorbean, and many grasses. Never chew or place sticks or grasses in your mouth. Even if you can not see it, mold or fungi may be present. At least fifty or more of our common weeds and wild plants are considered dangerous to animals and humans.

Poisonous Plants in the Home

Many household plants are dangerous to children and pets.  A few of these include Easter lily, amaryllis, irises, rubbertree and ficus. All have poisonous parts.  There is a misperception that the holiday poinsettia is poisonous when, in reality, tests have proven it is not.  It is a good rule of thumb, however, to keep pets and children from ingesting any decorative plants as they may cause severe indigestion.  Be especially cautious with these around babies or young children.

To put this knowledge of recognizing poisonous plants into perspective, I quote the words of the nature writer Euell Gibbons from an article in National Geographic in August 1973.  Always follow this basic rule, "Never use any wild plant for food until you have identified it and know it to be edible". Teach your family and friends and train your animals. If the pets still dig in your flowerbeds put netting or chicken wire over your tulips and lily beds. Do not leave houseplants available to indoor pets or babies and give stern warnings to children.

For further information on poisonous plants, contact the County Extension office or visit
http://aggie-horticulture.tamu.edu/PLANTanswers/publications/poison/poison.html on the web on poisonous plants around the home.
Make a log of what plants you have around the home and either try to remove them or inform everyone you love about them.  Keep a watchful eye on the children and pets around your plants and teach them about them.  Remind them that not everything is to eat – some things are just good to look at or to smell. Some plants are grown just for butterflies and birds.  Keep the Poison Control Center phone number handy – 1-800-222-1222- for information.  Also there are many web sites available from universities and colleges that specialize in plant information.  For animals, try the ASPCA hotline number 1-888-426-4435 or click on the poisonous plant link at
www.aspca.org on the web.
Poisonous Plants in the Yard

calla lily
Chinese tallow
fig tree (sap)
helix ivy
ligustrum (many species)
oak sprouts
wild plum (leaves and seed)

At least 50 or more common weeds and wild plants, including poison ivy, are considered dangerous to animals and humans.
More info on poisonous plants at:  http://aggie-horticulture.tamu.edu/PLANTanswers/publications/poison/poisonlinks.html