Released: February 01, 2005

Toxic Plants Abound in Homes, Landscapes

MANHATTAN, Kan. – A rural homeowner trimmed some rapidly growing yews last year and threw the resulting clippings over a fence that separated yard from pasture. After all, shrub trimmings are organic, so should degrade and enrich the soil.

As can happen with “shoulds,” however, the result at this Sedgwick County site wasn’t pasture improvement. Several steers decided the yews’ bright evergreen trimmings looked like lunch. They died from poisoning.

“Yews are toxic to children and pets, as well. As a matter of fact, yews are one of our most toxic landscape plants,” said Ward Upham, Kansas State University Research and Extension horticulturist. “But, poisonous plants in our homes and yards are far more common than most people would think.”

Fortunately, toxic plant parts often taste bad.

“You can’t depend on that, though – particularly if a toddler who tastes everything might be around,” Upham said. “In that case, you need to do some planning. You can choose not to buy. You can dispose of the potentially hazardous plants you have. Or, you can create barriers to what’s poisonous.”

Hazardous plants vary in just how toxic they are. They also vary in number of poisonous parts.

Upham listed the following, however, as among the plants that merit caution around humans:

* HOUSEPLANTS

Chinese Evergreen

anthurium (all parts)

aloe (sap, if eaten)

calla lily (all parts)

croton (seeds, leaves, stems)

crown-of-thorns (milky sap)

dieffenbachia (all parts)

elephant ear (leaves, fruits, sap)

philodendron (all parts)

* LANDSCAPE PLANTS

azalea (leaves, flowers)

black locust tree (all parts)

Boston ivy (berries)

boxwood (leaves, twigs)

buckeye (leaves, shoots, bark, flowers, seeds)

burning bush (all parts)

ornamental cherry (leaves, twigs, bark, seeds)

clematis (leaves)

elderberry (roots, stems, bark, leaves, unripe fruits)

English ivy (all parts)

golden chaintree/Laburnum (all parts)

holly (berries, leaves)

horse chestnut (all parts)

hydrangea (leaves, buds of some species)

Kentucky coffeebean tree (seeds, fruit pulp, leaves, twigs)

oak tree (acorns, leaves, young shoots of some species)

poison sumac (all parts)

privet (all parts)

rhododendron (leaves, flowers)

Virginia creeper/woodbine (berries)

yew /Taxus (all parts except fleshy red seed cover)

wisteria (all parts)

* FLOWERING ORNAMENTALS

caladium (all parts)

cardinal flower (all parts)

castor bean (seeds, leaves)

daffodil/narcissus (all parts)

flowering tobacco/Nicotiana (leaves, flowers)

four-o-clock (roots, seeds)

foxglove (all parts)

hellebore/Christmas rose (all parts)

iris (all parts)

lantana (unripe fruits, leaves)

larkspur/delphinium (all parts)

lily of the valley (all parts)

lupine (all parts)

monkshood (all parts)

poppy (all parts except ripe seeds)

snowdrop (bulb)

spurge/cushion spurge/Euphorbia (milky sap)

star-of-Bethlehem (all parts)

sweet pea (seeds, seedlings, pods)

tulip (bulbs)

* FOOD-PRODUCING PLANTS:

apple (bark, leaves, seeds)

apricot (bark, leaves, seeds, pits)

avocado (leaves, unripe fruit, bark, seeds)

cherry (bark, leaves, seeds, pits)

nectarine (bark, leaves, seeds, pits)

peach (bark, leaves, seeds, pits)

pear (bark, leaves, seeds)

plum (bark, leaves, seeds, pits)

potato (green skin, buds, sprouts on tubers, “fruits,” foliage)

rhubarb (leafy blade, not the leaf stalk)

Upham said livestock and pet owners can get a more specific view of what’s toxic for animals from a Purdue University Web site: http://www.vet.purdue.edu/depts/addl/toxic/cover1.htm .

“Ironically, they’re often the plants that landscape-wrecking deer will leave alone, too – which can lead to some difficult, least-risk kind of decisions,” he said.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Kathleen Ward
kward@oznet.ksu.edu
K-State Research& Extension News