Toxic outdoor plants
There are many commonly used garden plants that can cause harm to pets or young children if ingested. For instance, lilies can cause kidney failure in cats. Marty DeHart shares valuable information on several potentially dangerous plants that may surprise you.
- Post author By NPT Editorial
- Post date April 27, 2023
- No Comments on Toxic outdoor plants
Plants Featured in this Clip
CONVALLARIA majalis (Lily-of-the-Valley)
NICOTIANA alata
BEGONIA
HEMEROCALLIS (Daylily)
HYDRANGEA
HELLEBORUS (Lenten Rose)
AZALEA
CALADIUM
EUPHORBIA
Gardener Extras
- Begonia's juices and sap contain microscopic poisonous, needle-shaped crystals. The plant is considered mildly toxic, but the roots are especially poisonous.
- The immediate signs of caladium poisoning are pawing at the face and mouth, vomiting, foaming, and drooling. The swelling of the mouth, tongue, and upper airway can produce breathing trouble and difficulty swallowing. This can be quickly lethal to dogs. Immediate medical help is recommended.
- The begonia plant contains large amounts of a substance known as oxalate. Once ingested, the oxalate crystals embed themselves in various tissues causing irritation and can break down into 'oxalic acid', which is also a potent irritant. The cat's body will attempt to avoid further irritation and damage to the digestive tract by vomiting and attempting to dilute the acid with saliva. Eventually, a quantity of the toxin will make its way into the bloodstream, taking it to the liver. This turn of events can be especially dangerous, as in sufficient quantities oxalic acid can induce catastrophic liver failure, leading to serious illness and even death.
- All species of euphorbia have a milky plant sap of low toxicity that can irritate skin or open wounds and can cause nausea or vomiting if ingested.
Marty DeHart

Marty's lifelong passion for plants has led her to a long and varied career in horticulture: she's been a professional grower of gloxinias and African violets as well as perennials, a native plant propagator, a landscaper and landscape designer. She deeply enjoys learning constantly and sharing what she learns about plants, particularly information and techniques that can produce thriving plants and green-thumbed gardeners.