By Francie Murphy and Chris McDonald.
As gardeners in San Diego move to replace their thirsty lawns and water-loving plants, they may unknowingly turn to harmful replacements. Some of the most common shrubs, succulents and even a few vegetables can be harmful if they are not handled carefully. Rest assured, there are steps you can take to protect you and your loved ones. The San Diego office of the University of California Cooperative Extension recently partnered with the County of San Diego to create a website (https://ucanr.edu/sites/PlantSafely/) where the public can identify many popular drought-tolerant plants that are also toxic or can cause injury.
Oftentimes drought-tolerant plants, which are naturally found in arid regions, have protections that detract a potential herbivore from eating them to help the plant preserve precious water. These protections might be physical, like spines, or chemical, such as toxic sap. These plants can be safely placed in your garden by taking a few protective measures such as planting them where they cannot be easily touched, and when working with the plants wearing gloves and long sleeves, using eye protection, and supervising children and animals playing nearby.
One of the most popular and toxic plants showing up in landscapes throughout San Diego County is Sticks on Fire, also known as Fire Sticks or Pencil Cactus; the botanical name is Euphorbia tirucalli. Its dramatic red and green stems have led to legions of fans who use the harmless looking succulent as a drought-tolerant staple. Many public spaces and even playgrounds are ringed with this attractive plant that can land you or your pet in the emergency room.
Trimming this plant increases your chance of being injured -- stems break off easily and exude a toxic, milky sap that can get into your eyes or on your skin. People who have gotten sap in their eyes have needed emergency medical care to rinse out the burning sap and prevent further injury. San Diego County Master Gardeners recently worked with the University of California Cooperative Extension to create a short video showing the right and wrong ways to work with Fire Sticks. The video, posted on the UCCE Planting Safely homepage, can be viewed here.
It’s a good idea to learn the common and scientific names of the plants in your garden just in case a family member or visitor is accidentally injured. Being able to identify the offending plant will help first responders render treatment more quickly and efficiently.
Wondering if you have any toxic plants in your yard? Here are some of the most common:
Tropical Milkweed: The only food of Monarch butterfly caterpillars, this beautiful flowering plant has a milky sap that is toxic to skin and eyes. All parts of the plant are poisonous if ingested. Protection is needed when planting or pruning.
Nightshade Family: This popular family of plants includes chiles, tomatoes, potatoes, eggplants, jalapenos and bell peppers. It’s enough to fill a good-sized raised bed, but don’t eat the leaves or stems. Some nightshades are used as decorative plants in the garden too. Some species also have little spines and irritating hairs so supervise pets and children playing nearby.
Sago Palm: The tips of its leaves are surprisingly sharp, and this stately plant is very toxic to humans and animals. The fruits and seeds produced by the female plant are also poisonous.
Agave: A ubiquitous plant on slopes, many leaves contain toxic sap and different varieties have very sharp spines. It’s also important to know how large the mature plant will become. Do not plant it close to walkways.
Prickly Pear: The large spines can often be avoided; it’s the tiny spines or glochids you don’t want to brush up against. Wear two pairs of gloves when working with this plant or heavy-duty cactus gloves. Some varieties can also grow up to 30 feet tall.
Bougainvillea: No doubt it’s painful when poked by this vine’s large thorns. A coating on the surface of the thorns also can cause skin irritation. This quickly spreading plant often needs pruning, so remember to wear gauntlet gloves that cover your arms and a long-sleeve shirt made from heavy fabric, along with long pants. A face shield is also recommended because long, wispy branches can accidently whip your face.
Bird of Paradise: Admired for its colorful flowers, every part of this plant contains a substance which, if ingested, causes gastrointestinal irritation, nausea and vomiting. Plant away from walkways and areas that attract children and pets.
There’s much more information on the Planting Safely website, including a list of over 70 common landscape plants that can pose a threat if not handled with care or planted in a safe location. The current season in San Diego is the perfect time to plant new things in the garden. Before heading to the nursery, however, consult this list. And then share it with family and friends.
Francie Murphy has been a UCCE Master Gardener in San Diego since 2014. She loves her roses, especially the “antique” varieties.
Chris McDonald is a UCCE Inland and Desert Natural Resources Advisor and County Co-Director San Bernardino.