Summer in California means spending plenty of time outdoors, from beach days and backyard barbecues to sunset strolls and scenic hikes.

In 2024, California was ranked the second-best state for hiking in United States by GB The Green Brand for its stunning coastlines, dense forests and rugged mountain ranges.

Before you hit the trails or relax in your garden, it’s important to know which plants could be harmful to you or your pets.

From flowering blooms to long grasses, here are some native plants and invasive species in California that can pose a risk:

How to avoid poison oak in California

Justin Valliere, an assistant cooperative extension specialist at UC Davis who specializes in plant sciences, said there are dangerous invasive and native plant species people should look out for while outdoors in California.

“The biggest threat to folks out hiking is poison oak,” Valliere told The Modesto Bee. “It is a native plant species and does really well along trails.

He said rising temperatures, along with increased carbon dioxide levels, are contributing to the spread and increased toxicity of poison oak in California.

“This means more people may encounter poison oak and experience more severe reactions,” Valliere said.

According to the National Park Service, the main effect of poison oak on humans is an allergic reaction to urushiol, which is the oily substance found in all parts of the plant except its pollen.

This allergic reaction typically creates an itchy rash that can develop into blisters, cause discomfort and, in severe cases, might require medical attention.

“Contact with contaminated objects like clothing or pets that have touched the plant can also lead to exposure and allergic reactions,” Valliere said. “It’s best to use cold water immediately after exposure.”

Look out for these harmful native plants

Another native plant to avoid is eriodictyon parryi — or better known as poodle-dog bush, Valliere said.

It’s most commonly found in Southern California and tends to thrive in areas recovering from wildfires.

According to the National Institutes of Health, poodle-dog bush is a “growing cause of contact dermatitis in California.”

If you come into contact with poodle dog bush, the health agency said, immediately wash the affected area with soap and water to remove plant oils. Avoid touching the area and potentially spreading the oils to other parts of your body.

Antihistamines are not effective, the health agency said. Instead, use topical treatments such as calamine lotion, cold compresses and, in severe cases, corticosteroids to provide relief from the rash and itching.

What toxic plants should my pet avoid?

According to UC Davis, your pet should avoid daffodil, which can cause vomiting, diarrhea, stomach pain, irregular heartbeat and breathing problems.

“If you suspect your pet has ingested any of the following plants, call your veterinarian immediately,” UC Davis said. “Do not wait to see if symptoms appear because in some cases of poisoning, by the time symptoms appear, it’s too late to save the animal.”