Whether or not you’re an outdoorsy type of person, learning about the plants around you can prove extremely important. Whether you’re hiking, camping, having a picnic or playing in the yard with your kids, knowing which plants to stay away from can end up saving your life. Some of the most toxic plants are often the prettiest. Several plants on this list might surprise you!

Here are nine deadly plants you’d better stay away from:

1. Buttercups

Buttercups tend to grow in damp spots. There are several different species and many of them are poisonous. Buttercups contain caustic sap that can leave blisters on your skin if you come in contact with it. The poisonous sap also provokes coughing. If it gets into your eyes, it can cause temporary blindness.

2. Cowbane or Water Hemlock

Cowbane, also called Water Hemlock, grows in wet places like on riverbanks. It’s known as one of the most toxic plants on Earth. If you come in contact with it, symptoms can include nausea, seizures and even death.

3. Elder

The most common types of elder are red elder and black elder. While ripe black elderberries are safe to eat, every other part of the plant is toxic. Wash your hands immediately after touching an elder plant. Symptoms include headache, weakness, abdominal pains and occasionally seizures.

4. Oleander

Oleander is often used in landscaping thanks to its beautiful pink and white flowers. It’s also grown as a houseplant. While pretty, oleander contains cardiac glycosides that have the ability to alter your heart rate and cause nausea, headache, weakness and even death.

5. Hogweed

Hogweed is a giant plant that contains poisonous sap. The sap can cause severe skin and eye irritation, along with painful blistering, permanent scarring and even blindness. If you come into contact with giant hogweed, immediately wash the area with soap and water, and keep the area away from sunlight for 48 hours.

6. Rhubarb

Rhubarb is often used to make pies, salads and different sauces. What you might not know is that the leaves and the root of the rhubarb plant are toxic. They contain oxalic acid, which can cause burning in the throat and eyes, nausea, diarrhea and even kidney stones.

7. Castor Bean

When castor beans are used to make castor oil, the heat treatment destroys all the toxins. But castor beans on their own are deadly. They contain ricin and ricinine, compounds that destroy body tissues and can lead to death.

8. Aconite or Wolf’s Bane

Aconite, also called Wolf’s Bane, grows in Europe, Asia and North America. Despite its beautiful blue, purple and yellow flowers, Wolf’s Bane is extremely toxic. The pollen can cause cardiac arrhythmia, numbness and even death.

9. Spurge

Spurge grows in every environment. The plants are very diverse. Some look like cacti while others look like flowers. The sap from spurge plants can leave blisters, which can lead to swelling and fever.