Plants that can cause a severe allergic reaction are poison oak, poison ivy, poison sumac, certain trees such as juniper, birch and even giant hogweed.
Other plants that can trigger allergic reactions are sunflowers, chrysanthemums, stinging nettle and ragweed.
Plants such as poison ivy, poison oak and poison sumac contain urushiol which is an oil that triggers an allergic reaction in many people and causes an itchy, red rash with a blister.
Some people are more severely allergic to poison ivy, poison oak and poison sumac than others and may require an injection and hospital visit.
Stinging nettle is a plant that has hairs which inject an irritant when touched and causes a stinging and burning sensation and potentially hives.
The giant hogweed has sap that can cause severe burns and blistering upon contact, especially when the skin that is exposed to the sap is exposed to sunlight.
Plants that cause pollen allergies are ragweed, birch, oak, juniper and mulberry.
Ragweed is a common weed allergen, especially in the late summer and fall.
Birch, oak and juniper are trees that produce pollen and can trigger seasonal allergies in many people.
Mulberry is a tree that is known for it's high pollen production and can also be a significant allergen.
Some people have allergic reactions to sunflowers, Peruvian lily and Chrysanthemums.
The bulbs and saps of daffodils, tulips and hyacinths can also cause skin reactions in some people.
And even fig trees and rubber plants can cause allergic reactions in people that have latex allergies and it most commonly causes contact dermatitis.