Plants

Plants are found all across Terraria, including several types of grass, mushrooms, cacti, herbs, thorny bushes, sunflowers, and more. Most of them can be harvested to collect itself or its seeds. Each Biome has its own types of plants.

Cacti
Cacti can be found in the Desert biome on sand. It can be chopped down to receive Cactus. It deals 10 damage to the player when touched. Similarly to Thorny Bushes, all NPCs and monsters are immune to them. When growing, cacti will override any existing blocks that are in the way, destroying them.

Thorny Bushes
Thorny Bushes are plants that grow naturally on Corruption and Underground Jungle, like grass. Unlike grass though, Thorny Bushes will damage the player on contact. Currently, there are two types of thorny bushes: red bushes that grow in the Underground Jungle which deal 25 damage and purple bushes that grow in the Corruption that deal 10 damage. Thorny Bushes grow in all directions (not just upwards), and may spread. All NPCs and monsters are immune to them. They cannot be obtained as an item.

Sunflowers
Sunflowers are found on grass on the surface. They are not only there for decoration, but they also stop corruption from spreading. You can pick them up by destroying the grass on the block under them with a pickaxe.