Plants

Plants are found all across a Terraria world, and may grow from certain block types given various conditions. Most can be harvested for use, and may additionally drop seeds for replanting, such as Jungle grass and seeds. Different biomes generally have distinct plant life.

Herbs
Herbs are used at a Placed Bottle or an Alchemy Table to craft potions. They can be found all across the world, or in, and can be harvested with almost any weapon or tool. Each herb will bloom when certain requirements are met. Herbs harvested while blooming will drop 1-3 seeds of their kind in addition.

Mushrooms
Regular Mushrooms can be turned into Vile Mushrooms and vice versa using Purification Powder, Unholy Water, or Holy Water, respectively.

Vines
(Needs update since 1.4 there are 5 vine types with flowery vines added) Vines are plants that grow downward from blocks. Given there is enough empty space, they can reach a length of up to ten tiles. Although they block light, they do not impede movement and can easily be destroyed with nearly any weapon or tool. Destroying a tile of a vine destroys all tiles of the vine below it and destroying the topmost tile or mining the block it hangs from will destroy the entire vine.

There are four different types of vines: Regular vines (grow from Grass and Leaf Blocks), Jungle vines (grow from Jungle grass blocks), Hallowed vines (grow from Hallowed grass blocks), and Crimson vines (grow from Crimson grass blocks). There is no Corruption variant of vines. Vines can only grow above the surface (with the exception of Jungle vines which can grow at any elevation) and only from blocks that are not sloped on their underside.

Vines can be painted. New vines growing from painted blocks will take on the color of that block and vine tiles spawned by naturally extending vines will take on the color of the existing tip of the vine. In Hardmode, Crimson and Hallowed vines qualify as spreading tiles in regard to biome spread. The allows the collection of  from vines.

Vines will never drop the Vine object; this is an uncommon Man Eater drop.

Cactus


Cactus grows naturally on Sand Blocks in the Desert biome, and persists even if the Desert becomes infected with Corruption, Crimson, or Hallow. They can be cut down with any axe and can be used to make cacti-themed weapons, armor, furniture, or just be placed and used as a building material. Occasionally, a Pink Prickly Pear will grow on top of a cactus. In and before, mining the Sand Block underneath a cactus will cause the entire plant to drop, but since  this is no longer possible.

Bamboo


Bamboo grows naturally on Jungle grass that is submerged under water 2-5 blocks deep. It grows in straight columns at a very slow rate. Bamboo can be cut down with a pickaxe and can be used to make furniture.

Thorny bushes
Thorny bushes grow naturally in the Corruption, Crimson and Underground Jungle, and will damage the player on contact. There are currently three types of thorny bushes: Brown bushes from the Underground Jungle deal 25 damage; purple and red bushes from the Corruption and Crimson, respectively, deal 10 damage each. Thorny bushes are destroyed after contact with a weapon or tool. Invisible projectiles (Medusa Head, Life Drain etc.) don't destroy thorny bushes. Thorny bushes can grow six tiles in all directions. All NPCs and enemies are immune to them. They cannot be obtained as an item. The purple and red variants spread the Corruption/Crimson; the brown variant, however, does not spread Jungle grass. The growth of thorny bushes is blocked by solid objects and various other scenery.

Sunflowers
Sunflowers are surface plants that prevent the spread of the Corruption and Crimson on the blocks they are planted, and provide the buff to players within a 50-tile radius, mildly increasing movement speed and reducing monster spawn rate.

Life Fruit
Life Fruits are consumables that permanently increase the player's maximum health by 5, up to a total of 500 (20 used). They are found in the Underground Jungle during Hardmode / after defeating at least one mechanical boss. Life Fruits become more common once more mechanical bosses have been defeated. Life fruits will glow under the effect of spelunker potions.

Dye Plants
Dye Plants can be crafted into Dyes at a Dye Vat. They can be encountered in various biomes, and show on the map.

Strange Plants
Strange Plants are uncommon quest items that can be traded with the Dye Trader, who rewards the player with one of 33 animated dyes, all but two of which are quest-exclusive.

Plantera's Bulb
Plantera's Bulb is a pink plant in the Underground Jungle that will begin to appear after all 3 mechanical bosses and the Wall of Flesh have been defeated in a particular world. It will summon Plantera when destroyed. Though it cannot be broken by weapons or projectiles, caution should still be taken if these conditions are met to prevent any unwanted boss fights. One bulb will spawn about every six minutes (roughly half of an in-game day.)

Pumpkin
Pumpkins grow naturally during Halloween and can be planted with Pumpkin Seeds sold by the Dryad. It can be placed as well as crafted into armor, furniture, walls, and Pumpkin Moon Medallions. There is also a chance to get the Magical Pumpkin Seed.

History
Pflanzen Plantes Növények 식물 Plantas Трава 植物