Torchwood

Torchwood is a plant which lights regular peas on fire when they go pass through his flame, adding extra damage and AoE attack. When planted during the Fog levels, it clears the fog around it for approximately one-and-a-quarter squares.

Although there is a flowering plant family known as Torchwood (Burseraceae [1]), which includes frankincense and myrrh, the name may also be a reference to the eponymous organization in the Doctor Who spin-off series.

Usage
Place Torchwoods in any lane in front of any plant that shoots peas to turn the peas into flaming projectiles that do double the normal damage. it also adds splash damage which deals a normal pea's damage to all nearby zombies. However, if a frozen pea passes through it, it will melt, becoming a normal pea that does normal damage.

Suburban Almanac Entry
Torchwood

Torchwoods turn peas that pass through them into fireballs that deal twice as much damage.

Special: doubles the damage of peas that pass through it. Fireballs deal damage to nearby zombies on impact.

Everybody likes and respects Torchwood. They like him for his integrity, for his steadfast friendship, for his ability to greatly maximize pea damage. But Torchwood has a secret: he can't read.

Cost: 175

Recharge: fast

Strategy
Torchwood should only be taken on levels where you plan to use peas to maximize the damage potential. You only need one in each lane, but it helps to plant one before placing a second pea-shooting plant in the same lane, as the fireball area damage will be more important than firing twice as fast. Keep Torchwoods behind your regular defenses such as Wall-nuts and Tall-nuts, but far enough to the right that you can place several pea-shooting plants behind it. Plan ahead if you intend to use Snow Peas, though, and put them to the right of any Torchwoods, as frozen peas melt when they go through a Torchwood. This is usually not worth it, however, as flaming peas will unfreeze zombies. It is better to use a Winter Melon in conjunction with the Torchwood instead, since the melons go over it and some of the zombies will stay frozen.

If you are using Split Peas to defend against zombies that can bypass your defenses, such as Digger Zombies or Imps (thrown by Gargantuars), you can place a Split Pea to the right of a Torchwood so its rear-firing peas will catch fire, doing extra damage. This works best if you have two or three Split Peas to the right of a Torchwood with other pea-shooting plants behind it.

The Torchwood should not be used in Fog levels for clearing fog because it only clears the fog a small area around it. Use a Plantern or Blover instead.

The Torchwood will not ignite Fumes, Spores, Kernels, Cabbages, Butter, Melons, Spikes, nor Stars so plan ahead when using them.

Trivia

 * The Torchwood, Plantern and Sea-shroom are the only three plants with visible roots.
 * The Torchwood, Plantern, and Blover are the only three plants that will let you see through fog.
 * The Zen Garden variety of Torchwood needs to be watered regardless of its flames, and they don't seem to be affected by the water.
 * The Torchwood, the Wall-nut, the Tall-nut, the Garlic and the Sunflower are the only plants that do not have an animation in I, Zombie levels.
 * The Torchwood, the Grave Buster and the Lily Pad are the only plants with yellow eyes.
 * If you look closesly or if you zoom in the image, the Torchwood has red pupils.
 * The flaming splash damage of a flaming pea can't affect a Newspaper Zombie, a Ladder Zombie, and a Screen Door Zombie while they still have their shield, as well as the Zomboni and the Catapult Zombie.
 * It is unknown why a flaming pea can't burn immidiately the Newspaper Zombie's newspaper, Instead, it just damages the newspaper.
 * The Torchwood does not seem affected when it melts the ice of the Snow Pea's projectile.
 * Torchwood is one of the twelve plants that appear in the seed selection screen after you get the Grave Buster on the online version, the others are: Ice-shroom, Lily Pad, Potato Mine, Threepeater, Tangle Kelp, Jalapeno, Spikeweed, Doom-shroom, Tall-nut, Cactus and Blover.