Torchwood is the plant in Plants vs. Zombies 2 that ignites peas passing through it, turning them into fire peas. Those flaming projectiles deal more damage than ordinary peas and can interact differently with ice-based effects.
Torchwood first appeared in the original Plants vs. Zombies, where it was positioned in front of Peashooters or other pea-firing plants to create flaming ammunition. Plants vs. Zombies 2 brought the same core ability into its time-traveling sequel, alongside new plant families, worlds, and combinations.
A common mix-up is Fire Peashooter, which produces flaming peas itself; it does not perform Torchwood’s support role. Snapdragon and Lava Guava also use fire, but attack zombies directly rather than converting passing peas. In PvZ2, Torchwood can also affect specialized pea plants, although some interactions vary by plant and version.