Threepeater

The Threepeater shoots Peas in not only its own lane but the adjacent lanes above and below. These are a handy middle-to-late game weapon, although it is best not to place them in the top or bottom rows, as then they can only fire two peas rather than their usual three. However, it is a good idea to place them there after placing them in the other rows.

Suburban Almanac Entry
Threepeater

Threepeaters shoot peas in three lanes.

Damage: normal (for each pea)

Range: three lanes

Threepeater likes reading, backgammon and long periods of immobility in the park. Threepeater enjoys going to shows, particularly modern jazz. "I'm just looking for that special someone," he says. Threepeater's favorite number is 5.

Cost: 325

Recharge: fast

Strategy
Since it fires down all three lanes whenever it sees anything in any lane, it can potentially hit zombies just as they enter the right side of the screen - well before other plants have noticed them. It's especially useful on pool levels, and in conjunction with the Torchwood. It is also notable that two Threepeaters in the second and fifth columns can cover all six lanes.

Trivia

 * If there is a Threepeater on the top or bottom row, the top or bottom head (respectively) does not have its firing animation play, as it cannot fire outside the screen.
 * The Threepeater is only available in the full version of the game.
 * The Threepeater's three heads bounce at different speeds. The bottom head bounces the slowest, while the middle head has an average speed, and the top head bounces the fastest.
 * Each head also has a different amount of leaves on the back: the bottom one has one leaf, the middle two, and the top one three.
 * If a Torchwood is planted directly above or below the Threepeater, the Threepeater will shoot fireballs directly out of its top or bottom head (respectively) without the peas even touching the Torchwood.
 * Likewise, if a Torchwood is planted in the row above or below a Threepeater but one column ahead of it, the Threepeater's peas will turn into fireballs despite not having fully moved into the row and not having gone through the Torchwood.
 * The Threepeater is the only plant with three heads.