The Soldier Pea is an all-around plant that uses a rocket launcher for a primary weapon and a shotgun for its secondary weapon. It also carries a shovel for melee attacks. To switch to secondary, right click the soldier pea. It will also give you information about its current health, ammo left, and more useful info.
This is unlocked right when you get it, and is used as a primary weapon for the Soldier Pea. Its explosion has the blast radius of about a square, so any zombies near the explosion will be damaged. The one who gets hit directly with it gets blown back. The rocket does 10 NDS to the zombie hit, and 6 NDS to all of the zombies in the radius. However, it can only hold 4 rockets at a time and the soldier pea has to load in each rocket one at a time. Also, the Soldier Pea can also be damaged by his own rocket via splash damage.
The shotgun is the secondary weapon for the Soldier Pea, and will be used when the zombie invasion is too close for the rocket launcher to be helpful. People think that this is a better weapon then the rocket launcher, as it has both more ammo carried and a larger clip to store shotgun shells. However, its near useless at far-range and it has to empty its old shotgun shells before entering in new ones.
The folding shovel can only be brought out when another zombie is biting it or hitting it with another melee weapon. This means that its otherwise unavailable as a real weapon. However, it has no ammunition other then itself, and while it only hits a single zombie at a time, it can quickly get rid of a mob of zombies