You are lucky to have several types of special plants that you can use to fight against these dead walking creatures.
Among these plants is the Snow Pea where it has the capability to shoot a pea that has an effect to slow down the movement of its target.
This will allow you to inflict more damages before they can even reach half the distance on your house.
Planting a Snow Pea requires energy from the sun which can be acquired naturally or generated by a Sun-Flower plant.
The cost of energy required is worth 175 which are more expensive than the ordinary type of Pea shooting plant.
Moreover, Snow Pea shooter plant can be acquired by completing the easy challenge of the level 1-7.
You will find out that using a Snow Pea as one of your offensive types of plant on the field will provide a great help in eliminating the zombies.
It is extremely useful especially on a multiple huge wave attack where a group of zombies will suddenly appear.
Huge waves or the final wave is signified by a zombie carrying a red flag.
Higher challenges of the game will become more difficult to overcome where relying on your plant's capabilities will no longer work.
You have to devise a good strategy by choosing the right type of plant and assigning them on a perfect location on the battle field.