Pole Vaulting Zombies can vault over any plants in front of them. Therefore, planting Wall-nuts in front of them will be a waste. These zombies also move quicker than other zombies until they vault over a plant.
This level is easier in terms of building an offense because the player now has Potato Mines.
Use the same strategy you always had with Sunflowers and Peashooters to defeat the zombies. Try to plant a column of Wall-nuts closer to the center of the lawn.
When a Pole Vaulting Zombie comes into play, place a cheap plant like a Potato Mine ahead of the Wall-nut to force the zombie to lose his pole and spend time eating the Wall-nut.
If the Potato Mine is still recharging when the zombie appears, using the Sunflower may delay the zombie.
Closer to the end of the level, probably at the final wave of zombies, the defenses should be strong enough to defend all the zombies before they reach the Wall-nuts.
Never use an expensive plant to have the Pole Vaulting Zombie jump over, such as Peashooter.
We are back to normal in level 1-6. You’ve got the potatomine. It’s really cheap and useful. It can kill all zombies on it’s grid when exploding. You can plant 2 or 3 potatomines at the beginning of the level and wait for them to kill 3 zombies while planting sunflowers. Then plant some peashooters. There is a kind of zombie called pole vaulting zombies. They can use the pole to jump over a plant and they are fast before jumping. Don’t worry if you have 2 or more peashooters on this lane, if you don’t have that, just plant walnuts in front of them to force them to jump.