Use chili plant to clear the ice, after than, put a spikeweed with enhancement at the right side so that any zomboni which will attempt to come in will be destroyed immediately.
The most effective way of dealing with the red suit zombie is to plant three spikeweeds adjacent to each other, they cannot succeeded in walking through it.
Need to plant as many sunflower as possible to get energy fast in order to use chili plant.
Start the game by planting Sunflower and spikeweed first.
Also refer to Plant vs Zombies : Survival: Endless (Hard) Tips