Symme-tree

Symme-tree is an instant-use plant. When planted, it affects the entire lawn, so it doesn't matter where you place it. It will flip plants from the bottom side of the lawn onto the top, and vice versa. This is helpful if you only have a few plants and want to fill the lawn.

Strategy
Fill the bottom three rows with the plants you want, then plant Symme-tree to instantly create fill the lawn with them.

Trivia

 * If there are graves or other obstacles in the way, it cannot spawn plants there.
 * Its ability is somewhat similar to the mini-game "Column Like You See 'Em", however it doesn't fill an entire column with plants.