Last Stand - Slowly spiking them

Plants
Spikeweed AKA "W"

Snow Pea AKA "S"

Tall nut AKA "T"

Lilypad AKA

Upgrades
Spikerock AKA "R"

Cattail AKA "C"

Setup
S _ _TRRWWW

S_ _ TRRWWW

C C (T)

C C (T)

S _ _ TRRWWW

S _ _ TRRWWW