Deeply rooted plants can resist drought by "spending" water rather than saving it

Besides the "normal" soil moisture reserve, which is the rooted zone replenished by rainfall and irrigation, plants sometimes tap into an underground reservoir.  In monitoring wells throughout urbanized Broward and Miami-Dade counties, the mean depth of the Biscayne aquifer is 1.45 m and the average standard deviation across months is 0.06 m (Busey, 1996).  Thus even in the driest months, deeply rooted plants such as woody ornamentals and some turfgrasses (e.g., bahiagrass and this FX-10 St. Augustinegrass) tap into the ground water and need little or no supplemental irrigation.