A few weeks ago lost balls were not an issue in the naturalized areas. Now that the grass has reached middle school height, you need more clarity.
It is a local rule. It is not a "red" or "lateral" hazard.
UNMARKED PENALTY AREAS (Natural Areas)
All unmarked areas of native grass that border some holes, are considered penalty areas. These areas are not marked, however if a player’s ball comes to rest in these areas, players are entitled to relief, under penalty of one stroke. When the penalty area is not defined by lines, the natural boundary of the native area will define the margin of the penalty area. Under penalty of one stroke, the player may take two club-lengths from the spot where the ball last crossed the margin of the penalty area.
Adding Clarity
"ball last crossed the margin of the penalty area"
Your drop point is where your ball crossed into the penalty area
Your drop point is NOT parallel to where your ball came to rest
"the player may take two club-lengths from the spot where the ball last crossed"
This is NOT stance plus two club lengths
It is ONLY two club lengths from spot of entry
Time
How long do you get to search for your lost egg? USGA rule does kick in here.
"Under Rule 18.2, the time for a ball search (before the ball becomes lost) has been reduced from 5 minutes to 3 minutes."