Strong base and/or solvents, indeed, easily will destroy some pH probes.
Endlessness is right about the solution turning black acting as a pH indicator in and of itself. It doesn't really take that much base to do the trick and personally I've never used a pH meter during a plant extraction.
To test a strongly colored solution using a pH strip you could take your drop of alkaline solution and dilute it in a small amount of distilled water, then use a drop of the diluted solution to drip onto the strip. This will reduce the amount of interference from the color of the solution.
“There is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
― Jacques Bergier, quoting Fulcanelli