Once wounded, plants use calcium signals to warn distant tissues of future attacks

Accept their death.

Put out chemicals that might lure a beneficial creature that might kill/eat the thing attacking the plant

Or increase levels of toxic chemicals, or move important nutrients away from that area.

It actually causes a (1^x) reaction and usually warns not just a few plants, but hundreds of them; in some grasses or tree growths, literally thousands... sometimes millions...
It can aso cause an (n^x) reaction. F U N.
Billions would be algae blooms but even though they get triggered... I don't think it's the same kind of response.... <_< bumchickawahwah.

then perish

Interesting question.