And, if you don't want to do this the old-fashioned way using actual B&W IR film, one can either:
a) Convert one of your old beater DSLRs for this purpose by removing the IR-reject filter in front of the sensor, and put an IR-pass filter over the lens. I've never done this myself, but there is a quite a subculture of photographers going this route, and they produce beautiful images, and a lot of discussion of this approach on the web.
b) Fake it in PS. Below, I used the more or less the method suggested by AgentM, except that I first selected the green areas, then brightened, desaturated, and adjusted their contrast (while still in RGB color mode), then did a final conversion to B&W.
Original:
Conventional B&W conversion:
TJM's B&W IR simulation:
Adobe even has a preset for their B&W adjustment layer called "IR". Personally, I never use it as I think the results are too harsh, e.g.,
HTH,
Tom