Photoshop

 I used the images that I took in visual language of my green objects, the brief required that we stuck to our given colour, I thought I would keep my idea simple and remove all colour present in my images apart from green.

 I made a duplicate layer and made the background image black and white so I could remove areas of colour from the top layer to leave the black and white image.

 I changed the colour balance slightly to +20 towards the green end of the spectrum to enhance the colour.

Also very importantly I changed the colour mode to CMYK as these images are for print not for screen.