Easy way of combining maps is by using layered texture. Wilt_Trans01 was made for the outline of the leaf geo.(so no need for extra detail modelling) Leaf_crack01 was a map painted for inside animatable transparency map
(Fig.06).
Fig. 06
Bottom Wilt_Trans01 is first file to be middle click drag and drop on the layered texture. Blend mode is multiply (Fig.07).
Fig.07
Taking a look at maps (Fig.08).
Fig.08
Wilted leaf shader:
Pretty self explanatory by looking at the Fig.09 image. yellow ($) concept is already explained on the above, so they are using same method and concept for spec, bump, transparency animation. Blue ($) is also same concept as yellow ($) except additional colour files I have connected to each ramp circles. (More detail below).
Fig.09
Closer look at blue($):
Fancy red star Anim_Ramp01 is the animation ramo that drives transparency, colour and bump animation. This way we do not have to animate everything all separately (Fig 10).
Rot_Color01 map is a colour map that is a key for wilted look of the leaf. Yellow halo and brown dried spot look is achieved with animating this map. After you connect Anim_Ramp01 to Rot_color01 like we discussed earlier, now you mid click drag and drop all three CL_01,02,03 into each ramp circles for the colours.
Fig.10
Reference Images:
Find reoccurring patterns throughout the images rather than trying to copy what looks like from these images (Fig.11).