Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
You can associate a transmittance schedule to a shading surface. This is a fractional schedule where a value of 0.0 represents an opaque surface and 1.0 is transparent. You can change your value seasonally and based on time of day. Not sure if this is what you are looking for, but if you are trying to model the plants blocking some portion of the sun from the surface building then it may do what you want. Keep in mind that shading surfaces are not heat transfer surfaces and don't interact with the model in the same way.
