Targeting us Because we have renters

Will try to make this short:
We owned and livind in the home for 4 years. Husbands job tranferred out of stet. Now rent to a Single Family. Filled out all the paperwork and submitted it to Mgnt Co for HOA.
Never had a violation

Since we have moved we have received two phone calls. one because they lost the paperwork. Which they subsequently found.

New Problem:
The AC unit needs to be covered with plants so you can not see it from the street according to our HOA Design review board criteria. Four years ago we ripped out the dead plant the builder had put in and never replaced them.
Of the 200 houses 38 currently have nothing infront of them. We planted the same plant that over 40 residents have covering their units. The HOA says its not good enough because the plant will not grow during the winter. None of the other homeowners have received violations for no plant.
What can we do about being targeted because we have renters? Is this against the law in any way?

How do you know that none of the other homeowners have received the same violation? If in fact they do not then I would correct your issue (ask the board for a plant suggestion) and once complete I would give them a polite list of others that have the same violation - or would bring it up at a baord meeting so it is out in the air that they are not being consistent

Yup, send the board a nicely written letter, saying something like: As we are sure that there are many other HO's with the same issue that will need to put in AC covering plants, can you provide to me (and them) any ideas of which plants are approved and being used? that way, I can acquire the same plants as my neighbors are using to terminate this citation, and the HOA will look pleasing to the eye because my plants will match those used by my neighbors.
I eagerly await any information you can share about the plants others are using to appease the board, so that I can comply as well.