So I did a little research on the web and came across the following:
"The pantheon of the Romans and the Greeks consisted largely of the same or similar gods, but there is a distinct difference between Mars and Ares. The not so well respected Ares was the god of actual combat and the destruction that followed, and he needed the guidance of the wise goddess Athena to not destroy everything. Mars on the other hand embodied both, and (as expressed in his romance with Venus) became the god of peace by means of military superiority. This explains why Mars could also be the god of husbandry, of shepherds and seers."
"According to Lewis and Short A Latin Dictionary, the name Mars is a contracted form of the older name Mavors... Mavors was The Turner Of The Battle, but it seems that Mavors or Mars rather turned the battle to peace than peace to battle."
Source:The amazing name Mars: meaning and etymology
So, given Mars is a being that represented prudence in military might and turned battle towards peace, I have equipped my Goddess Mars with both a sword and a rose. The sword to represent the might and will to fight for what is worth protecting, and the rose to represent the wisdom that all life is sacred and to seek peace in the midst of the tumult.
I also like the feathered headdress that is a bit reminiscent of a Valkyrie helm... a nod to the female warriors of Norse Mythology. As this Mars is a Goddess and not a God, I felt it appropriate.