If "Roppongi" was named after the six trees, they must have stood out conspicuously in the area. They may have survived in a burnt-out area, or they may have been said to be inhabited by a god. Maybe they grew into an odd shape, bloomed a rare flower, or took root in a place with no rivals; maybe they glowed with LED lights wrapped around them, or maybe a good photo of them created a buzz. They must have attracted that much attention.
5-1-1 Roppongi, Minato-ku, Tokyo 106-0032 Japan