Roses (バラ) are a common symbol in Sailor Moon and feature prominently in much Sailor Moon art.
Tuxedo Mask's trademark weapon in the anime was a red rose, which was strong enough to pierce any surface it was thrown into. He used it to distract enemies from attacking Sailor Moon or the other Senshi, giving him time to give a reassuring speech or the Senshi a chance to steady themselves and attack. In episode 101 he surrounded the Daimon Cenicienta with roses, which appeared to generate an energy field that injured his target.
It was not usually used to directly attack enemies, but he earned Zoisite's wrath when the rose cut his cheek once in battle. The roses were incorporated into his transformation, and he seemed to have a limitless supply of them.
The Moonlight Knight threw pure white equivalents to Tuxedo Mask's red roses.
During the time Prince Endymion was brainwashed by Queen Beryl, Tuxedo Mask's roses switched to black, representing the evil within him. In the episodes where the Sailor Senshi attempted to restore Tuxedo Mask, the roses (even after being thrown) would turn red and back to black again to show how much progress they were making.
Sailor Jupiter/Makoto Kino
In both Senshi and civilian forms, Makoto wore dusty red rose earrings. In the live-action series, her waist ornaments also featured a pink rose within a transparent sphere. In episode 171 of the anime, the sight of these earrings helped snap Usagi Tsukino out of her nightmare during Queen Nehellenia's revenge.
Kou Seiya, Kou Yaten, and Kou Taiki were frequently seen holding roses. Each rose was the color representative of the character's corresponding color in the Shinto concept of "san hikari" (三光; three lights).
In the live-action series, Dark Mercury's appearance was often marked by black rose petals.
In the live-action series, Mio's magical aspect was sometimes implied through the use of a flurry of black rose petals.