That was it. She was gone. Locked forever in a parallel world. He had no way to reach her, yet still he tried. He burned up a sun to say one last good-bye. Other companions came and went, but they never replaced her.
Donna, she was there, right after Rose left. He would have liked for her to be his companion, but it still wouldn't be the same without Rose. While Donna was gone, The Doctor found roses. Roses of the purest color out there, all different shapes, sizes, colors, and patterns. They were exotic all except one. There was one plain, red, rose, that was among the group. It was there to remind the Doctor of how simple a human Rose was, but how much she meant to his heart. He strung them together in a string, used science and love to make them forever alive. Mind you, it was a long string of roses. The Doctor hung them across the support beams of the TARDIS. He draped them everywhere. Soon, the TARDIS filled with the sweat scent of roses, but it did nothing to ease his pain.
Soon, Martha came along. She didn't question the roses at first, just thought it odd. That is, until she realized she wasn't the first to be here, and she wasn't exactly the one that held The Doctor's heart either. Every time she asked what the roses were for, he would just turn away and fall into silence. Martha came and went, just like the other companions. The Ponds, they did the same thing. Always asking, but never getting an answer.
The Doctor went through regenerations, but still never forgot the lovely Rose that forever held his heart. The roses around the TARDIS never died, always stayed the same. Filling up the air with a sweat smell. Then, it happened. The Doctor couldn't live forever. He couldn't just keep regenerating. He finally died, saving the world one last time. As he took his last breathes, his companion in the TARDIS, he thought of Rose. All the lovely times they shared, and what might've been. His companion, who was now preparing the TARDIS to leave, noticed the roses. They were dying. Wilting in front of her eyes. The color seemed to be sucked away from them, all accept one. One stayed, alive and blood red. It lived on. Even as the companion went to The Doctor, even after the companion lay beside the Doctor, the rose lived on. The Doctor thought of Rose before he died. His last breathe came out in a whisper, a whisper of hope and love. A whisper of sorrow and pain. A whisper, for her. The TARDIS got blasted into space, doomed to forever float without meaning, without a destination. The red rose inside stayed alive, the lone rose of TARDIS. It seemed to live on with the memory of the lovely Rose Tyler, who had no way of knowing that The Doctor was gone.
The rose survived with the TARDIS, forever a memory of what should've been.