The story you're about to read actually happened to my parents and not me.
My parents were on a weekend getaway and booked a room in one of the hotels here. The furnishing was pretty standard; a queen sized bed, floor to ceiling windows, office desk, etc. But what caught their attention was a vase with a pleasant arrangement of flowers, which consisted mostly of roses. So just before they left the room, my mom decided to pluck a rose and place it in her hair.
She spent the whole time outside the room with the rose in her hair. By evening time, they came back to the room for dinner and retired for the night. After lying in bed for a short while, my mom started feeling a presence beside her (other than my dad) and she swore she even felt the physical force pressing down on the bed. Before she could think about turning around to face this presence, she found herself being pressed down on the bed and then she started suffocating. She didn't feel any hands or recognizable "limbs"...just a malevolent force pressing down on her. After maybe a couple of minutes, the force stopped and she woke up (yea, it was a nightmare) in cold sweat. She then turned to wake my dad up and asked if he saw what happened. My dad simply told her it was just a bad dream and told her to get some sleep.
The next day however, after checking out, my dad told my mom what really happened. Apparently, my dad had a dream during the little episode my mom had, and in his dream, he saw a rose on the floor. When he looked at it, he could see that the rose was slowly contracting and expanding its petals, as if it was breathing. After the dream ended, he woke up; walked to the rose my mom left on one of the side tables and placed it outside of the room. After doing that, he went back to bed and was abruptly awakened by my mom who just finished her nightmare.
I won't mention the name of the hotel but it was decades ago and it has undergone several renovations by now.
You might be interested in the book "The Secret Life of Plants." They detail an experiment where, with sensors attached, it was found than an orange cringes before you cut it with a knife. Also how trees shiver when someone who has chopped down neighboring trees comes near them.
However-plants obviously don't inhale and exhale like lungs move, and the unnatural image of the breathing cut rose is extra frightening to me.
Is there any way the flowers arrangement had been moved from another placement or event, or left behind unintentionally by another, first recipient?