You can enter the violet flowers to heal while shrunk. When Alice approaches them, their uncannily hand-like stamens start make grasping moves. Upon entering the flower, the petals close around her and health steadily recovers. Case in point, what the hell can a flower's stamens do to a teenage girl to restore her mental health???
Actually, there is more to that. The less health Alice has, the closer she is to Hysteria. Now, up to XIX century there was a trusted and tested method to cure female hysteria - 'pelvic massage' until 'hysterical paroxism'. Ahem.
So, the violets represent Alice's sexual frustration?
Most unlikely because side conversations in the London parts about Alice include how she doesn't like being touched.
By that point, Alice is about eleven different types of crazy. Not so unreasonable to assume that she could be both sexually frustrated and not like being touched. Also, A Date with Rosie Palms...
Okay gross, true but gross.
It could be that the closing of the bud, not involving the stamen, gives Alice a meditation sphere. Something like a Cooldown Hug. Also the flower's color might produce blue lighting which has proven calming effects. There is also the fact that the flower is of tropic origins: elongated stamen is common in wetter regions.
Maybe there's a chemical explanation, and the movements are merely symbolical (like how Alice obviously doesn't pick up teeth just by standing near them, even though that's how the game mechanics work). We never see how she interacts with the plants once she's inside them, and they do disappear when she's done using them.
Had anyone noticed the dark ring around the screen when London Alice obviously hallucinates? They might prove helpful of separating real and imaginary.