Thank you, everyone, for responding! I'm going to try to answer your questions.

Picked flowers or bought flowers?

Bought.

Why flowers?

Cut flowers are sort of a poetic metaphor for the therapeutic relationship--so circumscribed in their existence and transient by nature.

I don't care much about cultural connotations. I would hope my therapist doesn't either, or I'd be very disappointed in him.

But, really, WHY flowers?

Okay, okay, the real reason this became a thing (not that the above reason isn't real--it's just a post hoc justification) is that I have persistent morbid fantasies of visiting my therapist in the hospital and bringing him flowers. Sometimes the fantasy is going to his funeral and placing a flower in his coffin or tossing one into the grave.

Eventually I decided that if I want so badly to give him flowers, I should just do it now. Maybe if I just bought him some flowers I would stop having these fantasies. (Yeah, good luck with that, I know...)

Does my therapist like flowers?

I don't know if he likes flowers, but I've seen flowers in his office. I don't know if they're from another patient.

Why not get him something else?

I would love to make him a handmade item, but I'm bad at arts and crafts. I can bake delicious oatmeal raisin cookies, but cookies are so unhealthy.

If I grew tomatoes or other vegetables, I'd probably bring him some, but I don't.

Plants--well, I don't want to give him anything he has to maintain. A couple times a year, he goes out of town for weeks at a time, and I don't think a plant would survive that long without anyone to water it. Also, what if he hated the plant? Would he feel obligated to keep it in his office so as to not hurt my feelings? Cacti and succulents require less maintenance, but I don't really like them much.

I gave him a book once, but it wasn't so much a gift as extra work I wanted him to do.

What's the MESSAGE you're trying to send?

The nice, happy message: These flowers are pretty. I love you. Have some flowers.

The dark, morbid message: Let me give you some flowers to remind you of life's impermanence. I keep thinking you're going to die. These flowers are going to die too. In fact, they're more or less already dead.