Flowers can say "congratulations" or "I'm sorry." They can be a romantic gesture or just make a space more pleasant.
But whether it's a nice bouquet of roses or a pot of tulips to plant in the garden, why exactly do people like flowers so much? According to author Loretta Bruening, much of that enjoyment comes courtesy of chemicals in the brain tied to evolutionary history.
On a basic level, flowers' bright colors appeal to our evolutionary love of variety, explained Bruening, author of "Habits of a Happy Brain." Just spotting that pop of color releases dopamine, which signals to the brain that it's about to get a reward and leads to excitement.
"Imagine your hungry ancestors see some color in the far distance and they're hungry and tired," she said. "That says 'Wow, maybe that's an oasis and we're going to get water and fruit' and that gives you the energy to keep going."
Modern humans no longer search the landscape for food as a matter of survival and "don’t consciously link flowers with food. But the blossoming of a flower triggers the sense that something special is coming because it triggers dopamine," Bruening wrote in a blog post for Psychology Today.
Another of the happy brain chemicals that flowers can spur is oxytocin, the thing that causes animals to seek social support.
"It gives us the good feeling of social trust, so this whole thing about giving flowers, receiving flowers and communicating with flowers, it's social trust that we're looking for," Bruening said. "That eases our survival fears and gives us a sense of being safe."
Bruening added that flowers are a symbol of that because it's a gesture that someone is trying to build an alliance and that's what our brain is looking for.