Spitting Flowers are game mechanics introduced in Angry Birds 2. They have the ability to trap and then shoot objects out of them.
Spitting Flowers act as "cannons" that shoot out anything that falls into their open petals, regardless of their size. Objects that can be captured and shot back include blocks, pigs, or even the birds themselves. However, spitting flowers cannot hold more than one object at a time or capture rockets. There is roughly a one second interval in which the flowers reopen themselves, ready to recieve more falling debris.
One strategy involving the use of birds is to aim them into the flowers in order to shoot them at a different angle or a distance that cannot be reached by the slingshot. Once swallowed and re-shot by the flower, the player can still activate bird abilities if they haven't become corpses, allowing for more options on how to complete the level. Bomb in particular benefits from this strategy well, as it allows him to reach areas that are inaccessible from the slingshot without blowing his fuse.