Semiosis by Sue Burke

Only mutual communication can forge an alliance with the planet’s sentient species and prove that mammals are more than tools. Forced to land on a planet they aren’t prepared for, human colonists rely on their limited resources to survive. The planet provides a lush but inexplicable landscape–trees offer edible, addictive fruit one day and poison the next, while the ruins of an alien race are found entwined in the roots of a strange plant. Conflicts between generations arise as they struggle to understand one another and grapple with an unknowable alien intellect.