Humans have always been affected by the plants in our environment. As our ancestors moved out of the trees and down onto the ground, the plants we ate changed. Anthropologists can look at the teeth of the ancestors and determine what those people were eating by the wear patterns. And when our ancestors settled down with agriculture the plants we used changed again.
We started to pick crops and develop better strains. Higher yields. Better flavor. Sometimes lucky mutations helped speed things up. The grass teosinte had a mutation that changed its seed head into a tiny “ear” and human selection increased the size of the ears until we had corn. Which happened in South America. Corn then spread across North and South America with most of the native cultures. After European contact, corn spread to Europe and Asia too.
Actually many plants associated with European cuisine are actually plants from the Americas. Most of us think of tomato based sauces when we think of Italian food, but tomatoes came from America first. And while we think of potatoes as associated with Irish, English, or possibly French (French fries) cuisines, they were actually originally domesticated in Peru.
We've continued to change the way we live, requiring far fewer of us to spend the time growing all the plants that become our food. But even then most of us still have plants in our environments. We have our ornamental lawns and flowers. Where we still use human selection to improve the various species and varieties we plant. With plant breeders finding genes that special plants can be created, with properties we find desirable. Though we still can have fashions in the plants we like to have around, it seems unlikely that anything like the tulip mania that happened in Holland in the 1600s will ever be seen again. (Though it seems we haven't learned the lessons about speculative bubbles in economics that we could have.)
And plants have even helped us learn about genetics for all living things. Gregor Mendel developed the original understanding of genetics from cross breeding different types of pea plants. By tracking parent and offspring types he was able to watch the effects of different genes on the development of the peas.
Other branches of science have discovered other things that plants do for us. It was only relatively recently (mid to late 1700s) that we learned of photosynthesis and the production of oxygen by plants. And while various chemicals in the soil are important, most of a plant's mass comes from water and the air (carbon dioxide) around us.
Given the importance of plants in our lives, I can't think of too many books, stories or movies where plants play a truly significant role. There are some, like Medicine Man (1992) where cures for diseases are being looked for from plants in the jungles of South America. Speaking of drugs, I guess the movies of Cheech and Chong might be movies where plants play a big role, but that's not really where I was wanting to go with this.
Little Shop of Horrors is one example where a plant is the threat that must be faced. The original movie came out in 1960, and the sheer insanity of it gave the movie a cult following. (According to Wikipedia, the movie was shot in 2 days, on a leftover set, with a budget of $30,000.) The cult following later helped generate the stage musical in 1982. Which Tehachapi Community Theatre will be presenting in September. This Faustian tale takes Seymour from loser to high roller due to his “discovery” of a unique species of plant. But I don't intend to spoil the story. You're going to need to see it to believe it.
And as a full disclosure I'm helping out behind the scenes on the show. though if you look closely you might spot me staggering about on the stage.