I've always been fascinated by the idea of sentient plant species. Plants have so much variety, so many adaptations and so much potential for interest. Their experience of the world would be fundamentally different than that of any animal because their methods of living are so different. From feeding through photosynthesis to reproduction through the release of pollen, fruiting, or even budding.
Their point of view would be inherently different and that must have an effect on the way they’d view other forms of life. They need sunlight and water, and they take nutrients from the soil, while all forms of animal life--even herbivores--kill something in order to survive, and imagine that from a plant’s perspective. Of course, perhaps you’re building a species of sentient plant that evolved from carnivorous plants! :-D
Animal life can also have reactions to plants. We can be allergic and they can be poisonous, but plants can also be curatives or drugs. And if that’s the case it would certainly present conflicts, from the idea of sentient plants being the cure of a plague, to an entire black market economy based on the sale of euphoric sentient plant sap. Do the plant people have to die in order to create the poison/drug/curative? Perhaps it’s the basis of their own economy, or the economy of their criminal element.
What would a society of plant people be like? How do they determine who gets the sunniest spots, or the clearest water, or the soil with the most nutrients. Perhaps those go to the leaders, or the oldest, or the strongest, or even the youngest so that they can grow more quickly. The leaders may warrant more sun, while the youngest (saplings?) warrant more water. Are there some plants which are more or less respected? Which get first use of certain resources?
And what about the criminal elements of such a society? What counts as a crime for plant people? They’re just as capable of injuring one another as we are, just as capable of theft, slander, murder. You have to determine how their society punishes such acts, how it views such acts.
Is there hunger or poverty in such a society? There are limited resources. There are only so many spots of ground and plants need hours of sunlight. Perhaps they’ve become nomadic, similar to the way that farmer’s rotate their crops in order to replenish the nutrients in the soil. They may have to be very conscious of what goes into the ground, as well as what comes out of it.
If there’s more than a single species of sentient plant, how do they view one another? Some species might be invasive, taking up soil and sun and water without care for what others need and spreading their own seeds at the cost of other species. Their view of non-sentient plants would be interesting as well. When you need daily sunlight in order to survive, a forest might be a terrifying place, too dark for you to eat in. Plants might even be looked at as we look at other animal species. Some could be pets, but some are probably predators or weeds.
Are your plant people mobile? Perhaps they can move about, but have to put down roots in order to feed and thus must spend parts of the day rooted to a spot. Or perhaps they’re mobile for parts of their lifespan, but rooted at other times. The young might be rooted until they’re grown, or perhaps they grow more sedentary as they age.
Let’s not forget reproduction! How they accomplish reproduction will certainly color their views on any number of other topics, from gender and sexuality to family, religion, philosophy, children, marriage and politics. Some plants are hermaphroditic, producing both male and female blooms. Others have only one gender. Some produce from cuttings and others through different types of pollination. How does a sentient plant view life when reproduction means cutting off a part of themselves to plant in the ground? What sorts of philosophies spring from requiring insects to choose the person you reproduce with?
To us, forests and deserts may be challenging, but how are these geographies viewed by sentient plants? Creating such a species means looking at grasslands and rocky coasts and stretches of sand in entirely different ways. A forest has layers, and each plant that lives within it is adapted to their own space. From the tallest plants which get the most sunlight—and thus block a good deal of it—to the small underbrush which has learned to live with only dappled light. For them, too much sun is just as dangerous as too little. Some plants are resistant to drought and some are not. Some can stand freezing temperatures and some can’t, and all of them deal with these things in different ways. Some of those ways may be similar to our own concepts—if you can’t take the heat, build some shade, or if the weather outside’s too cold, build a greenhouse—but some will no doubt be quite different.
Life cycles also provide a vast array of possibilities. Some plants don’t live long at all, while others can live for centuries. Some lay dormant waiting for just the right conditions in order to spring to life. Some release pollen when stressed, some bear fruit.
I think there’s a lot of untapped potential when it comes to such species. We see a lot of the same types of things over and over, but there so many different kinds of plants and so many different ways for them to evolve, all depending on where they came from. There’s plenty of ways to introduce conflict and story, and so many possibilities for characters and cultures. Basically? I’d love to see more sentient plants!