A lot of plant identification apps rely on image recognition to identify a plant, this is often unreliable, create a real-time, plant identification app that gets replies from existing communities.
There are a lot of existing websites like that help you identify plants tap into these existing communities to get type of plants and other advice on how to deal with that particular plant species. App can also help to identify plants, leaves, flowers, weeds and trees. It can later be expanded to indentify the particular insects on the plant as well.
The app can be monetized by selling ads to local nurseries, gardening services and tool suppliers.