What to do with flowers
Once you've climbed the cliffs at the back of the island, you'll discover your first flowers, unless you've visited mysterious islands, of course. Your first task with them is to make a crown, which should give you an idea of what to do with them following this goal. Flowers are a little less strict in their use, rather they exist primarily to improve the game and the environment. Sure, you can sell them, but they won't earn much for Nook's Cranny.
Planting flowers is more to beautify the region, but also to attract what flowers always attract in the real world: insects. Tired of roaming your island, net in hand, but no bugs to catch? Plant flowers in groups and you should start to see them appear. Often times, they will rest directly on the petals, so slowly go up and swing your net. And while they are part of this group, you can notice them developing and growing through flower selection.
If you plant two flowers of the same type such as roses, sunflowers or lilies side by side, they can breed and mix colors together. There must be space nearby for the new flower to appear, so if you want to start selecting flowers, place two side by side and watch the results.
Once you have these flowers, you can pick them by walking and pressing Y, or transplant them by digging them up and then planting them somewhere else. The picked flowers can also be used in various crafting recipes, such as the anterior wreath. Just watch for recipes to display in your DIY recipe app and work to develop what you need.
Fortunately, that explains what to do with the flowers in Animal Crossing: New Horizons.
