The Fire Berry plant is made of a strong main plant with vines that tangle around it and protect its fruit. The Fire Berries start off gray and turn a burnt orange color when ripe! As the berries ripen the plant begins to lose it's leaves for winter, making it very colorful!
It has two layers of flesh, an outer bitter light orange flesh and a sweet yellow flesh in the middle. Most Pokemon and people prefer the berries to be cooked as that brings out their sweetness.
When eaten, Fire moves will be 2x as strong for a short time.