The Tree of Hearts is a magical tree that connects to all Heart Flowers. If a Heart Flower wilts completely, it will weaken the Tree of Heart. It is unknown what will happen if the Tree of Hearts dies, but at the present it is now under grave danger, as all its flowers have fallen. According to Cure Moonlight, the reason the Tree of Hearts still is alive is because, as long as Pretty Cure exists, it will never die. The only way to restore the Tree now, is to collect Heart Seeds into the Heart Pot until it is all filled up. As Pretty Cure collects Heart Seeds one at a time, the Tree is slowly getting better, to the point that it is capable of giving birth to a new baby fairy, Potpourri.
It is never stated where the Tree of Hearts is, but it is seemingly in a flying island in the skies. It also appears above the Pretty Cure Palace.