Dreamshade are a Neverland plant species. They first appear in the fifteenth episode of the second season. It grows in thorny bushfuls that ooze a liquid poison. In its natural form, the poison causes excruciating pain in the victim for a prolonged period, with a slow death. In a concentrated dose, dreamshade still affects the victim quickly, but causes the person to expire at a faster rate.
Liam purposely cuts himself with dreamshade to prove it is harmless, but when he becomes instantly ill, Hook tries to save him with Neverland's spring water. This binds Liam to stay in Neverland forever to remain alive, but after he leaves the island, he perishes to his dreamshade wound.
Hook procures dreamshade in a concentrated dose before leaving Neverland, which he later uses in an attempt to kill Mr. Gold.
The Lost Boys coat their arrows with dreamshade, with one of these piercing David during a battle.
Ambrosia are an Underworld plant species. They appear in the twentieth episode of the fifth season. Also known as the food of the Gods, the Ambrosia are so powerful that they absorb all the magic around them. One of their magical properties is to allow their eater to escape the Underworld. They grow at a far down point of the Underworld. To access to the field, one test must be completed. Unbeknownst to everyone, Hades cut the tree of the Ambrosia, so the plant disappeared.
Boro Grove's Spore Flowers are a Wonderland plant species. They appear in the sixth episode of the spin-off series. The spore flowers grow on trunks of Boro Grove trees, and they exude a purple-pinkish cloud of fog that gives off a fragrant perfume. Those that inhale the scent are plagued with almost instant amnesia and are drawn into a lively stupor of wanting to stay in the Boro Grove. If the person stays in this state after a short period of time, he or she will begin turning into a Boro Grove tree. The spore flowers affect humans, except for those who don't have their hearts.
Known Boro Grove's Spore Flowers:
Spore Flowers appear on all Boro Grove trees, trapping people in the forest.
When Cyrus is trapped in its vines, and while wrestling to untangle himself, the grapevine broadcasts his sounds of struggle miles away in the maze. Tweedledum hears Cyrus through the grapevine and prepares to report this to the Red Queen.
Pixie Flowers are a plant species of unknown origin. They first appear in the eight episode of the third season. Pixie dust flowers grow in "prisons of great evil" - the only reason why they grow in the first place. In Neverland, they grow in the highest of branches where they're closest to the stars, and only bloom at night under the starlight, which is how the pixie dust within them gets its magic. In Storybrooke, they have a different look and color, and grow on the ground. ("Think Lovely Thoughts", "Awake")
Known Pixie Flowers:
As Malcolm climbs a tree, he spots a flower on a branch and reaches into it, takes out a handful of pixie dust, and pours it over himself.