I think that depends, if we’re talking New52 Ivy than I don’t know much to be honest
But yes she isn’t as connected to the Green as Swamp Thing because he is an avatar of the Green itself, he is the Green incarnate
Her human side is what stops her making the full connection and that’s what leads to her conflicting nature
“It’s not long when I’m in one world before I miss the other. Not that I miss everything about the human world.”
I have a headcanon that when Ivy’s ‘human’ body dies, her connection with the Green becomes permanent and she becomes an all-knowing plant being or spirit, it makes sense, it happened to Alec
Also in the Infinite Crisis game, Atomic Poison Ivy is the result of a necular war causing all plant life to die around her and she goes into a coma, only to wake up as the least human plant-human ever
She refers to herself as ‘we’ and make no mistake there is no longer any human in her, apart from her human face, the rest of her is like a giant blossom vine hybrid, she walks on vines it’s so cool
But yes basically the Green took her completely and brought her back
I have yet to read the Infinite Crisis comics, the ones based off the game anyway but I’m hoping they include more on Atomic Ivy considering the game shut down recently