That’s a good point about dandelions, @Amethyst! I didn’t think about them that way, but now I do! 
Playing off the stubbornness of dandelions, part of their stubbornness is that they demonstrate the ability to rapidly evolve and adapt to their environment! As dandelions are cut back with each mowing of the grass, they adapt by not growing as tall as before so that they can try not to be cut down again. That’s pretty stinkin’ cool if you ask me! 
[Note: I remember hearing that dandelions grow back shorter when they’re cut down, but now that I’m trying to find a source for that information to share, I can’t find anything about it, so additional research on that is necessary before that claim is either confirmed or found to be untrue.]
Dandelions would also be a good choice for this spell (in my opinion) because the English name “dandelion” comes from the French for “lion’s tooth,” so if you choose to incorporate that lore into the intentions going into the spell bottle, you could incorporate that fierce lion energy with the “I’m going to adapt to anything that comes my way” energy into the bottle as well 
Of course, these are only my thoughts and perspectives, but correspondences are very personal and adaptable, so at the end of the day, the best items to use are those that you feel work best with your intentions, @TheMuslimWitch 