The call for action for "Marigolds" starts when Lizabeth starts to realize that she needs to grow. This happens after she got "tired of the formlessness of her summer days".
The ordeal (climax)
The refusal of the call happens after lizabeth realizes that she needs to change but still goes with her friends and messes up the marigolds. Eventually, she'll realize that "those crazy flowers" Ms. Lottie always messed with will be the thing that helps her find her true self.
The road back (resolution)
Crossing the threshold happens after the kids in the group throw the rocks at Ms. Lottie and Lizabeth "lost [her] head completely". This qualifies as crossing over because even though she acts recklessly, she wouldn't have the confidence to act out if she was still childish so she's starting to mature, she just doesn't realize it just yet.
The ordeal happens after Lizabeth's parents get into an argument which makes her upset and she goes and messes up Ms. Lottie's garden. This counts as the climax because after all her built up stress and confusion, she lets it out by destroying the garden and from that point forward she realizes shes not a kid anymore.
The road back happens after Lizabeth's realizes the real beauty of the marigolds and begins reflect on her past. The meaning of the marigolds had such a big impact on her life that she eventually ended up planting a garden of marigolds on her own.
At the end of the day, there are many obstacles in your life but its up to you to decide when to let them help you grow.