Splendor In The Grass was inspired by a section of a poem called “Ode to Intimations of Immortality.”

What though the radiance which was once so bright
Be now for ever taken from my sight,
Though nothing can bring back the hour
Of splendor in the grass, of glory in the flower;
We will grieve not, rather find
Strength in what remains behind;
In the primal sympathy
Which having been must ever be;
In the soothing thoughts that spring
Out of human suffering;
In the faith that looks through death,
In years that bring the philosophic mind.

https://forallwehave.com/splendor-in-the-grass/

Now I'll have to sit and watch the movie online this weekend to see if there's other relevant hints he was trying to convey. Actors usually draw their inspirations and strengths from the artistry of others.