How does Jerry Spinelli use imagery in Love, Stargirl?

Imagery:

"I've become pretty good at telling weeds from not-weeds. But every once in a while I have my doubts. I come across an especially difficult root. I pull and it doesn't come out. I pull again. It resists. I dig my gloved fingers into the soil and grab it with both hands and pull yet again. It begins to come out, but I can see it's going to take several more hard pulls. And that's when the doubts begin. I begin to wonder: Have I made a mistake."

"Your answer has been a new sunrise for me, my own personal Solstice, the dawn of a season that I will, as Betty Lou would say, inhabit one day at a time. I will sail into the future on mystery's wings and I will not look back."