The Bower Boys from my YA novella, THE UNMOVING SKY, publishes with Leap Books, is about two brothers, 17 and 15, lost in the woods, who are found by a stranger with destructive plans. The "Bower Boys Survival Tips" are some of what they might find in the woods and could consume for energy (food), and, or medicine.
They'd find the red berries in the late autumn, and the petals during June, which can be eaten too.
I'm updating this post from a couple years ago, and you'll have plenty of time for preparations. I bet you can find a few dried red berry still on the vine.