Here is a 100% walkthrough of Chapter 1: Thistles and Weeds including all the secret locations and the missable achievement
Gardener.
Secret / Collectible #1 - 2:00
Secret / Collectible #2 - 4:56
Secret / Collectible #3 - 6:24
Secret / Collectible #4 - 8:07
Secret / Collectible #5 - 9:51
Follow along the video to also unlock:
The Gardener achievement in Unravel worth 58 pointsTear down all the thistles in one go