Nicole Zempel shows viewers staghorn sumac, a plant that is eye-catching in the fall. Nicole Zempel shows viewers how to harvest sumac berries in late summer and into fall by clipping the cone tops.

What’s that red in the woods? Sumac, most likely. “It’s a harbinger,” said Julie Janoski, Plant Clinic Manager at The Morton Arboretum. “When you see those first scarlet sumac leaves, you know autumn ...