Identifying Petasites (Butterbur/Dinosaur Food): Invasive Shade Giant with Huge Leaves

Your Photo Nailed It: Petasites hybridus (or P. japonicus)

Thick rhizomes, 18″ leaves, celery-like stalks, early spring flowers before foliage, shade-loving, drought-tolerant = **Petasites**.

Warning: Highly Invasive

• Spreads aggressively by rhizomes.
• In Oregon (Zone 8), it will colonize wet areas rapidly.
• Difficult to eradicate once established.

Management

• Contain with deep barriers (24″+ HDPE).
• Or remove entirely: dig every rhizome fragment; monitor for years.
• Do not compost—rhizomes survive.

If you love the prehistoric look, pot it. In ground, it's a thug.