Rocky Mountain Cowlily
Nuphar polysepala
Last reviewed: June 2026
Light
part shade
Water
high
Size
12"–36" H × 24"–48" W
Bloom
Jun, Jul, Aug
Native to
AZ, CA, CO, ID and 7 more states
Pollinators
beetles, flies
Browse plants for this ecoregion
Rocky Mountain cowlily is an aquatic perennial native to mountain lakes and ponds. It produces large, round floating leaves and bright yellow cup-shaped flowers during summer months. This plant requires standing water or consistently saturated soil to thrive.
In an HOA neighborhood
Rocky Mountain Cowlily takes more care to keep looking intentional in a front yard. Maintenance level: high. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Requires pond or water feature
- Very specialized growing conditions
- May appear unkempt without proper water management
Wildlife value
The flowers attract beetles and flies for pollination. Seeds and rhizomes provide food for waterfowl and other wetland wildlife.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Does Rocky Mountain Cowlily fit your yard? Open it in Pollinator Patch to check it against your sun, soil, and HOA-conscious filters.