How much sun does Rocky Mountain Cowlily need?

Rocky Mountain Cowlily grows best in part shade conditions.

When does Rocky Mountain Cowlily bloom?

Rocky Mountain Cowlily blooms in June, July, and August.

Where is Rocky Mountain Cowlily native?

Rocky Mountain Cowlily (Nuphar polysepala) is native to AZ, CA, CO, ID and 7 more states, per the World Checklist of Vascular Plants (Kew).

What pollinators does Rocky Mountain Cowlily attract?

Rocky Mountain Cowlily draws beetles and flies.

Is Rocky Mountain Cowlily HOA-friendly?

Rocky Mountain Cowlily takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Rocky Mountain Cowlily

Name: Pollinator Patch
Author: Pollinator Patch

Nuphar polysepala

Last reviewed: August 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

Before you buy

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Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 432 programs across 44 states, each with a link to the provider and the date we last checked it.

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Browse plants for this ecoregion

Coast Range Puget Lowland Marine West Coast Forest Northwestern Forested Mountains Sierra Nevada Central California Foothills and Coastal Mountains North American Deserts Central Basin and Range Southern Rockies

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.

Common questions

How much sun does Rocky Mountain Cowlily need?: Rocky Mountain Cowlily grows best in part shade conditions.
When does Rocky Mountain Cowlily bloom?: Rocky Mountain Cowlily blooms in June, July, and August.
Where is Rocky Mountain Cowlily native?: Rocky Mountain Cowlily (Nuphar polysepala) is native to AZ, CA, CO, ID and 7 more states, per the World Checklist of Vascular Plants (Kew).
What pollinators does Rocky Mountain Cowlily attract?: Rocky Mountain Cowlily draws beetles and flies.
Is Rocky Mountain Cowlily HOA-friendly?: Rocky Mountain Cowlily takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

Ready to grow Rocky Mountain Cowlily? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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