Spatterdock / Cow Lily

Nuphar advena
Native Floating
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Quick ID Summary
What It Looks Like
Heart-shaped leaves that often float but can also emerge up to 2 feet above the water surface. Yellow flowers 1 to 2 inches in diameter, blooming in July and August.
Where It Grows
Growth typically occurs in 1 to 2 feet of water. A network of rhizomes connects to long stems.
How It Spreads
Rhizome and seed distribution.
Status
Native. An excellent source of cover and habitat for fish, and food for aquatic life and for animals outside the pond. Also called yellow pond lily, cow lily, and bullhead lily.
Spatterdock leaves standing above the water surface
Spatterdock / Cow Lily — Nuphar advena, formerly treated as Nuphar lutea subsp. advena

Identification

Spatterdock is an emergent aquatic plant with heart shaped leaves. Those leaves often float, but they can also emerge from the water - standing up to 2 feet above the surface. That standing habit is distinctive; true water lilies lie flat.

The flowers are yellow and 1 to 2 inches in diameter, blooming in July and August. Below the surface, a network of rhizomes connects to long stems. Growth typically occurs in 1 to 2 feet of water.

Telling Spatterdock from Water Lilies

Spatterdock is confused with water lilies routinely. The flower is the fastest check: spatterdock's yellow flowers are much smaller than lilies, at 1 to 2 inches in diameter. The leaf habit helps too - spatterdock leaves frequently stand above the water rather than resting on it.

Why It Matters

Spatterdock is worth thinking about carefully before treating. It is an excellent source of cover and habitat for fish, and it provides food for aquatic life as well as for animals outside the pond.

Management, rather than removal, is usually the right frame for a plant doing this much work in a waterbody.

Control Approach

Early season, from the bottom. Navigate is granular and the granules sink to the bottom, which suits a rhizome-based plant. It is used for early season control.

Later, from the top. Clearcast is sprayed on mature vegetation at the water surface, with results noticed in 7 to 10 days. It can be mixed with Pondzilla treatment enhancer.

Which one you reach for is mostly a question of timing: whether you are ahead of the growth or dealing with mature pads and flowers.

Recommended Treatment Products

These are the products Natural Waterscapes recommends for spatterdock / cow lily, with the role each one plays. Read the label and confirm the product suits your waterbody before applying.

Early Season, Granular
Navigate (2,4-D)
Granules sink to the bottom. Used for early season control of spatterdock.
View Product
Mature Vegetation
Clearcast (Imazamox)
Sprayed on mature vegetation at the water surface. Results are noticed in 7 to 10 days.
View Product
Treatment Enhancer
Pondzilla Pro
Can be mixed with Clearcast as a treatment enhancer.
View Product

Common Questions

How do I tell spatterdock from a water lily?

Spatterdock's yellow flowers are much smaller than water lily flowers, at 1 to 2 inches in diameter. Spatterdock leaves are heart shaped and often stand above the water surface rather than floating flat.

When does spatterdock flower?

The yellow flowers bloom in July and August.

How deep does spatterdock grow?

Growth typically occurs in 1 to 2 feet of water.

Is spatterdock good for a pond?

It is an excellent source of cover and habitat for fish, and provides food for aquatic life and for animals outside the pond.

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Need help with spatterdock / cow lily?

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