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Plant guide · Floating plants

Watershield (Brasenia schreberi)

A native floating plant with small, oval, waxy leaves attached at the center, a jelly-like coating underneath and small purple flowers.

Small oval watershield leaves floating on dark water, some turning red and yellow.
Watershield leaves on the water surface. Photo: Ryan Hodnett, CC BY-SA 4.0 (source)

What it looks like

  • Oval (elliptical), waxy floating leaves, smaller than lily pads.
  • The leaf stem attaches at the center of the leaf's underside.
  • Jelly-like (gelatinous) coating on the stems and the purplish leaf undersides.
  • Small purple flowers.

Easily confused with

  • White water lily: much larger round leaves with a slit.
  • Yellow floating heart (invasive): small heart-shaped leaves and yellow flowers.

Good and bad for your pond

  • A native plant that provides cover.
  • Can spread over shallow areas.

Native or invasive?

Native

Native. Native (USDA PLANTS; Penn State lists it among native floating plants).

USDA PLANTS: BRSC (lower 48 states: native)

Do grass carp eat it?

Grass carp usually leave it alone

Grass carp usually don't control watershield. Grass carp prefer submerged plants like pondweeds, elodea and coontail; they rarely control algae mats or lilies.

Checked Oct 4, 2026 · Source: Using Grass Carp to Control Aquatic Plants (updated May 19, 2025) This may be outdated

Control options

Prevention first

Penn State Extension's advice for every nuisance plant and algae problem starts with nutrients: overgrowth is a symptom of excess phosphorus and nitrogen from sources such as barnyards, crop fields, septic systems, lawns and golf courses. Cutting fertilizer near the pond, maintaining septic systems, diverting nutrient-rich runoff and keeping a vegetated buffer strip are the long-term fixes; without them, control becomes a yearly chore.

Checked Oct 4, 2026 · Source: Filamentous Algae (updated May 19, 2025) and the companion Penn State plant fact sheets This may be outdated

Remove it by hand or machine

Pull or cut small areas around docks and launches (PFBC).

Biological options

None effective.

Chemical options (permit first)

Any herbicide or algaecide in a pond needs a joint DEP/PFBC Chapter 91 permit first, at any amount. Only products registered with the U.S. Environmental Protection Agency and with the Pennsylvania Department of Agriculture, and labeled specifically for aquatic use, can be listed on the Chapter 91 permit application.

Checked Oct 4, 2026 · Sources: Water Quality Permitting for Pesticide Applications in Pennsylvania: FAQ (rev. Feb 21, 2025), FAQ #2, #3, #8, #10, #11, #28, #29; Permit Requirement for Use of an Aquatic Herbicide in Ponds (updated Sep 8, 2025) This may be outdated

Follow the product label; the label is the law. A Chapter 91 permit is required before any herbicide or algaecide goes in a pond (see fact). Consider a licensed applicator.

Sources

Checked Oct 4, 2026