Water Fringe (Nymphoides peltata) — identification, habitat & look-alikes

Water fringe, better known in the US as yellow floating heart, is a European and Asian water plant with round floating leaves and bright yellow flowers whose five petals have fringed edges. Sold as a pond ornamental in the US, it has escaped into lakes and rivers in many states, where it can form dense mats that crowd out native plants.

Appearance

Growth form: A perennial rooted in the bottom mud, with long, branching runners up to about 6½ ft (2 m) that lie just under the surface.
Leaves: Round to heart-shaped floating leaves, about 1¼–4¾ in (3–12 cm) across, green to yellow-green with slightly wavy edges and often purple underneath.
Flowers: Two to five bright yellow flowers per node, about 1–1½ in (2–4 cm) across, held just above the water. Each flower lasts only one day.
Flowering time: May through October in the US, depending on water temperature.
Fruit: A beaked capsule about 1 in (2.5 cm) long, holding flat, shiny seeds edged with stiff hairs.

Look-alikes

Spatterdock (yellow pond-lilies)Nuphar

Check the petals: yellow floating heart has five flat yellow petals with fringed edges, and its round-to-heart-shaped leaves are often purplish underneath. Spatterdock flowers lack the fringe.

Why they get mixed upBoth float leaves on the water and have yellow flowers; native spatterdock is sometimes mistaken for it.

Little floatingheartNymphoides cordata

Little floatingheart has white flowers and smaller heart-shaped leaves, about 1¼–2¾ in (3–7 cm) long. Yellow flowers mean yellow floating heart.

Why they get mixed upA native relative in the same genus with similar floating heart-shaped leaves that are also purple underneath, found in the East from Maryland northward and in the Southeast.

Where it lives

Typical habitats: Ponds
Lakes
Reservoirs
Slow rivers
Range: Native to most of Europe and temperate Asia. The earliest US record is from Massachusetts in 1882, and it has since been reported from more than 35 states plus Washington, D.C., though not all of those populations may still survive.
Preferred conditions: Freshwater only, in still or slow-moving water about 1½–13 ft (0.5–4 m) deep.
Flowering: Flowers May–Oct
Flowers May–Oct

Life cycle

Seed dispersal: Seeds float on the water and can cling to waterfowl by their edge hairs.

Growing it

Care: Popular as a water-garden ornamental, but it grows aggressively, and escaped plants have started many of the wild populations.
Propagation: Spreads by runners and , and broken pieces can drift downstream and root as new plants.

Conservation

IUCN Red List: LCLeast ConcernLow risk of extinction
Status: Washington lists it as a Class B (since 2001) and on its quarantine list. In parts of its native Europe it has become rare and is listed as threatened in several countries.