Yellow Floating Heart

Nymphoides peltata is native to a broad region spanning Europe, the Middle East, and temperate Asia, including parts of China, Japan, and the Indian subcontinent.

• Its natural range extends from Western Europe through Central Asia to East Asia
• It has been introduced to North America, where it is now considered an invasive species in many states and provinces
• In the United States, it was likely introduced in the late 19th century as an ornamental aquatic plant
• It has since spread aggressively through waterways in the northeastern and midwestern United States, as well as parts of Canada
• The genus Nymphoides comprises approximately 50 species worldwide, distributed across tropical and temperate regions on every continent except Antarctica

The Yellow Floating Heart is a rooted aquatic perennial with submerged rhizomes and floating foliage.

Rhizome & Roots:
• Horizontal, creeping rhizomes anchored in the muddy substrate of still or slow-moving waters
• Rhizomes are slender, branched, and capable of producing new shoots at nodes
• Fibrous roots extend downward from rhizomes into the sediment for nutrient absorption

Leaves:
• Floating, broadly ovate to nearly circular, 3–12 cm in diameter
• Deeply cordate (heart-shaped) base with smooth, entire margins
• Upper surface is glossy green; lower surface may be purplish and slightly pubescent
• Leaf stalks (petioles) are attached near the center of the leaf blade (peltate), giving the leaf a shield-like appearance
• Leaves are arranged alternately along the stem and float flat on the water surface

Flowers:
• Bright yellow, 2–4 cm in diameter, borne on short peduncles arising from leaf axils
• Five petals with distinctive fringed or lacerate margins, giving the flower a delicate, ruffled appearance
• Flowers open in the morning and close in the afternoon, typically blooming from June to September
• Both chasmogamous (open) and cleistogamous (closed, self-pollinating) flowers may be produced

Fruit & Seeds:
• Capsule fruit, ellipsoid, approximately 1.5–2.5 cm long
• Contains numerous small, flattened seeds with marginal wings or hairs that aid in water dispersal
• Seeds can remain viable in the sediment for extended periods

Nymphoides peltata thrives in still or slow-moving freshwater habitats.

Habitat:
• Ponds, lakes, ditches, canals, and slow-flowing rivers
• Prefers nutrient-rich (eutrophic) waters with muddy or silty substrates
• Typically found in shallow water, 0.3–3 meters deep
• Tolerates a range of water chemistry conditions but prefers slightly alkaline to neutral pH

Ecological Interactions:
• Provides shade and shelter for fish and aquatic invertebrates
• Floating leaves reduce light penetration, which can suppress submerged aquatic vegetation
• Flowers are pollinated by a variety of insects, including bees, flies, and butterflies
• Seeds and vegetative fragments are dispersed by water currents, waterfowl, and human activity

Invasive Behavior:
• In non-native regions, it can form dense mats that outcompete native aquatic plants
• Dense surface coverage reduces dissolved oxygen, alters water temperature, and disrupts aquatic ecosystems
• Listed as an invasive or noxious weed in several U.S. states and European countries
• Mechanical removal is difficult due to rapid regrowth from rhizome fragments

The Yellow Floating Heart is a popular ornamental plant for garden ponds and water features, valued for its attractive flowers and floating foliage.

Light:
• Prefers full sun to partial shade; flowers most prolifically with at least 6 hours of direct sunlight per day

Water:
• Still or very slow-moving water; avoid placement near fountains or strong water currents
• Optimal water depth: 30–90 cm, though it can tolerate depths up to 3 meters

Soil:
• Heavy, nutrient-rich clay or loam substrate
• Can be planted in aquatic planting baskets filled with aquatic compost and topped with gravel to prevent soil washout

Temperature:
• Hardy in USDA zones 5–11
• Tolerates cold winters; rhizomes survive freezing temperatures beneath the ice in temperate climates
• Growth resumes in spring when water temperatures reach approximately 15°C

Propagation:
• Division of rhizomes in spring is the most reliable method
• Seeds can be sown in shallow water or moist mud in spring
• Stem fragments with nodes can also root and establish new colonies

Containment:
• In regions where it is invasive, plant only in contained garden ponds with no connection to natural waterways
• Use planting baskets to limit rhizome spread
• Regularly remove excess growth to prevent overcrowding