Aponogeton natans

floating water hawthorn

At a Glance

FoliageDeciduous
Height1-2 inches (2.5-5 cm) above water surface
Width12-24 inches (30-60 cm)
Maturity1 years

Growing Zones

USDA Hardiness Zones

10
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancetender

Overview

Aponogeton natans is an aquatic perennial in the Aponogetonaceae family, growing from a tuberous rootstock anchored in the bottom substrate of still or slow-moving freshwater. Leaves are floating, oblong-elliptic, 2–6 inches (5–15 cm) long and 0.75–2 inches (2–5 cm) wide, bright green, with a smooth surface and parallel venation characteristic of the genus. Petioles extend from the submerged tuber to the water surface, adjusting in length to the water depth — typically 12–24 inches (30–60 cm). The inflorescence is a single-forked spike (bifid in some populations) that emerges 1–2 inches (2.5–5 cm) above the water surface, bearing small, white, fragrant flowers arranged in a dense cluster along one side of the spike. Fragrance is sweet, vanilla-like, most noticeable on warm days. The species is native to tropical and subtropical Asia, where it grows in ponds, slow rivers, rice paddies, and seasonal pools. Unlike the more commonly cultivated A. distachyos (water hawthorn) from South Africa, A. natans is less cold-hardy and requires water temperatures above 60°F (15°C) for active growth. Tubers go dormant when water temperature drops below 55°F (13°C). In the Pacific Northwest, it is grown as a container aquatic in lined ponds or indoor water gardens, overwintered indoors. Susceptible to aphids on emergent flower spikes and to crown rot if tubers are stored too wet during dormancy.

Native Range

Aponogeton natans is native to tropical and subtropical Asia, including India, Sri Lanka, Bangladesh, and parts of Southeast Asia. It occurs in still and slow-moving freshwater habitats — ponds, ditches, rice paddies, and seasonal pools — from lowlands to approximately 3,000 feet (900 m) elevation.

Suggested Uses

Grown in container water gardens, lined half-barrels, and indoor aquatic displays. Effective as a surface cover plant in small ponds, reducing algae by shading the water surface. In tropical and subtropical climates (USDA zones 10–12), planted permanently in ponds and slow streams. In the Pacific Northwest, treat as a tender aquatic — overwinter indoors.

How to Identify

Identified by the floating oblong-elliptic leaves with parallel venation and the single-forked spike of small white fragrant flowers emerging above the water surface. Distinguished from A. distachyos (water hawthorn) by the smaller leaves, less forked inflorescence, and the requirement for warmer water. Distinguished from Nymphaea (water lily) by the much smaller leaves, parallel (not palmate) venation, and the spike-type inflorescence.

Appearance

Size & Dimensions

Height1" - 2"
Width/Spread1' - 2'

Reaches mature size in approximately 1 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~14 weeks
J
F
M
A
M
J
J
A
S
O
N
D
Flowers appear intermittently from late spring through autumn when water temperatures exceed 65°F (18°C). Each spike emerges above the water surface and opens progressively over 5–10 days. In warm conditions, flowering is nearly continuous. Pollinated by insects visiting the emergent spikes. Small green fruit develop underwater after pollination.

Detailed Descriptions

Foliage Description

Bright green

Growing Conditions

Sun Requirements

Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)
357912
Soil Types
Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

tender

Time to Maturity

1 year from tuber

Care & Maintenance

Care Guide

Plant tubers 2–3 inches (5–8 cm) deep in a container of heavy loam (not peat-based compost) topped with gravel to prevent clouding, and submerge in still water 6–18 inches (15–45 cm) deep. Site in full sun to partial shade. Water temperature should remain above 60°F (15°C) for active growth. Feed with aquatic plant fertiliser tablets pushed into the substrate every 4–6 weeks during the growing season. In the Pacific Northwest, grow in a container pond or lined half-barrel that can be moved indoors or into a greenhouse before water temperature drops below 55°F (13°C) in autumn. During winter dormancy, store the container in a cool, frost-free location (40–50°F / 5–10°C) with the soil kept barely moist. Resume submersion in spring when water warms.

Pruning

Remove dead or yellowing floating leaves throughout the growing season. Cut spent flower spikes at the water surface. During autumn dormancy onset, remove all dead foliage. No other pruning is required.

Maintenance Level

moderate

Container Growing

✓ Suitable for container growing

Minimum container size: 5 gallons

⚠️ Toxicity Warning

Non-toxic