Mentha aquatica
watermint
Europe, northwest Africa, southwest Asia
Overview
Mentha aquatica is an aromatic, rhizomatous perennial of wet ground, 15-90 cm (6-35 in) tall, with square, often red-tinged stems and opposite, oval, toothed leaves 2-6 cm (0.8-2.4 in) long that smell strongly of peppermint when bruised. From midsummer it carries dense, rounded heads of small lilac to pink-purple flowers at the stem tips, with one or two extra whorls below. It spreads aggressively by creeping rhizomes and surface runners that root at the nodes, forming wide colonies in shallow water and saturated soil. The vigorous habit lets it cover pond margins quickly but makes it difficult to confine in mixed plantings. Top growth dies back in autumn and regrows from the rootstock in spring. The flowers draw heavy insect traffic, and the foliage carries the menthol scent common to mints. It grows in standing water up to about 15 cm (6 in) deep as well as in wet soil, and weakens only where the ground dries out.
Native Range
Mentha aquatica is native to Europe, northwest Africa, and southwest Asia, and it is widely naturalised elsewhere. It grows in marshes, fens, ditches, wet meadows, and the margins of ponds, lakes, and slow streams. It is not native to North America, where it has naturalised in scattered wetland sites.Suggested Uses
Planted at pond and stream margins, in bog gardens, and in wildlife ponds where it shelters small aquatic life. Used as a late nectar source for bees, hoverflies, and butterflies. Its rampant spread makes it suited to contained margins rather than open mixed plantings.How to Identify
Appearance
Size & Dimensions
Height6" - 2'11"
Width/Spread2' - 4'
Reaches mature size in approximately 2 years
Bloom Information
Detailed Descriptions
Foliage Description
Mid-green, often red-tingedGrowing Conditions
Sun Requirements
Requires 4-12 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
Care & Maintenance
Care Guide
Grow Mentha aquatica in wet soil or shallow standing water up to about 15 cm (6 in) deep, in full sun to partial shade. It establishes at pond and stream margins and in bog gardens, and tolerates a wide pH range. The plant is hardy and needs no winter protection across temperate zones. Because it spreads aggressively by rhizomes and runners, grow it in a planting basket or contained margin where the colonising habit is unwanted. Cut back top growth in late autumn once it dies down. No feeding is needed in reasonable wet soil.Pruning
No formal pruning is needed. Cut back faded stems in late autumn or early winter after they collapse. Lift and divide congested colonies in spring to control spread and refresh growth.Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons