River mint Plant Care

River mint (Mentha fluvialis) belongs to the Lamiaceae family within the Mentha genus. River mint is native to Europe excluding Britain and Ireland, western and central Asia, and northern and southern Africa. River mint is also known as Water mint.

River mint displays a spreading, mat-forming herb growth habit, reaching up to 1 ft tall with a spread of approximately 1 ft. River mint produces small, lilac to white flowers in terminal spikes.

Leaf size: approximately 2 inches.

Mentha fluvialis requires watering every 3–7 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.

River mint thrives in full sun to partial shade.

Mentha fluvialis grows best at temperatures of 60–80°F. River mint prefers humidity levels of 50–70%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Well-draining, fertile soil with a neutral pH. Good drainage is essential for River mint to prevent waterlogging, which leads to root rot and fungal issues.

Feed River mint every 2 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.

Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.

The PlantoScan app can remind you when to water and when to fertilize each plant.

Divide and repot every 2-3 years. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.

River mint can be propagated through division, stem cuttings, seeds. Similar propagation techniques also apply to spearmint plant care, which shares the same genus.

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River mint is susceptible to aphids, spider mites, mint rust. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

River mint grows outdoors in USDA Zone 6a – 9b. It survives winters down to planting zone 6a. River mint is native to Europe excluding Britain and Ireland, western and central Asia, and northern and southern Africa.