Water lettuce Plant Care

Water lettuce (Augusta rivalis) belongs to the Rubiaceae family within the Augusta genus. Water lettuce is native to Mexico, Central America and Colombia. Water lettuce is also known as Nile cabbage, shellflower.

Water lettuce displays a compact, bushy shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Water lettuce produces small, fragrant white flowers in clusters.

Leaf size: approximately 4 inches.

Water a young or newly planted Water lettuce every 7–10 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Water lettuce thrives in bright indirect light. Avoid placing Water lettuce in direct, harsh sunlight for extended periods, as this can scorch the foliage.

Augusta rivalis tolerates temperatures of 65–75°F. Water lettuce prefers humidity levels of 50–70%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Rich, well-draining soil with added organic matter like compost or peat moss. Good drainage is essential for Water lettuce to prevent waterlogging, which leads to root rot and fungal issues.

Feed Water lettuce every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

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

Choose a spot with bright indirect light and rich, well-draining soil with added organic matter like compost or peat moss. Avoid low spots where water collects after rain.

Water lettuce is suited to USDA Zone 10b – 12b.

Plant container-grown or balled-and-burlapped shrubs in spring or early autumn, setting the root flare at soil level, and water well after planting.

Water lettuce can spread to about 2 ft (0.6 m) and reach about 3 ft (1 m) tall. Space plants about 2 ft (0.6 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the plant spacing calculator.

Prune Water lettuce while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the shrub in one year.

Water lettuce is frost-tender (hardy to USDA zone 10). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Water lettuce can be propagated through softwood cuttings, air layering, division.

See all plants toxic to cats and plants toxic to dogs.

Water lettuce is susceptible to aphids, spider mites, scale insects. 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.

Water lettuce grows outdoors in USDA Zone 10b – 12b. It survives winters down to planting zone 10b. Water lettuce is native to Mexico, Central America and Colombia. In cooler regions, grow Water lettuce as a houseplant or bring it indoors before the first frost.