Spearleaf Water Plantain Plant Care

Spearleaf Water Plantain (Alisma lanceolatum) belongs to the Alismataceae family within the Alisma genus. Spearleaf Water Plantain is also known as Lanceolate Water Plantain.

Spearleaf Water Plantain displays a clump-forming aquatic plant growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Spearleaf Water Plantain produces small white or pink flowers on tall stalks.

Leaf size: approximately 6 inches.

Water a young or newly planted Spearleaf Water Plantain every 3–5 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.

Spearleaf Water Plantain thrives in full sun to part shade.

Alisma lanceolatum tolerates temperatures of 60–80°F. Spearleaf Water Plantain prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Rich, loamy soil with good moisture retention. Good drainage is essential for Spearleaf Water Plantain to prevent waterlogging, which leads to root rot and fungal issues.

Feed Spearleaf Water Plantain 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 full sun to part shade and rich, loamy soil with good moisture retention. Avoid low spots where water collects after rain.

Spearleaf Water Plantain is suited to USDA Zone 13a.

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.

Spearleaf Water Plantain can spread to about 2 ft (0.5 m) and reach about 2 ft (1 m) tall. Space plants about 2 ft (0.5 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 Spearleaf Water Plantain 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.

Spearleaf Water Plantain is frost-tender (hardy to USDA zone 13). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Spearleaf Water Plantain can be propagated through division, seeds. Similar propagation techniques also apply to channelled water plantain plant care, which shares the same genus.

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

Spearleaf Water Plantain is susceptible to aphids, leaf miners, snails. 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.

Spearleaf Water Plantain grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. In cooler regions, grow Spearleaf Water Plantain as a houseplant or bring it indoors before the first frost.