Alisma lanceolatum
A perennial aquatic herb with lance-shaped leaves and pinkish-purple flowers.
Alisma lanceolatum, called lanceleaf water plantain or narrow-leaved water plantain, is an aquatic perennial in the water plantain family. It grows across Europe, North Africa, and temperate Asia, and has become naturalized in Australia, New Zealand, and parts of western North America—Oregon, California, and British Columbia. In some areas it is listed as a noxious weed.
This plant is a common weed in rice fields, notably in New South Wales and California. In England and Wales it occurs occasionally in local spots; in Ireland it is rare, and in Scotland it is very rare. It lives in mud and fresh water.
The herb grows from a caudex in water or mud, reaching about 0.7 meters tall and spreading 0.25 meters. Its lance-shaped leaves, on long petioles, are 12 to 20 centimeters long and 4 centimeters wide; submerged leaves are smaller and have less prominent veins. The mostly erect inflorescence can be up to half a meter tall. From June to August, it produces many small, pinkish-purple flowers with three petals, which open in the morning. The fruit is a cluster of about 20 tiny achenes, each 2 to 3 millimeters long. The reddish-brown seeds are roughly 1.5 millimeters long.
For cultivation, it grows best in water 15 to 30 centimeters deep, in full sun, and suits USDA hardiness zones 5 through 8.
A similar species, *Alisma plantago-aquatica*, has acute leaf tips that do not taper into a stalk, wider leaves, and flowers that typically open in the afternoon.
Quick Facts
- Genus
- Alisma
- Species
- lanceolatum
Facts from the source article.
Lore & Background
Alisma lanceolatum is a perennial herb that grows from a caudex in water or mud, typically reaching a height of about 0.7 meters and a spread of 0.25 meters. It produces lance-shaped leaves 12 to 20 centimeters long and 4 centimeters wide on long petioles; leaves that remain submerged are smaller and less prominently veined. The inflorescence is mostly erect and up to half a meter tall, bearing a wide array of small pinkish-purple three-petalled flowers that open in the morning from June until August. The fruit is a tiny achene up to 2 or 3 millimeters long, clustered into an aggregate fruit of about 20 units, with reddish-brown seeds about 1.5 millimeters long.
Reader's Guide
Alisma lanceolatum is significant as a weed of rice fields in many areas, including New South Wales and California, and is considered a noxious weed in some places. Its distribution is widespread across Europe, North Africa, and temperate Asia, and it has naturalized in Australia, New Zealand, Oregon, California, and British Columbia. In England and Wales it is occasionally locally found, in Ireland it is rare, and in Scotland it is very rare. It is found in mud and fresh waters. For cultivation, it grows best in water 15-30 centimeters deep in full sun and is suitable for USDA hardiness zones 5–8. The species is distinguished from the similar Alisma plantago-aquatica by its acute leaf tips that taper to a stalk, and its flowers that open in the morning rather than the afternoon.
Did You Know?
- Alisma lanceolatum is a weed of rice fields in New South Wales and California.
- Its flowers are pinkish-purple with three petals and open in the morning from June until August.
- The fruit is an aggregate of about 20 tiny achenes, each up to 2 or 3 millimeters long.
Frequently Asked Questions
What is Alisma lanceolatum?
It is a perennial aquatic herb commonly called lanceleaf water plantain, belonging to the water plantain family. It is recognized by its long, narrow leaves and small pinkish-purple blooms.
Where is Alisma lanceolatum native to?
This species is originally found across Europe, North Africa, and temperate regions of Asia. It has since established itself in Australia, New Zealand, and parts of western North America including Oregon, California, and British Columbia.
How big does Alisma lanceolatum get?
The plant typically reaches about 0.7 meters in height with a spread of roughly 0.25 meters. Its individual leaves measure between 12 and 20 centimeters long and about 4 centimeters wide.
When does Alisma lanceolatum bloom?
Flowering occurs from June through August, producing small pinkish-purple flowers. This makes it a mid-to-late summer bloomer in its native habitats.
Is Alisma lanceolatum considered invasive?
Yes, in several regions it is classified as a noxious weed and is particularly troublesome as a rice-field pest in places like New South Wales and California. In the British Isles it ranges from occasional in England and Wales to very rare in Scotland.
More in Aquarium and Aquatic Plants, Part 3 1-24
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