Can I grow this in a container?

Yes, it thrives in a pot submerged in a pond.

Does it need full sun?

It prefers full sun for the best flowering performance.

Plant guide

Flowering rush.

Butomus umbellatus

Pronounced BOO-toh-mus um-bell-AY-tus

Also known as Flowering Rush, Flowering-rush

The flowering rush is a lovely aquatic perennial that brings a touch of elegance to pond edges. It produces beautiful clusters of pink flowers atop tall, slender stems. You will find it thrives best when planted in shallow water or very moist soil.

At a glance

Care level: Easy
Plant type: Aquatic perennial
Light: Full sun to partial shade
Indoor light: Direct sun
Water: Every day
Mature size: 5 feet
Growth rate: Fast
Hardiness: USDA 5 to 9
Bloom time: Mid to late summer

Care

Keep the roots submerged in shallow water or ensure the soil remains consistently saturated. Watch for yellowing leaves which often signal the plant needs more nutrients or deeper water. It is a vigorous grower so keep an eye on it to prevent it from crowding out other plants.

Watering: The soil must remain constantly wet or submerged in up to 10 inches of water.
Feeding: Use an aquatic plant fertilizer tablet pushed into the soil during the growing season.
Pruning: Trim back dead or yellowing foliage in late autumn to keep the area tidy.
Repotting: Divide the rhizomes every couple of years to prevent the container from becoming overcrowded.
Soil: Heavy loam or aquatic soil
Soil pH: 6.0 to 8.0
Temperature: -25 to 35°C
Humidity: 60 to 100%
Drought tolerance: Low
Lifespan: Perennial, long lived in ideal aquatic conditions.
Deer and rabbits: Moderate

Signs it needs repotting

Roots growing out of the pot drainage holes
Reduced flowering
Plant becoming overcrowded in the container

Safety

People: The plant is generally considered non-toxic, though raw rhizomes may cause digestive upset.
Children: The sharp leaf margins can cause small cuts, so keep children away from dense stands.
Contact allergens: The leaves have sharp, stiff edges that can cause minor skin abrasions.
Airborne allergens: There are no notable respiratory allergens associated with this plant.
Edibility: The rhizomes are edible only after thorough cooking, but raw consumption is not recommended.

How to identify it

Tall, grass like triangular leaves
Clusters of pink umbrella shaped flowers
Grows from thick underwater rhizomes
Reaches heights of 3 to 5 feet

Height: 0.6 to 1.5m
Spread: 0.3 to 0.6m
Leaves: green, deciduous
Flowers: pink, white, 2 to 3cm
Fruit: brown, Late summer

Problems to watch for

By symptom

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Growing it

Propagation: division, seed
When to plant: spring, early summer
Overwintering: If in a container, lower the pot deeper into the pond to prevent the roots from freezing solid. If in the ground, it will naturally die back and return in spring.
In containers: It grows well in aquatic pots submerged in 5 to 15 centimeters of water.

Division

1. Carefully lift the plant from the water in spring.
2. Use a sharp knife to divide the rhizome into sections with roots.
3. Replant the sections into aquatic soil at the same depth.

Group with other marginal aquatic plants to create a naturalistic pond edge.

Grows well with

Pickerelweed · It provides a nice contrast in leaf shape and flower color.
Cattail · They share similar moisture requirements in a pond setting.

Similar species

Arrowhead · Both are common marginal plants with distinct foliage.

Science

Family: Butomaceae
Genus: Butomus
Order: Alismatales
Class: Liliopsida
Native range: Eurasia
Conservation: It is considered an invasive weed in many parts of North America and should not be planted near natural waterways.

It grows in shallow, slow moving water where it spreads via rhizomes to form dense colonies.

Value to wildlife: nectar source, shelter for aquatic insects
Pollinators: bees, butterflies
Uses: ornamental pond plant, bog garden accent

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 1/9
Soil reaction: 6/9
Light: 8/9
Temperature: 5/9
Moisture: 9/9
Nutrients: 6/9

Taxonomy resolved against GBIF.

Questions people ask

Can I grow this in a container?: Yes, it thrives in a pot submerged in a pond.
Does it need full sun?: It prefers full sun for the best flowering performance.

Where the name comes from

The name Butomus comes from the Greek words for ox and cut, referring to the sharp leaves that can cut a cow's mouth.

Good to know

It is the only member of the Butomaceae family.
The flowers are arranged in an umbel, which gives it its specific epithet.
It can grow fully submerged or in shallow water.

Keep your flowering rush growing

This page is a general guide. Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked.

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.