Floating sweet-grass.

At a glance

Care level

Easy

Plant type

Aquatic grass

Light

Full sun to partial shade

Indoor light

Bright indirect

Water

Every day

Mature size

3 to 4 feet

Growth rate

Fast

Hardiness

USDA 4 to 9

Bloom time

Late spring to mid summer

Care

Keep the soil consistently saturated or submerged to mimic its natural wetland home. Watch for yellowing leaves, which often signal that the plant has dried out too much. It is quite hardy and rarely needs extra attention once established.

Watering

The soil must remain constantly wet or submerged at all times.

Feeding

Apply a balanced aquatic plant fertilizer during the active growing season.

Pruning

Trim back dead or overgrown stems in late autumn to keep the area tidy.

Repotting

Divide the root clumps if the plant becomes too crowded in its container.

Soil

Wet, heavy, or boggy soil

Soil pH

6.0 to 7.5

Temperature

-20 to 30°C

Humidity

70 to 100%

Drought tolerance

Low

Lifespan

Perennial, typically 3 to 5 years.

Deer and rabbits

Moderate

Safety

People

There are no known toxic properties for humans.

Children

The plant is safe to handle, but children should be supervised near deep water where it grows.

Contact allergens

The leaves can have slightly rough edges that may cause minor skin irritation.

Airborne allergens

Like many grasses, the pollen can trigger hay fever in sensitive individuals.

Edibility

While historically used as a grain, ensure the water source is clean and free of pollutants or parasites before considering consumption.

How to identify it

• Long, floating ribbon like leaves
• Tall, slender flowering stems
• Bright green foliage color
• Grows in shallow water
• Spreading rhizomatous root system

Height

0.3 to 0.9m

Spread

0.3 to 0.6m

Leaves

green, deciduous

Flowers

green, purple, 10 to 30cm

Fruit

brown, Late summer

Problems to watch for

• Aphids · Small insects that may cluster on the stems during dry spells.

Growing it

Propagation

division, seed

When to plant

spring, autumn

Overwintering

The plant will naturally die back to the mud in winter. You do not need to do anything, as it is hardy and will regrow in spring.

In containers

It grows well in aquatic containers placed in shallow water features.

Group this with other moisture loving plants to create a naturalistic bog garden transition.

Grows well with

• Yellow Flag Iris · It shares similar moisture requirements and provides a nice vertical contrast.
• Marsh Marigold · They both enjoy the wet conditions of a pond edge.

Similar species

• Reed Sweet Grass · It is a much larger and more aggressive relative.

Science

Family

Poaceae

Genus

Glyceria

Order

Poales

Class

Liliopsida

Native range

Europe, North Africa, and parts of Asia.

Conservation

It is widespread and not currently of conservation concern.

It survives by rooting in saturated mud and using its hollow stems to stay buoyant in shallow water.

Value to wildlife

provides cover for aquatic life, seeds are food for waterfowl

Pollinators

bees

Uses

aquatic garden plant, wetland restoration, wildlife habitat

Taxonomy resolved against GBIF.

Questions people ask

Can I grow this in a standard garden bed?

No, it requires consistently wet soil or standing water to survive.

How deep should the water be?

It prefers shallow water up to 15 centimeters deep.

Where the name comes from

The name Glyceria comes from the Greek word for sweet, referring to the taste of the seeds, while fluitans means floating.

Good to know

• It thrives in shallow water or mud.
• The stems are hollow and can float on the water surface.
• It is a perennial grass that spreads by rhizomes.