Native grasses for wetlands

Rattlesnake Manna Grass – Seeds

Glyceria canadensis

Product code : ​

This native grass forms dense clumps and airy panicles in moist or saturated soil. Exceptionally hardy, Rattlesnake Manna Grass stabilizes shorelines, slows runoff, and supports biodiversity in rain gardens and riparian habitats.
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Detailed plant guide
Advice adapted to Canada
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Quantity
Approximately 200 seeds
Exposure
Full sun to partial shade
Life cycle
Perennial
Hardiness
USDA Zones 3 to 8

Discover the plant

Common nameRattlesnake Manna Grass
FamilyPoaceae
GenusGlyceria
Speciescanadensis
Cultivar​
TypeNative perennial wetland grass
Botanical nameGlyceria canadensis
Reproducible seedsYes

Rattlesnake Manna Grass (Glyceria canadensis) is a native perennial grass of marshes, shorelines, and wet meadows, valued for flexible green foliage and distinctive airy panicles. From July through September, the branched flower clusters carry small greenish to yellowish spikelets that gradually develop brown tones and resemble delicate rattles. Plants generally reach 60 to 120 cm tall and form broad, dense, slightly arching clumps. Exceptionally hardy in Zones 3 to 8, this species returns reliably after severe Quebec winters and brings movement, texture, and a natural presence to rain gardens, wetland plantings, and ecological landscapes throughout Canada.

Rattlesnake Manna Grass prefers full sun or partial shade and loamy to clay soil rich in organic matter that remains consistently moist, saturated, or periodically flooded. It tolerates temporary inundation and seasonal fluctuations in water level exceptionally well. Surface sow the seeds in spring or autumn, pressing them gently against moist growing medium without burying them deeply. Maintain constant moisture throughout germination and seedling establishment. A thin layer of compost is sufficient in poor ground, while naturally fertile wet soil requires little additional feeding. Do not allow the site to dry during active growth, especially while young plants are developing their root systems.

In the garden, Rattlesnake Manna Grass suits rain gardens, shoreline buffers, vegetated ditches, pond margins, and wetland restoration projects. Its dense root system helps stabilize saturated soil, slow runoff, and reduce surface erosion. The clumps provide shelter for birds, amphibians, insects, and other organisms associated with riparian habitats. Pair it with Northern Blue Flag Iris, Cardinal Flower, Spotted Joe-Pye Weed, and Water Avens to create a diverse native planting. The airy panicles and seed-bearing stems also extend ecological and ornamental interest into autumn, making Glyceria canadensis especially valuable in biodiversity-focused Canadian landscapes.

Glycérie du Canada, graminée indigène de milieu humide.

Sowing guide

It all startswith a seed.

Sowing depth

Surface sow

Spacing / density

45 to 60 cm (18 to 24 in)

Germination temperature

15 to 20°C

Germination time

14 to 30 days after stratification

Sowing period

Autumn or spring

Propagation

Seed or clump division

Cold stratification

Yes

Growing method

Surface sow Rattlesnake Manna Grass seeds in autumn or spring on a consistently moist growing medium. Germination is typically rapid when the seeds remain in constant contact with moisture. This native grass thrives in organically rich loamy to clay soils and tolerates temporary flooding exceptionally well. Grow in full sun to partial shade and maintain moist soil throughout the growing season. Once established, it stabilizes wet soils, improves shoreline habitats, and is one of the best native grasses for ecological restoration projects throughout Canada.

Soil and care

The right care,at the right time.

Soil pH

Approximately 5.5 to 7.5

Minimum temperature

Approximately -40°C

Care level

Low to moderate

Watering

Abundant and regular; keep soil moist

Soil type

Loamy to clay, rich, moist to saturated

Fertilization

Light spring compost only when needed

Moisture

High; wet to saturated soil

Seasonal care

In spring, cut back dry stems before new growth emerges and remove debris that could smother the crown. Apply a thin layer of compost only when the soil is poor. Throughout summer, keep the site consistently moist and water deeply if a shoreline area temporarily dries. Remove competing weeds around young plants. In autumn, leave part of the panicles and foliage standing to shelter wildlife and maintain winter structure. Divide clumps that have become overly broad in spring or early autumn, taking care to keep the divisions moist during transplanting.

Container growing

A garden,within reach.

Recommended pot size

30 to 45 cm (12 to 18 in)
Rattlesnake Manna Grass can be grown in a large container with excellent drainage and a generous water reservoir. Use an organic-rich growing medium and maintain constant moisture throughout the growing season. Although it performs best in the ground where its roots can spread through wet soils, container culture is suitable for rain gardens, water features, and ecological landscapes.
Glycérie du Canada, graminée indigène de milieu humide.

Bloom and dimensions

Its place,in your garden.

Mature height

Approximately 120 cm

Width / spread

Approximately 120 cm in an established clump

Flower color

Greenish yellow maturing to brown

Foliage color

Green

Foliage type

Deciduous

Growth rate

Moderate to fast

Growth habit

Upright, clumping and rhizomatous

Fragrance

Little to no fragrance

Bloom period

July to September

Fruiting

Caryopses held on branched panicles

Days to maturity

Usually reaches full size and flowers in the second year

Harvest

August to September
Glycérie du Canada, graminée indigène de milieu humide.

Garden associations

In goodcompany.

Companion plants

Northern Blue Flag Iris, Cardinal Flower, Spotted Joe-Pye Weed, and Water Avens

Plants to avoid

Lavender, cotton lavender, Blanket Flower, and dry-soil plants

Frequently asked questions

Your questions,answered.

When should Rattlesnake Manna Grass seeds be sown?
Rattlesnake Manna Grass seeds can be sown in spring or autumn on a consistently moist growing medium. Surface sowing ensures the seeds benefit from both light and moisture.
Does Rattlesnake Manna Grass grow in saturated soil?
Yes. It is naturally adapted to marshes, wet ditches, riparian buffers, rain gardens, and other wetland habitats.
Can it stabilize a wet shoreline?
Yes. Its dense root system effectively stabilizes shorelines and reduces erosion in wet soils.
Does Rattlesnake Manna Grass attract pollinators?
Yes. It provides food, shelter, and breeding habitat for numerous wetland birds, beneficial insects, and other wildlife.
How should a mature clump be maintained?
Very little maintenance is required. Simply remove the previous season's dry stems in spring and maintain adequate soil moisture during establishment.

Wildlife and pets

Life,around your plants.

Attracts birds

Yes

Native plant

Yes

Supporting wildlife

Beneficial wildlife