How to Grow Spike Cordgrass

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Spike Cordgrass

Distichlis spicata

grass

Spike cordgrass is a salt-tolerant perennial grass native to coastal marshes and alkaline wetlands across North America. It forms dense, creeping mats with stiff, upright culms and distinctive two-ranked (distichous) leaf arrangement. This hardy grass thrives in conditions where few other plants survive, making it invaluable for erosion control and habitat restoration.

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Example Spike Cordgrass timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Spike Cordgrass

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Spike Cordgrass

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Spike Cordgrass dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6+ hours daily (tolerates partial shade but performs best in full sun)
💧
Water: Prefers consistently moist to wet soils; naturally thrives in marshes, salt marshes, and alkaline wetlands. Tolerates periodic flooding and saline water. Once established, very drought-tolerant due to deep rhizome system.
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Spacing: 12-18 inches for plugs or divisions; seeds require wet stratification and broadcast seeding at 10-15 lbs per acre inches
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Days to maturity: Year 1-2 for establishment; reaches full density in 2-3 years
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Planting depth: Seeds: direct sow on moist soil surface or press lightly into soil; Plugs/divisions: plant at same depth as in original container

Soil

Type: Sandy, silty, or clay soils with high salt tolerance; prefers consistently moist to wet soils
pH: 6.0-8.5 (tolerates neutral to slightly alkaline conditions)
Amendments:
Minimal amendments needed; naturally adapted to poor soils Organic matter can improve moisture retention in sandy soils Tolerates and even prefers saline conditions

Growing Zones

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Thrives across zones 3-10; most vigorous in zones 5-9

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a

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Growth Stages

1

Establishment

3-6 months

Seedlings or newly transplanted divisions develop initial rhizomes and shoot growth. Plants are slow-growing initially.

Keep soil consistently moist. Protect from foot traffic. Mulch lightly if needed to retain moisture around new plantings.

2

Rhizome Development

6-18 months

Extensive underground rhizome network expands laterally, creating interconnected mat structure. Above-ground growth becomes more visible.

Maintain moisture levels. Allow natural rhizome spread. No fertilizer typically needed.

3

Vegetative Growth

Spring through early summer

Dense, uniform turf develops with stiff, blue-green culms typically 8-24 inches tall depending on soil moisture and salinity.

Can tolerate periodic mowing if needed for management. Performs well with minimal maintenance once established.

4

Flowering

Late July through September

Distinctive compact, spike-like panicles emerge (hence the common name). Flowers are inconspicuous but seed heads are characteristic.

Flowering occurs in late summer. Allow seed heads to mature if wildlife food is desired.

5

Dormancy

October through April

Foliage turns golden-tan to brown in fall and winter; persists through winter providing erosion protection and wildlife cover.

Leave standing for winter habitat value. Spring growth resumes as soil warms.

Companion Planting

Plan your garden →

Plant with:

Black needlerush (Juncus roemerianus) Salt marsh hay (Spartina patens) Smooth cordgrass (Spartina alterniflora) High-tide bush (Iva frutescens) Glasswort/Samphire (Salicornia virginica) Sea oats (Uniola paniculata) Marsh elder (Iva frutescens)

Avoid planting near:

Freshwater-dependent species (requires different water chemistry) Lawn grasses incompatible with saline/alkaline conditions

Common Pests

  • Rarely problematic; tolerate or use spinosad if populations become severe

  • Natural predators usually control; horticultural oil spray if necessary

  • Improve air circulation; rarely requires treatment in natural wetland settings

Uses

🏠

Erosion Control & Shoreline Protection

Household

Spike cordgrass is widely used in coastal restoration projects to stabilize marsh edges, prevent soil erosion, and reduce wave action. Its rhizomatous network binds soil effectively and can withstand storm surge. [source]

🦋

Wildlife Habitat & Food Source

Wildlife

Provides critical nesting habitat for marsh birds and ground-nesting species. Seeds and foliage are eaten by waterfowl, marsh birds, and small mammals. The dense mat offers shelter for insects and invertebrates. [source]

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Salt Marsh Restoration

Household

A keystone species for wetland and salt marsh restoration projects, particularly valuable for ecological rehabilitation in coastal areas and inland alkaline wetlands. [source]

🏠

Bioswales & Stormwater Management

Household

Used in constructed wetlands and bioswales to filter runoff, reduce peak flows, and improve water quality in coastal and saline conditions. [source]

💊

Traditional Use & Forage

Medicinal

Historically harvested and dried as salt marsh hay for livestock forage in coastal regions. Contains minerals and salt tolerance beneficial for livestock in salt-affected areas. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Spike cordgrass is not harvested for food. For erosion control and stabilization projects, allow 2-3 years for full mat establishment. For seed collection (for restoration projects): harvest mature seed heads in late September through October by hand-stripping or cutting; air dry and store in cool, dry conditions.

Fun Facts

  • 🌱 Spike cordgrass is one of the few plants that thrives in hypersaline conditions—some populations tolerate salt concentrations higher than seawater itself.
  • 🌱 The plant's distinctive two-ranked leaf arrangement (distichous) gives both its genus name Distichlis and its characteristic appearance, with leaves arranged in two opposite rows along the stem.
  • 🌱 This grass has an exceptional ability to regulate internal salt: it secretes excess salt through special glands on its leaf surface, allowing it to survive and even dominate in salt marshes where most plants cannot survive.

Gardening Terms

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