Phragmites (Common Reed) Identification & Treatment
Scientific Name: Phragmites australis subsp. australis (invasive) vs. P. australis subsp. americanus (native) Category: Emergent Tier: 1 — High-Priority — Most prevalent and/or most damaging across the US
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Identification
Phragmites is a very tall (6–15+ feet) grass with stiff, hollow stems, flat blue-green to gray-green leaves, and a large, feathery, plume-like seed head at the top. Forms dense, impenetrable monoculture stands that exclude nearly all other vegetation. Key distinguishing features:
- Very tall (often 10+ feet), stiff, hollow stems
- Large feathery plume at top (tan to purplish when fresh, gray when dry)
- Dense stands with thick leaf litter beneath
- Invasive form has dull, grayish-green leaves; native form has reddish-brown stems and darker green leaves
Invasive vs. Native: The invasive European subspecies (australis) has tan, smooth stems, blue-gray leaves, and dense, persistent stands. The native subspecies (americanus) has reddish-brown stems, darker green leaves, and grows in less dense stands intermixed with other species. The native form is declining and should be preserved.
Treatment
Recommended Natural Waterscapes Products:
- Cattail Killer Pack — Also effective for Phragmites control. Cattail Killer Pack
- Glyphosate 5.4 — Apply in late summer/early fall when plants are actively translocating to rhizomes. Most effective method. Cut stems to 6 inches and apply to cut stems for best results. Glyphosate 5.4
- Clearcast (imazamox) — Systemic herbicide that can be used near water. Clearcast
Important: Dead Phragmites stalks pose a fire hazard. Remove dead material after successful treatment. Multi-year follow-up is essential — rhizomes can survive multiple treatment rounds.
Full Profile
- Native Range: Invasive form — Europe. Native form — North America.
- US Distribution: All 48 contiguous states. Especially problematic in EPA ecoregions: Northern Appalachian/Atlantic Maritime, North Central Hardwood Forests, Atlantic Coastal Pine Barrens, Great Lakes region. USDA Zones 3–10.
- Regulatory Status: Invasive subspecies listed as noxious or invasive in many states. Not on Federal Noxious Weed List.
- Habitat: Pond and lake margins, wetlands, roadside ditches, tidal marshes, riverbanks. Tolerates fresh to brackish water. Thrives in disturbed areas with exposed soil.
- Reproduction: Aggressive rhizome network (can extend 60+ feet from the parent stand per year). Also spreads by stolons and fragments. Seeds are generally not a major reproduction pathway.
- Ecological Benefits: Native Phragmites provides valuable wetland habitat. Invasive Phragmites forms monocultures that drastically reduce plant and animal diversity. However, even invasive stands provide some nesting habitat for certain bird species (marsh wren, red-winged blackbird) and can stabilize eroding shorelines. In most management scenarios, replacing invasive Phragmites with a diverse native plant community is the goal.
- Seasonal Behavior: Rapid spring growth from rhizomes. Peak height and flowering in late summer. Seed heads persist through winter. Dead stalks remain standing for 2+ years if not removed.
Sources: Texas A&M AquaPlant – Common Reed | MSU Extension
Related Species
- Cattails (Typha latifolia (broadleaf), T. angustifolia (narrowleaf), T. × glauca (hybrid)) — Emergent, Tier 1
- Creeping Water Primrose (Ludwigia spp. (L. peploides, L. grandiflora, L. repens)) — Emergent, Tier 1
- Dollar Weed (Pennywort) (Hydrocotyle spp. (H. umbellata, H. ranunculoides, H. verticillata)) — Emergent, Tier 2
- Alligator Weed (Alternanthera philoxeroides) — Emergent, Tier 2
- Flowering Rush (Butomus umbellatus) — Emergent, Tier 3
- Purple Loosestrife (Lythrum salicaria) — Emergent, Tier 3
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