New England’s lakes, ponds, and wetlands are ecological treasures, but they also face increasing pressure from invasive aquatic weeds. Whether you're managing a private pond in Massachusetts, a community lake in Connecticut, or a wetland in New Hampshire, knowing what’s growing in your waterbody is critical to keeping it healthy and functional.
At Water and Wetland, we specialize in aquatic plant management throughout New England. In this guide, we’ll help you identify the most common types of aquatic weeds found throughout the region and explain what to do if they start causing problems.
Why Aquatic Weed Identification Matters in New England
Native aquatic plants are essential for a healthy water ecosystem. They stabilize sediments, support native fish, and filter nutrients. However, invasive species like Eurasian watermilfoil, fanwort (Cabomba), and curly-leaf pondweed have become major threats to waterbodies across New England.
Accurate pond weed identification helps you:
- Detect early-stage infestations
- Apply the right control method
- Minimize impact on beneficial vegetation
- Improve water clarity and habitat health
Understanding what’s in your pond or lake can make the difference between a balanced ecosystem and a weed-choked shoreline.
Four Main Categories of Pond Weeds
1. Algae (Including Harmful Algal Blooms)
Algae can be beneficial at low levels, but in nutrient-rich environments, they can explode into harmful algal blooms (HABs), especially during the summer months.
- Common types: Filamentous algae, blue-green algae (cyanobacteria/Microcystis)
- Found in: Farm ponds, stormwater basins, and shallow lakes
- What to watch for: Green slime, foul odors, scummy surface mats
Note: In Massachusetts and Rhode Island, HABs are increasingly linked to nutrient runoff and warmer temperatures.
2. Floating Aquatic Plants
Floating plants drift on the surface and spread rapidly in calm, nutrient-rich waters.
- Where found: Residential ponds, slow-moving streams, wetland edges
- Warning signs: Thick surface coverage, blocked sunlight, oxygen depletion
3. Submerged Aquatic Weeds
These underwater weeds can create dense mats, tangle fishing gear, and limit recreational access.
- New England invasives: Eurasian watermilfoil, fanwort (Cabomba), hydrilla
- Where found: Deeper ponds, lakes, reservoirs
- What to look for: Feather-like or finely divided leaves, rooted in sediment
Tip: Submerged weeds are often transported between lakes on boat trailers. Always clean your gear.
4. Emergent and Shoreline Weeds
These grow in shallow water or along the edges of wetlands and can rapidly overtake shoreline habitat.
- Common species: Cattails, phragmites, purple loosestrife
- Regional impact: Often dominate native wetlands in Vermont, Maine, and coastal Massachusetts
- What to look for: Tall, reed-like stems; rapid spread along shorelines
When Aquatic Weeds Become a Problem
Aquatic vegetation only becomes a nuisance when it grows excessively or consists of non-native, invasive species. Red flags include:
- Thick mats that hinder boating, kayaking, or swimming
- Rapid spread from year to year
- Fish die-offs or stagnant, low-oxygen water
- Decreased biodiversity or native plant decline
In New England, nutrient runoff from lawn fertilizers, agriculture, and septic systems is a leading contributor to aquatic weed overgrowth.
What to Do If You Spot a Problem
Don’t wait for invasive weeds to take over. At Water and Wetland, we offer comprehensive aquatic vegetation assessments and science-based weed management plans tailored to the unique conditions of New England waterbodies.
Depending on the situation, solutions may include:
- Selective herbicide treatments that protect native species
- Biological controls like triploid grass carp (where allowed)
- Mechanical harvesting for large-scale infestations
- Nutrient reduction strategies to address the root cause
Trust New England’s Aquatic Weed Management Experts
With decades of experience managing aquatic vegetation in Massachusetts, Connecticut, New Hampshire, and beyond, Water and Wetland knows what works in the Northeast. Our licensed specialists use region-specific knowledge to control weeds without compromising your waterbody’s natural balance.
- Need help identifying a weed?
- Concerned about an invasive species in your pond or lake?
- Want a long-term plan for healthy water management?
We’re here to help. Schedule a consultation or use our Aquatic Weed ID Guide to get started.
About Water & Wetland, A Jones Lake Management Partner
Water & Wetland is a trusted expert in lake, pond, and wetland management, providing innovative and environmentally responsible solutions to control invasive species, restore shorelines, and improve water quality. As a Jones Lake Management Partner, we serve HOAs, golf courses, municipalities, and private landowners with customized lake and pond management plans designed to promote long-term ecological health. We understand the importance of proper permitting and regulatory compliance, ensuring that all projects meet local, state, and federal environmental standards. With a commitment to sustainability and science-based practices, Water & Wetland helps clients maintain thriving, well-balanced waterbodies.
