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Identify Your Weeds

Identify Your Weeds

You cannot treat what you do not know! Identifying your pondweeds is the first step to being successful. Read on for tips.

Successful Weed Control

The more mature your pond, the more you have to deal with weeds. They are not only just annoying, but they can choke the life out of your ecosystem if action is not taken. In order to best treat problematic weeds, you need to positively identify and determine how many types of weeds in your pond.

Most algaecides and herbicides will treat a variety of weeds and algae so it is not always necessary to identify the exact weed but to just determine the class of weeds it belongs to.

Weed Classification

  • Algae: Algae is a cellular plant that is a common nuisance with no distinguishable leaves or root system. Referred to as string algae or pond scum is algae that floats on top of the water in clusters, turn the water green and is often treated by a liquid algaecide. Chara is algae that looks like a submerged weed, but is easy to rake out and has a musky odor with a crunchy texture when handled.
  • Submerged: Submerged plants require water to stand and have a strong root system that is difficult to pull from the water without breaking the soft stems. The majority of the plant will be submerged in the water, however the plant may grow to the surface and spread.
  • Floating: Generally found in shallower water, floating plants can spread and completely cover the surface cutting off light and oxygen to the fish below. They can be divided in two groups: free floating and rooted. A free-floating plant have roots underneath the plant to absorb nutrients from the pond's water, but never touches the bottom, while rooted floating plants often have showy flowers and large leafed foliage that sits on top of the water.
  • Emergent: Rooted plants like cattails, grow along the shoreline and stand above the surface or in shallow areas. Emergent plants may have some of their root system (up to 6-8 inches) in water, however all the leaves will be above water due to the stiff or firm steam.

Sample and Compare

Remove a sample of the weed for a closer look. Try to get some of the roots, steam and leaves and note the color, texture and odor of the plant. Visit our Weed Identification Guide, click on the image that resembles your plant for a detailed plant description, more pictures and treatment recommendations.

Ask an Expert

If you are still unsure, email us at with your attached photos and we will do our best to identify the culprit and recommend the best treatment. Here are our best tips to get a proper identification and treatment option:

  • Take one photo by placing your weed sample in a bucket of water to see movement and leaf structure.
  • Take one photo of the sample in your hand or spread out on a white sheet of paper.
  • Include your state (not all chemicals are approved in every state), how the pond is used (i.e. recreation, irrigation, livestock), if the pond has an outflow and the approximate size of the treatment area.