Emergent Aquatic Weeds

Emergent Weeds are critically important to many aquatic habitats. They provide spawning areas for adult fish, cover for smaller organisms, and they purify water in wetlands all over the world. Emergent aquatic weeds are also great stabilizers of shoreline areas and they provide a buffer zone, which helps clean the run-off entering the water body. But some are also a nuisance, including invasive species, such as Purple Loosestrife. Below are descriptions of the more common types and their control options:

Cattails (Typha spp.)

This is a very common plant found throughout the USA. Native species of Cattails can grow up to 10 feet tall, but some varieties, like Narrow-leaved Cattails, are not as large. They are beautiful plants with the ability to expand quite rapidly. Generally, the safest and easiest control method is to spray unwanted portions with a mix of Shore-Klear or AquaNeat and a Surfactant in the summer or fall after the seed-heads appear but before the first frost. Dead leaves should be cut off at ground level 2 weeks after application, and new shoots should be sprayed as they reappear. See the Product Selection Chart for alternative treatments.


Spikerush (Eleocharis spp.)

Many species are found throughout the USA. Spikerush are mostly leafless with erect stems and black spikelets on top. They reproduce from rootstock or seed, and are found in marshes and shallow water areas. This plant is excellent at stabilizing soil along lake, pond and stream banks. When the population is too large for manual removal of unwanted growth, the best chemical treatment is Reward. See the Product Selection Chart for alternative treatments.


Bulrush (Scirpus spp.)

Many species of Bulrush occur throughout the USA in wet swales, marshes and shallow areas of lakes and ponds. They have a long stem with clusters of brown flowers and seeds at the end. This plant provides habitat for many types of wildlife and it is the basis of many wetland areas. It is also an excellent species to use to protect lake, pond and stream banks from waves and erosion. If large areas need to be cleared, Navigate can be used, but for spot clearing Shore-Klear or AquaNeat and a Surfactant can be quite effective. See the Product Selection Chart for alternative treatments.


Arrowhead (Sagittaria spp.)

This is a beautiful plant that is very popular for water gardening and planting along earth ponds. As the name suggests, it has arrow-shaped emergent leaves and small white flowers. It is found in shallow water areas, usually along shorelines or in marshes. If chemical control is needed, use Reward. See the Product Selection Chart for alternative treatments.


Pickerelweed (Pontederia cordata)

Only one distinct species of this plant exists naturally in the USA. It has heart-shaped leaves and a violet-blue spike of flowers at the end of one central stem. Vigorous creeping rootstocks allow the plant to form dense stands and make control difficult. Treat early with Reward. See the Product Selection Chart for alternative treatments.


Purple Loosestrife (Lythrum salicaria)

This is a highly invasive species that has encroached into many wetland areas across the northern half of the USA. It crowds out native plant species and destroys biodiversity in the most extreme cases. Control should be initiated as soon as possible. Purple Loosestrife has bright purplish pink, long-lasting flowers that made it popular in the garden trade, which helped to spread it. Purple Loosestrife has stiff, fine-haired stems with leaves oppositely arranged, usually in pairs. Biological control with insects is currently under development, but until then Shore-Klear or AquaNeat mixed with a Surfactant is the control method of choice. Large monocultures of Purple Loosestrife can be sprayed with this mix, but when it is observed creeping into a native stand of vegetation, the “Glove of Death” technique should be considered. Basically, you put on a rubber glove that extends to your elbow and wear a cotton glove over that. Then you dip the cotton glove into the mixture and run it up the plant being careful not to touch the surrounding native vegetation. A Pond Dye should be added to the mixture as a marker to distinguish treated plants from untreated.