Southern Naiad

Najas guadalupensis
Native Submerged
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Quick ID Summary
What It Looks Like
Many small leaves along the stem, only about 1 inch long, arranged in whorls and getting gradually smaller toward the tip. Stems up to 2 feet.
Where It Grows
Throughout the United States, in water up to 15 feet deep if the water is clear.
How It Spreads
Dies back each year and repopulates from seed. Spreads easily by fragmentation.
Status
Native. Provides habitat for young fish and invertebrates. Also called bushy pondweed and guppy grass.
Sprig of southern naiad held above a lake
Southern Naiad — Najas guadalupensis

Identification

Southern naiad is a small-leaved submerged plant. It produces many small leaves along the stem - the leaves are only about 1 inch long - and they get gradually smaller toward the tip of the stem. The leaves are arranged in whorls. Stems grow up to 2 feet in length.

It occurs throughout the United States and grows in water up to 15 feet deep where the water is clear.

Telling Naiad from Sago Pondweed

Naiad is often confused with sago pondweed, and the arrangement settles it. Southern naiad leaves are arranged in whorls; sago pondweed leaves are arranged oppositely in sheaths. Leaf length helps too - naiad leaves are about 1 inch, while sago pondweed leaves can vary from 1 to 6 inches.

Why It Matters

This pond weed is native to the United States, and naiad provides habitat for young fish and invertebrates. Because it can spread easily through fragmentation, close management is recommended rather than eradication.

Its annual habit is worth knowing: southern naiad dies back each year and repopulates from seed. A clear pond in late season does not mean the seed bank is gone.

Control Approach

Light. Pond dye as an early season application - before growth begins, maintained throughout the year.

Biological. Grass carp can eat 2 to 3 times their own body weight in vegetation each day.

Chemical. Fast contact options and slower whole-pond systemics are both available; the choice depends on whether you can treat the whole waterbody and how quickly you need the result.

Recommended Treatment Products

These are the products Natural Waterscapes recommends for southern naiad, with the role each one plays. Read the label and confirm the product suits your waterbody before applying.

Early Season, Light Control
Pond Dye
Applied before growth begins and maintained throughout the year.
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Quick Results, No Restrictions
Aquathol K
Provides excellent control with quick results and no water use restrictions after use.
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Granular Option
Aquathol Super K
The granular form, with the same quick results and no water use restrictions.
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Results Under 1 Week
Propeller
Provides excellent control of naiad, with results in less than 1 week.
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Kills to the Root
Sonar AS
Takes 30 to 60 days and kills to the roots. The entire pond must be treated, and it is only for ponds with little or no flow.
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Ready to Use
Sonar RTU
The ready-to-use form of the same root-killing treatment.
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Granular
Sonar One
The granular form of the same root-killing treatment.
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Broad Spectrum
Duckweed Destroyer
A fast-acting, broad spectrum option for ponds with several weed species.
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Common Questions

How do I tell southern naiad from sago pondweed?

Southern naiad leaves are arranged in whorls. Sago pondweed leaves are arranged oppositely in sheaths. Naiad leaves are about 1 inch long; sago leaves vary from 1 to 6 inches.

Is southern naiad native?

Yes. It is native to the United States and provides habitat for young fish and invertebrates.

Does southern naiad come back every year?

It dies back each year and repopulates from seed.

How deep does southern naiad grow?

In water up to 15 feet deep, if the water is clear.

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Need help with southern naiad?

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