Troubleshooting
Ivy-leaved Duckweed problems — and how to fix them
Ivy-leaved Duckweed (Lemna trisulca) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Surface mat formation at flowering
When plants briefly surface to flower, they can temporarily form a surface mat. This is a natural behaviour; skim lightly if it shades submerged planting or fish, but avoid removing all surface material.
Loss in high-flow conditions
Unlike surface duckweeds, Lemna trisulca can be swept away or broken apart in moderate currents. Suitable only for still or very slow-moving water — ponds, lake margins, and aquaria with low pump flow.
Competitive exclusion by Lemna minor
If common duckweed (Lemna minor) is also present, it can outcompete the submerged trisulca at the surface. Remove surface duckweed periodically to allow light penetration to the submerged colonies.
Prevent ivy-leaved duckweed problems before they start
Most ivy-leaved duckweed issues are care-mismatch, not bad luck. Dial in the basics:
Ivy-leaved Duckweed problems — FAQ
Why is my ivy-leaved duckweed surface mat formation at flowering?
When plants briefly surface to flower, they can temporarily form a surface mat. This is a natural behaviour; skim lightly if it shades submerged planting or fish, but avoid removing all surface material.
Why is my ivy-leaved duckweed loss in high-flow conditions?
Unlike surface duckweeds, Lemna trisulca can be swept away or broken apart in moderate currents. Suitable only for still or very slow-moving water — ponds, lake margins, and aquaria with low pump flow.
Why is my ivy-leaved duckweed competitive exclusion by lemna minor?
If common duckweed (Lemna minor) is also present, it can outcompete the submerged trisulca at the surface. Remove surface duckweed periodically to allow light penetration to the submerged colonies.