Is This Blanketweed?

[mark4785]

Hello,

For the past 6 months some sort of weed has been growing in my pond. It has travelled all the way around the pond (attached itself to the base and all walls of the pond) and frequently gets sucked into the pump that powers the water feature. I have taken numerous photos of it with the aim of identifying what it is, whether it has any positive/negative impact on the pond (i.e. is it good at absorbing ammonia/nitrates?) and whether it its a hazard to various pond fish. The fish have been hiding within the weed over the winter period, I am scared it will go into their gills and get stuck.

Another concern is whether the weed dies off during a certain season. If so, will ammonia poisoning occur if I don't promptly remove it when it is decomposing?

Here are the pictures:

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[Tokis-Phoenix]

Yep thats blanketweed- it can grow at a very fast rate.

Pros;
1. Due to being a plant of sorts it will help absorb nitrates.
2. If you want to breed goldfish in your pond it makes a great places for them to spawn on and for tiny fry to hide in during their most vulnerable/tiny phase of life. Goldfish can be very prolific breeders though during spawning time so you may end up having more fry on your hands than what you want.

Cons;
1. It does die back a lot during the winter (if you have colds winters where you live, i'm not sure what it would do in a warm climate during wintertime) which if you have very large quantities of the stuff can cause water quality issues as it decomposes very quickly into a sludge at the bottom of the pond.
2. You can help reduce its spread by having more large established pond plants in the garden, however if you wanna completely get rid of it i believe you have to use chemicals. However just like it dieing off in large quantities in the winter can be a problem, chemicals causing it all to dramatically die off can also cause the same problem. So if you are planning on completely eradicating it, its best to remove as much of it by hand first before using any chemicals.

Having said that though i get it in my pond during the summer and it so far hasn't presented any big problem. I have lots of large established pond plants in the pond which help naturally keep it in check (to a certain extent) as they are more efficient at absorbing the nitrates it needs to survive than it is. I did still go out a few times last year to pull some of it out (i was concerned about it clogging up the filter pump)- on the plus side it composted very quickly in my compost bin helping make great soil for the flower beds !

 

[mark4785]

Thank you for clarifying all of that Tokis-Phoenix.

At present there is only one marginal pond plant submerged in the pond, and it isn't growing season for it, although it hasn't lost its colour etc. I think I will follow your advice and occassionally take some of the blanketweed out by hand to keep it under control and add 1-2 more small plants to further keep it under control. The last time I checked, the nitrate level was above zero within the pond (before the blanketweed grew) so I will definitely keep a substantial amount of blanketweed within the pond so that it continues to absorb those toxins. I suppose the weed is also a good winter bedding for fish as I've read that hibernating fish can often suffer from wounds as a result of friction on the base of the pond.

Again, thanks for the advice.