Alleopathy, Elodea & Hornwort in the aquarium.

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 It seems that I will be looking for ways to lower nitrates and control algae forever.  I have always grown Hornwort faster than I could give it away or feed it to the Barbs.  HW doesn't like to be planted, and I wanted another native that would grow vertically in the background.  I added Elodea.  As the Elodea began to establish itself, I noticed that the Hornwort was diminishing.  The Elodea wasn't happy being planted either. The floating mass began producing numerous vertical roots, and the HW began dying. It was a great look while it lasted. 

Recent reading indicates that both plants have alleopathic properties,  Attempts to repopulate the HW with plants from other tanks failed.  Is it possible that the Elodea was responsible, or just a contributor?  Nitrates remain somewhere between  40-50.

[anewbie]

I'm not happy with Elodea in general; but i have it with hornworth and in my tank hornworth easily outgrows the elodea. A plant that might fit your need (and is also sold at aquarium co-op) is pogostemon Stellatus octopus:

https://www.aquariumcoop.com/collections/live-plants/products/pogostemon-stellatus-octopus

 

This is an easy to grow stem plant. Just cut it from time to time and it will branch out and grow nice and bushy. It just takes a while. If  you can get it to grow above the water line it will produce a fantastic purple flower.

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As to your question - I know hornworth is said to constrained other plants but I never had a problem with elodea interfering. My tank with hornworth is a low tech tank with guppies and the stuff just grows and grows. The elodea is a bit slower but i keep it heavily constrained since i generally dislike the plant. What could have happened is if it somehow blocked light from hornworth or some other nutrient is in limited supply it might have sucked it up... 

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On 8/27/2021 at 4:00 PM, anewbie said:

This is an easy to grow stem plant. Just cut it from time to time and it will branch out and grow nice and bushy. It just takes a while. If  you can get it to grow above the water line it will produce a fantastic purple flower.

I bought PSO from the Coop in February It grew very well until I separated the the individual plants.  The PSO in the planted tank will soon be # 12 on my list of the fallen.  I still have two more stems to work with in different tanks.  It occurred to me that some plants may require a pruning in order to establish themselves in their new environment.  Id like to see that flower on one of my plants.