We have some in a bucket outside, it started off as a bucket of trimmings that never got thrown out... You know the story, seemed to good to throw away, but you never do anything with it...
This will be its second winter outside and it grows really thick and not stringy at all, must be the direct sunlight.
Ahh, I remember why it's there now, it was riddled with Utricularia (bladderwort - the fine thread like carnivorous one), so it got turfed out of the community tank.
The Utricularia is still growing strong outside, and there is also some Hydrocotyle and Bacopa growing above the surface of the water as well - I don't know how they survive in the bucket, it's only 25 litres, so the temperature must get pretty warm in the summer.