Was searching for an enchinodorus that could grow emersed leaves for in my tank remembered this threat came here to find out it is an kleiner bär, what is klein (small) about this?
I guess it depends how and where you grow it.. In submersed form it keeps relatively small.. I'm also growing it emersed outdoor in a basket but rather shallow. Than it also stays a lot smaller, not in leaf size but in stem lenght. It's a very addaptable plant sp. and its size is depended on the depht it is planted in. If planted in deep water it transitions to submersed form first, than if these leaves grow up to a 30cm tall. In this case the leaves also reached the watersurface at this lenght sticking a leaf tip into the atmosphere.
What i find most remarkable is the plant seems to sense this. When the submersed form leaf tips start to dry out, it seems this damage is a stress signal for the plant saying here is the surface and it wants to grow emersed. The plant is triggered to start growing a tiny emersed grow form leaf on a stem from iits rosette. Than this stem keeps growing rather fast towards the surface with a tiny leaf to it. Once the stem made it that far and the leaf is finaly emersed, this leaf starts growing bigger and the stem even longer.
Offspring from this plant that is planted in more shallow water grow much shorter leaf stems yet also not taller than +/- 30cm.
Ive seen very tall discus tanks growing out Echinodorus like this.
I guess it isn't Kleiner bär but it grew in the same fasion. It's final tallness is definitively related to the planting depth. Another tank, don't know if it serves the right to be called discus tank but it contains them and also an E. palaefolius var. latifolius.
https://nl.pinterest.com/pin/165366617541104629/
And this is an E. palaefolius var. latifolius grown in my livingroom with only wet feet. Rather small, it has no need to grow long stems.
And most likely it's size depends on humidity and also maturity when grown emersed in a proper climate.. Artificialy this is difficult in the northern hemisphere. Because it always recieves a negative set back during the winter without enough artificial light and proper humidity. Than it has to start over again next summer keeping rejuvinating the plant and stays relative small.
Also light is an important factor, the kleiner bär from the tank in this topic grew under rather high light. The last 6 months it grew without any artificial light and only some indirect day light. And it was slowly turning back to submersed form. But it didn't get this far completely because the tank is torn down.
But it definitively was shrinking after the light was taken away.
Currently i'm also playing with
E. Regine Hildebrandt.. That is a rather small cultivar very easy.. But not sure if it will suite your ideas and it grows agonizingly slow. It's a cross breed from E. ozelot x E. uruguayensis. Maybe taking one of these is a beter option..