Then it was grown emersed as what Rivercats was getting to. Meaning, that the DHG will stall in growth or even melt (turn yellow and brown) before it recovers, acclimates, and grows new leaves for submersed growth.
At least moderate light, ferts, and co2 will help this transition.
I'm only able to grow it my lower light tank with little ferts and no co2 because it is fully acclimated to immersed growth and aqua soil is a type of substrate that has a good amount of nutrients baked in. Otherwise, I don't recommend this.
DHG has grown and carpeted much faster and more lush when I grew in with moderate to high light, co2, and fertilizer dosing that was comprehensive (PPS-Pro or at least Seachem Flourish).