Emersed vs. Submersed Growth

Aquatic plants often grow in areas that are subject to constantly changing water levels, so most have the ability to grow both submersed and emersed (rising above the surface of the water). The benefit of growing plants emersed is that they grow much faster above water. In fact, this is how most aquatic plant nurseries grow their plants. However, emersed growth is much different physically than submersed growth. Leaves that function above water won't be able to survive underwater and vice versa. This is also why plants grown emersed will often die back and look completely different when they grow back in their submersed form. This is a critical stage for the plant, and also for your aquarium. Make sure to remove any dying leaves or stems so they don't pollute the water. It will take anywhere from a week to a month for a plant to adapt to its submerged form. Leaves are often smaller and thinner, and stems are much less thick since they no longer have to provide as much structural support for the plant. A plant will often look and behave completely differently in its submersed form. Take Lobelia cardinalis for example:

Emersed


Submersed

You'll find that many plants flower when they grow emersed, as polination is obviously quite hard to accomplish while submersed! In the next article, I'll discus how to set up an emersed growing tub so you can experiment with speedy emersed growth to quickly expand the amount of a plant you might have.