Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
As for using land plants in the aquarium, here is a quick run-down of what is going on.
1) Many tropical plants live in a sort of in-between world, flooded part of the year, and growing with 'wet feet' the rest of the year. Leaves out of the water.
Some of these plants do better out of water all the time, and make really good house plants. Some of these plants are OK under water all year round, and make fine aquarium plants, even though in the wild they spend part of their life with their leaves exposed to the air. Many Crypts are like this.
Some plants are so much in-between that they will do fine on land, but will hang in there long enough in the aquarium that they are sold as aquarium plants, even though they do not really thrive under water all the time.
2) Many plants live on the margins of lakes and streams, and grow into the water, often floating on the surface. Some of these can also grow under water, and in a low light setting, so make good aquarium plants.
3) Some plants only grow under water except that they will flower when they grow tall enough to reach the water surface. By constantly pruning these plants they keep on growing under water.
4) Stores sell what sells. If they can buy house plants cheap, and sell them as under water plants, they will. When the plants die... a) People do not bother bringing them back, but go buy more plants, or a better light, or buy ferts, or buy a cute little CO2 kit. b) People do bring them back and the store will sell them more plants, lights, ferts or a cute little CO2 kit. It is Win-Win for the store.
Land plants that may be purchased in the nursery, grown in soil, but will do OK in a wetter setting, like an aquarium, or growing out of the top of the tank with just the roots in the water, or as a marginal plant in a pond:
Almost all house plants, but especially Philodendron, Pothos, Maranta, Dracaena, Spatiphyllum, Spider Plant, Spathiphyllum, Wandering Jew.
Here in CA I grow a lot of plants outdoors that others may grow indoors only, but here are the ones that are OK for aquarium or pond use, but usually not as under water plants:
Mondo Grass, Lysmachia nummularia, Most Sedges, reeds and similar plants, including Papayrus. A few specialty Iris like Louisiana and Japanese Iris. Acorus (several species and varieties). Mints of all sorts. (can get invasive in damp soil)
There are a lot more plants that will do just fine in a damp setting, like sitting in a pot in a pond with the leaves out of the water.