Image via iStock.com/takepicsforfun
By Kenneth Wingerter
It's fairly easy to cultivate most live aquarium (that is, aquatic) plants.
If you keep your aquarium plants well-nourished, as well as provide appropriate lighting and water flow, it should be quite simple to maintain many lush aquarium plant species. But they must be true aquarium plants.
We are seeing a sort of renaissance in the planted aquarium hobby. Aquatic plant enthusiasts presently have a broader selection of species to choose from than ever before.
While choice is always a good thing, there are certain species of plants that may be found in the trade but, nevertheless, are unlikely to flourish under typical aquarium conditions.
Among these are a handful of terrestrial and emergent plant species.
Breaking the Surface
Terrestrials are true land plants that inhabit dryish environments. Emergents are subaquatic plants that live (i.e. root) in water but send the majority of their leaves and stems above the water surface. While some true aquatic plants bear flowers that slightly breach the water surface, they otherwise must live entirely underwater.
The all-too-common retail merchandising of nonaquatic plants (sometimes slickly labeled as “decorative” varieties) alongside true aquatic plants might be taken by some to mean that they can survive and grow completely underwater in aquaria. Even so, these types simply cannot tolerate a subsurface existence for long; some species might survive for months submerged, while others pretty much die immediately.
Do note that most of these nonaquatic plants are extremely easy to keep in an appropriately constructed paludarium (i.e. riparium) or wet terrarium. In actual fact, many such species may be kept “in” aquaria if grown under aquaponic conditions—that is, if they are positioned in a way that allows only the lower parts of the plant to remain submerged.
For example, some small emergents or even terrestrials may grow well from fish tank accessories like the cartridge chamber of a hang-on-the-back filter. Additionally, quite a few cold-hardy varieties may be kept outdoors as marginals in small ponds or container gardens.
Here, we identify and discuss six nonaquatic plant species that may be found in the aquarium trade but, nevertheless, should not be used in the conventional planted tank.
Variegated Japanese Rush (Acorus gramineus)
This is a rather tall (up to 14 inches), grassy plant with slender but somewhat stiffened, whip-like blades. Derived from East Asian stock, this attractive cultivar has distinctive green and yellow stripes that run along its narrow leaves.
It forms thickened root masses that are said to have an ability to draw nutrients directly from the surrounding water. If at least half of the leaf length is above water level, it will readily propagate laterally through new shoots near the roots. It has a wide temperature tolerance (50-79° F) but prefers the cooler end of its range when underwater.
Though it is exceptionally hardy, this rush will decline and die within a year when kept submerged.
Caladium (Caladium bicolor)
If this plant looks a little familiar, it is likely because you have seen it many times before in gardens and plant nurseries. Its flashy, heart-shaped leaves are available in a variety of colors. The length of its stems can be controlled by tightly containing its root mass.
Although it is indeed a true terrestrial plant, it gets by with its roots dipped in warm (72-82° F) water. However, when planted completely underwater, it surely will be dead within a couple of months or days.
Striped Dragon Plant (Dracaena sanderiana)
This nonaquatic plant is easily identified by its thick, tough, lanceolate leaves that frequently have white or yellowish edging.
It can grow with its roots submerged but will die within a few months if kept completely underwater. It is an otherwise resilient species that will live long and reach a relatively large size (perhaps 20 inches tall) when brightly illuminated and grown in a warm (72-82° F) environment.
Crimson Ivy (Hemigraphus colorata)
The rough edges, crinkled texture and rich green (upperside) and purple (underside) coloration make the foliage of this species striking and unmistakable. This Indonesian native requires bright light and warm air and water conditions (72-82° F).
Under appropriate conditions, it reaches a height of 8 inches and can be easily propagated from cuttings.
Pretty as it is, it has absolutely no place in the aquarium. While some have reportedly kept it alive while submerged for as long as a year, most keepers find that it tends to die rapidly in aquaria.
Fountain Plant (Ophiopogon japanicus)
So-named for the gushing appearance of its foliage, the fountain plant commonly appears as an aquarium species. Its long, thin leaves may exhibit attractive white edging and striping.
It is highly adaptable and may subsist for many months completely underwater but should quickly be removed to a drier environment if leaves start to die. The fountain plant is best used as a marginal in a warm to slightly cool (64-79° F) environment. Depending upon the variety, it can grow to anywhere between a few inches to well over a foot in height.
Stardust Ivy (Syngonium podophyllum)
The stardust ivy is available in many color varieties with white veining, spotting or frosting. It can reach heights of about a foot but is usually a bit shorter.
This popular and widely available climbing houseplant is normally grown completely out of water. Stardust ivy will die almost immediately if its leaves are flooded. On the other hand, it can live and grow partially submerged with its long roots trailing into the water.
Some hobbyists plant small cuttings in the rockwork of paludaria and terraria with great success. So long as its leaves and stems are allowed to breathe, this plant is undemanding and will thrive under a variety of light conditions.
Maintaining Aquaria With Plants
There are really just few big concerns when operating a planted fish aquarium. Like all plants, plants for an aquarium need a fertilizer (such as API Leaf Zone freshwater aquarium plant fertilizer or Aqueon freshwater plant food) and a source of carbon dioxide (such as API CO2 booster) to grow. Vitamin and mineral supplements (such as Fluval plant micro nutrients) can help to improve health and promote growth and reproduction.
Aquarium Plant-Buyers Beware
One should not be discouraged from keeping nonaquatics such as the above-described species. A host of highly desirable ornamental terrestrials and emergents ranging from mosses to trees can be successfully cultivated if kept in the right type of environment.
To the point, a clearer distinction between aquatic and nonaquatic plants is certainly overdue in the marketplace. Until such improvements are made, aquarists would be wise to fully research any prospective plant species before making a purchase.