AQUATIC HORTICULTURE		BY KAREN RANDALL

Creating a Lush Lawn In Your Aquarium

KAREN RANDALL

Lilaeopsis is an excellent ground cover choice for a tank with adequate lighting (i.e., 3 watts or more per gallon).

One component of aquascaping that has not often been seen in American tanks in the past is the extensive use of small foreground plants. Since Takashi Amano’ Nature Aquarium World series (T.F.H. Publications) has become available, I am often asked which plants are appropriate, and how to get a “lawn” going.

I think there are several reasons for the lack of use of foreground plants up to this point. Many Americans use a substrate that is too large for the roots of small, delicate foreground plants. Second, many aquarists still keep large “plecos” in their tanks that rip these plants out just by their vigorous movements along the bottom. Also, few of these plants are available in the average pet store, and those that are tend to be expensive. Finally, creating a lush fully planted foreground is a long-term project, requiring much patience, a quality that we Americans often lack!

I am glad that the Amano books have popularized the use of foreground plantings. One look at a tank like this and you know that it is an established tank. The aquarist has allowed it to develop slowly, and painstakingly, often over a period of several years.

Let’s take a look at some of the foreground or “ground cover” plants that are available, and how best to use them. There are plants in this category suitable for most any situation!

Common Foreground Plants

One of the most commonly available foreground plants is the pygmy chain sword (Echinodorus tenellus). There are several varieties and/or subspecies of E. tenellus, including one that turns a nice rusty red color under bright light. All forms are quite variable in leaf size, shape and color depending on conditions, so it is difficult to tell them apart in the aquarium unless they can be grown side by side.

With adequate lighting and a fine substrate, pygmy chain sword will quickly cover the foreground of your tank. It reproduces by runner, and will need to be thinned from time to time by carefully cutting the runners and pulling out the excess growth. If this is not done, you will start to see a number of transparent dying leaves from overcrowding. E. tenellus is a heavy root feeder and needs a constant iron source, so you will probably need to use a liquid trace element supplement, as well as laterite, soil and/or plant food tablets in the substrate.

Similar in look and requirements, but just a little larger, are the chaining swords, E. quadricostatus, and E. latifolius. Neither of these is as common as E. tenellus, but they are available if you look.

Another fast-growing, readily available foreground plant is dwarf sag (Sagittaria subulata var. pusilla). This North American native tops out at 2 to 6 inches (5 to 15 centimeters) and will also spread rapidly by runners in good light. This is probably one of the least expensive “lawn”-type plants available.

Lilaeopsis braziliensis is fairly available in pet shops under the common name “micro sword.” This is one of my favorite ground covers, as long as there’s good, strong light in the tank. Remove it from its pot and plant in a fine, enriched substrate. Before long you will see it begin to send out runners. While this tiny plant grows fairly quickly in good conditions, it is so small that it can take a while to spread into a substantial lawn. Still, once it gets going, it makes a dense, short light-green cover. Lilaeopsis is a good option for the planted discus tank. It grows even more vigorously in a warm tank as long as there are adequate amounts of light and CO₂.

Ever since the Amano books have been released in English there has been an upsurge of interest in two particular ground cover-type plants. The first of these is Glossostigma elatinoides. This little runner plant with the tiny spoon-shaped leaves is featured in many of Mr. Amano’s tanks. With its sparkling green color and lovely texture it’s not surprising that a Glossostigma lawn has become the goal of so many Nature Aquarium aficionados.

My experience with this plant has been that it does not appreciate hard water, needs bright light to remain horizontal, requires lots of CO₂ and must have a nutritious, fine-grained substrate. I was unsuccessful with this plant until I placed it in a tank with a soil-based substrate. Now I have a fine lawn of it established. Like Lilaeopsis, this plant can be very trying if conditions are not to its liking, but spreads rapidly when “happy.”

KAREN RANDALL

Water wisteria (Hygrophila difformis) is an easy, quick ground cover. Lay the stems horizontally on the substrate and anchor them with gravel or small stones. They will grow into a thick carpet, but need rigorous trimming to remain short.

Planting Glossostigma can be a real challenge as well. For those who are lucky enough to live in countries where Tropica potted plants are sold, the mat of Glossostigma can be left imbedded in the top of the rock wool it comes in. If it is planted with some of the rock wool attached, it will stay down until it is able to spread out into the surrounding substrate.

For those of us in the U.S. who do not have access to Tropica plants, Glossostigma is available commercially, but it is usually sold in its vertical growth form rather than horizontal. I have found that the only way I can get it to grow horizontally and at the same time keep it down in the substrate long enough for it to take hold is to cut it into pieces no larger than two or three nodes long and tediously plant it, piece by piece, using tweezers — a real chore, but with results well worth the effort!

The other plant that is often used as a ground cover in Amano’s tanks is Riccia. For those who are used to seeing this fluffy little plant floating on the surface, it may be hard to imagine it lying prone on the bottom of the tank. But, with a little effort and judicious regular pruning, it can be accomplished. Anyone who has seen the jewel-like mounds of Riccia covered with oxygen bubbles pictured in Amano’s books will want to give it a try.

Let me mention that not all Riccia work equally well, and the different types can be hard to tell apart. The type that Amano uses is slightly darker in color than the kind we usually see in the aquarium hobby in the U.S. A good-size clump of this variety of Riccia will settle to the bottom on its own, whereas ours would immediately float to the surface if left to its own devices. There are some native U.S. varieties that have a tendency to stay submerged in very shallow, brightly lit conditions.

Mr. Amano suggests using monofilament line to tie Riccia onto stones to keep it where you want it. Claus Christensen from Tropica has a different solution. He suggests buying fine mesh hair nets at the pharmacy. These can be cut in half and used to attach two clumps of Riccia to their stones just by wrapping the nets around them. Whichever method you choose, the Riccia will soon grow up through its constraints and hide them.

Riccia is not a no-maintenance ground cover. It must be trimmed close regularly with sharp scissors. Otherwise, the inside areas will die from lack of light and the newer growth on the outside will lift off and float away.

For a very fast answer to the problem of foreground planting, water wisteria (Hygrophila difformis) works very well. To get it started growing horizontally rather than vertically, simply lie the stems flat on the substrate surface and pin them down with small stones. The roots will grow down from each leaf node, while the plant will branch upward from the same spot. If there is a problem with this hardy plant, it’s that it grows so fast under good conditions that it must be pruned almost daily to keep it short enough to be used in this manner.

Ground Covers for the Low Light Tank

What if you don’t have much light on your tank? There are still a number of good choices for those who have low to moderate light levels, although you will have to wait longer for the plants to fill in. A number of Cryptocorynes stay very low, and several of them actually grow faster than you might guess. The biggest problem with using crypts as ground cover is that they are usually fairly expensive on a per-plant basis, so you may need more patience to achieve the look you want.

Some species that are useful in this application are Cryptocoryne x willisii, C. walkeri and C. parva. For a contrasting color, both C. bullosa and C. petchii are reddish, and also stay quite small. My personal favorite is Cryptocoryne affinis, which is a rich pine green with an attractive lighter vein pattern on the top and bright wine red below. Look around for other species as well — there are a number that stay small.

While not exactly a “lawn-like” plant, one of the best foreground plants for the low-light tank is Anubias barteri var. nana. This cast-iron plant has attractive, heart-shaped, bright-green leaves. It grows to between 4 to 6 inches (10 to 15 centimeters) in height. With time and good care it will form dense clumps that can be divided and spread across the foreground to create areas of interest. If conditions are to its liking, it will increase its decorative value by producing long-lived Calla lily-shaped white flowers.

One of the easiest low-light ground covers is Java moss (Vesicularia dubyana). Use a number of small, rough-surfaced stones, and attach Java moss to them by winding monofilament fishing line around them. Or, you can use the hair net trick with this plant. The stones can be dropped on the bottom of the tank in any configuration you choose to create islands of color or a solid, dense dark green carpet. Java moss, like Riccia, will require periodic trimming to prevent it from becoming dense enough that the inner layer dies off.

If you’d rather attach your Java moss to a piece of driftwood, you can either use fishing line or actually staple the moss to the wood with a staple gun. Within a few days the staples will have rusted and will no longer be visible. Fontinalis antipyretica can be used exactly like Java moss in coolwater tanks.

Once your eye becomes accustomed to a fully planted tank, the bare gravel at the front of the average tank will start to look naked and unfinished. Don’t miss this opportunity to work with some of the lovely little plants available for aquarium use.