Bulb Plant Primer Part One
When someone mentions bulb plants it's natural to think of flowers or vegetables. However, there are many aquatic bulbs, and in this post we'll learn what's available to the planted tank enthusiast and how to keep them.
As with other aquatic plants, a good, nutrient rich substrate is vital to keeping bulb plants long term. Bulb plants store their nutrition in the bulb or corn and use it for growth. A good planted tank substrate provides the minerals (like iron and potassium) to keep the plant fed. Like all plants they prefer a warmed substrate. Low wattage cable heaters are available that pull nutrient rich warm water down to the roots, giving them circulation and can help eliminate dead spots.
Many do well in 2 watts per gallon of full spectrum light. All will do well in 4 wpg or even five, and some must have that bright light to thrive. Carbon Dioxide injection can be used, but some species grow spectacularly with or without it. Some are among the easiest plants to grow, some are among the most difficult aquatic plants to have success with. Thus, there's a bulb plant for nearly anyone.
Now some species
Aponogetons, from the African island of Madagascar and Southeast Asia, run the gamut from among the easiest plants to grow to among the most difficult to keep. Aponogetons' bulbs are long and cylindrical with two narrow ends. Leaves sprout from one or occasionally both ends. All of them keep to their natural rhythm of steady and in some species of explosive growth and look gorgeous for many months, then leaf production ceases, the plant may appear to die back as leaf production slows down and may stop. Old leaves may start to die. If conditions are good, new leaves will sprout and grow. In this Genus the rest period lasts month to six weeks, but nearly all of them insist on that rest period. Due to man-made hybridizing, the rest period isn't as severe as it once was, where the whole bulb was removed when the plant diminished, put in a jar with wet, cold sand and left in a cool dark place for six weeks, only returning it to the tank when growth started. Aponogetons were among the 'mystery bulbs' that were sold in a package near department store pet areas. A good number were Aponogeton species, though some were water lilies.
One of my personal favorite aquatic plants is A. ulvaceus of Madagascar. Twenty-inch long, almost 2 inch wide smooth, shiny, undulating bright green leaves, with greens, russets and golds in bright light, typify this plant. This gorgeous plant when happy grows like mad, shooting out leaf after leaf and becoming a dominant force in the aquarium. Each plant produces two flower spikes, but fertilization for seed production is only possible if there's another ulvaceus in the tank; use a soft brush to transfer pollen from one plant to another.
As with all Aponogetons, ulvaceus' corn should be laid on top of the gravel until growth ensues. Wait until several leaves and roots form before gently pushing the corn under the gravel.
On the other end as far as difficulty goes is a plant of almost mythical proportions; the Madagascar Lace Plant (A. madagascariensis). Some keepers have very little trouble with this plant, some give it up in despair. According to Innes (Exotic Aquarium Fishes, 15th Edition, 1953), the plant grows very well in the hard and alkaline waters of New England, but does just as well growing outdoors in half barrels of oak, which are of course acidic.
What makes this plant so popular is its leaves; they are skeletonized. Only visible are the veins; there is no leaf flesh between them. Those odd leaves reach up to 25 inches (usually much smaller) and puts up a fuzzy yellow flower when really happy.
There are geographical differences in the width of the leaf, depending on where the original wild parent plant came from. In some it is quite narrow, in others, reaching the width of an ulvaceus leaf.
Peat extracts, either in liquid form or granular in canister filters, is necessary with this plant. They prefer filtered light; it can be 4 watts per gallon but this plant needs to be shaded where the light is diffused. Most important is weekly water changes, up to 75 percent. It prefers water in the mid 70's, and it should be soft; less than 10 degrees of hardness.
The Madagascar Lace Plant, due to its difficulty, hasn't been hybridized, so the old-fashioned wait period must be ensured if an aquariast wishes to keep this plant for years (like all Aponogetons, they are long lived). The water should be slowly lowered over a week to 66 and held there for two months. When growth returns, the temperature should be slowly raised over a week to its normal temperature. Then you can move it back to the warm show tank and very, very carefully replant it.
A. madagascariensis's leaves must be kept free of algae and debris. Fish such as a troupe of Otocinclus should be employed to keep the leaves clear.
One who keeps the Madagascar Lace Plant successfully long term should be justly proud.
Strongly stemmed, hammered, medium green leaves typify A. boivinianus, another Madagascar species. Its bulb is truly bulb-shaped, with leaves coming out of the top. A lusty plant that grows surprisingly rapidly, boivinianus prefers space to grow; it doesn't do well in a heavily-planted tank. The character of the leaves - the hammered, spear -shaped look and the translucent green, makes this plant easy to ID. It prefers and does best in very bright light, and can flower and bear fruit in the aquarium. It commonly reaches 20 inches tall, and has no other special requirements other than a good substrate and bright light.
One of the most commonly available and most hybridized species is A. crispus of Sri Lanka (Ceylon). A smaller species, crispus has crinkled-edged, oblong lancelet leaves about a foot tall. Because its been crossed with several species of Aponogeton, the true crispus isn't easy to find as it once was. Only the flower, which it does occasionally appear in the aquarium, can reveal its true identity.
No matter. Other than good light (3 or 4 WPG is preferred) and a good substrate, crispus needs little else, and will produce many leaves rapidly when it settles in. A wait period isn't as needed as it once was, but the cool sand in a dark place when growth stops may improve its life span. I haven't given my plants a wait period, and they have grown perfectly for years in my tanks.
If the leaves grow taller and thinner and reach the top of the tank, the lighting is insufficient. Otherwise, crispus is one of the easiest of the Genus to grow.
From India and the Malay Peninsula comes A. undulatus. The species name gives a clue; the leaves undulate. They are middle green, spear shaped, and 10 inches tall, and are one of the few Aponogetons which is easy to propagate. A mature plant produces little miniatures of itself, complete with bulbs, around its rootstock. When established, they can be removed and replanted.
The leaves have odd translucent areas, and are not indicative of a problem. Like all Aponogetons, it likes temps in the mid-to upper 70's. Undulatus grows very well, and poses no problems for the grower. No rest period is needed. A lovely plant, undulatus is usually the plant hybridized with crispus, but is more common in its natural form.
One of the most beautiful of the bulb plants as well as one of the most difficult to grow is the Orchid Lily - Barclaya longifolia of Myamar, Thailand, Indochina and Eastern Africa.
Last edited by Dave66; 01-08-2008 at 08:08 AM.
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