Subclass Rosidae ( Rosidae )
Order Myrtales ( Myrtales )
Family Lythraceae ( Lythraceae )
Genus Rotala — Rotala.
They originate from Southeast Asia. There are approximately 10 varieties of rotalas. An aquarium planted exclusively with rotalas looks very spectacular. All rotalas love soft water. In tap water, without carbon dioxide supplementation, rotalas degrade. You should plant Rotala in small groups and not too sparsely. Rotalas are very small in diameter, single plants do not look good; they need to be planted in groups of ten stems or more, in bunches of 2 cuttings spaced 3 cm apart. After the first trimming of the tips, they will begin to branch and acquire a lusher appearance. These plants can be planted in the background and midground, optionally forming terraces through trimming.
These plants absolutely cannot tolerate a lack of light. If Rotala species grow slowly or do not develop at all, the cause must definitely be sought in poor lighting or insufficient CO2. CO2 should always be present in concentrations not dropping below 20 ppm. Lighting should be at least 0.5 W/l with 6500K lamps, which enhances the red hue of the leaves. Constantly maintain the plants using balanced fertilizers containing mandatory iron and other microelements, without which it is impossible to achieve good results. The triad of elements — light, nutrients, and CO2 — is mandatory when growing this plant. Water temperature should be between 25 and 27°C.
Pruning is one of the most important aspects of growing Rotala. These are fast-growing plants, and pruning after planting should be quite radical, about half the stem height. The goal of the first pruning is to stimulate the plant to bush out to create a group bush structure. After the plants reach the water surface, a second pruning is performed, less severe, depending on the chosen design. Cut just above the node, moving down from the back bushes to the front ones so that the back bushes are slightly higher than the front ones.
You should propagate rotalas like all stem plants: separate and plant the top. The upper part will grow roots, and growth points will awaken in the lower part. For successful division, each part must be at least ten centimeters. Mainly cultivated in aquariums: Rotala rotundifolia, Rotala macrandra, Rotala indica, Rotala wallichii, Rotala sp. “Nanjenshan”, Rotala sp. “Green”.
Rotala sp. “Bangladesh” — Leaves are thin and narrow, green. The top of the plant becomes reddish under bright light. Intense lighting and a sufficiently high CO2 level are required. Under proper conditions, it grows quite quickly.
Rotala sp. “Green” – Warm water will promote its growth, this species is not demanding regarding pH or water hardness. CO2 is necessary for faster growth. Pinching the tip will lead to the formation of lateral shoots and lushness of the plant. Propagated by cuttings.
Rotala sp. “Nanjenshan” — Grows well in soft water rich in carbon dioxide. Strong light and iron supplementation are also important and contribute to the appearance of a reddish color on the stem tip. The coloration of Rotala directly depends on lighting intensity. Under normal conditions it is green, but under very bright light, it acquires a noble golden-brown color. Moreover, it changes color very sharply. Even within the same aquarium at different depths, it can be of different colors. To achieve a more compact bush, trimming is necessary, which will produce abundant side shoots.
Rotala sp. “Vietnam” — Very similar to Rotala wallichii. Grows vertically and produces many side shoots. Moderate lighting will yield mostly green plants with red stems, while intense lighting can produce a pleasant golden hue. CO2 additions are necessary for good results. Propagated by cuttings.
Giant Red Rotala, Macrandra — Rotala macrandra.
“1” (Eng. Giant Red Rotala, Macrandra). Water bodies of coastal regions of China and India. An unusually beautiful, but unfortunately, very fussy aquarium plant, so much so that it can grow well in far from every aquarium. Reaches a size of 25-55 cm. Width 2-7 cm. Stems are long, poorly branched; the plant branches intensively after pinching or reaching the water surface.
The leaves are ovate with wavy edges and reach sizes up to 5 cm in length and 4 cm in width. Leaves grow in pairs on both sides of the stem, symmetrically located relative to each other. The underside of the leaf is colored purple, while the upper side varies from red to green. Leaf color depends on lighting levels.
There are several varieties of Rotala macrandra:
— Macrandra green – Rotala macrandra “green”. Submerged leaves are decussate, sessile, very narrow elliptic, up to 1.7 cm long, 1.3 cm wide, light green.
— Narrow Leaf Rotala – Rotala macrandra “Narrow Leaf”. This form has a narrower leaf compared to regular macrandra. It grows upward, forming many side shoots on the way to the surface. If allowed to grow along the water surface, it will produce them at every node. Less sensitive to growing conditions; however, lighting must be of medium intensity, otherwise the lower part of the stem will turn black. With an iron deficiency, it begins to pale.
— Green Narrow Leaf Rotala – Rotala macrandra “Green Narrow Leaf”;
— Macrandra florida – Rotala macrandra florida;
— Dwarf Macrandra – Rotala macrandra minima;
— Mini Type II Rotala – Rotala macrandra “Mini Type II”;
— Variegated Rotala – Rotala macrandra “Variegated”. Has a characteristic pattern formed by contrastingly colored veins.
“2” Giant Red Rotala is one of the most demanding tropical aquatic plants. It grows in a tropical aquarium with high water temperatures (27-30°C). At temperatures below recommended, even at 25°C, growth practically stops, old leaves quickly disintegrate, and young leaves become smaller. Water hardness for keeping is recommended within 2-6°, although Rotala tolerates harder water quite well. Active water reaction should be slightly acidic or neutral with pH 5.5-7.0. Water must be very clean. Regular water changes and the addition of peat extract are needed. It tolerates the presence of many chemical substances in water very poorly, particularly sodium ions, so additions of table salt and baking soda are entirely undesirable. The plant loves water circulation. CO2 fertilization is also recommended.
For keeping, fairly bright lighting is required, under which the leaves acquire such an attractive red color. The light source should be placed directly above the plant, with a predominance of the red-orange light spectrum. Day length should be at least 12 hours, but at the same time, Rotala must be protected from algae. Blue-green algae are especially dangerous for it. It is difficult to achieve lighting such that the lower leaves are as beautiful as the upper ones. If the leaf length does not exceed 2 cm, this is a sure sign of a poor environment in the aquarium.
“4” Rhizome is creeping with a large number of leaf buds. Root system is very poorly developed. Additional rootlets form on stems creeping near the water surface. Despite this, the plant must be planted in the substrate. The substrate should be fairly nutrient-rich, but not too silted; a few lumps of clay and peat should be added under the plant’s roots. Considering the delicate structure of the root system, the substrate should use not very fine river sand, and the layer thickness should be no more than 3 cm.
The red color of Rotala, besides lighting, also depends on the level of iron it receives. Mineral supplementation should be done very carefully, as the plant reacts poorly to the slightest excess of salts in the water. The concentration of mineral fertilizers for Rotala should be 2-3 times less than recommended for other plants. In addition, it is better to apply fertilizers in portions over several times during the week.
“5” Looking as if lacquered, oval purple leaves make this red-leaf variety of Rotala one of the most beautiful among aquarium plants, looking great against the background of green leaves of other plants in the aquarium. Rotala must be planted as close to the light source as possible, in the brightest spot of the aquarium. The color of Rotala depends on the level and intensity of lighting in the aquarium. A sign of good lighting is the color of its leaves, which turn red. With a lack of light, leaf color becomes pale pink. With plenty of light, it acquires a more saturated red color. When reducing the lighting level in the aquarium, remember that the less light there is, the slower Rotala will develop, and it may not develop at all.
Planting in a bunch is undesirable; in this case, the lower leaves lack light and turn brown. It grows by forming dense thickets from its branches, which look astonishing in any aquarium. Left floating, Rotala grows very slowly and gradually shrinks in size. It looks best in large groups, approximately 20 stems per 50 cm, but they should not be too dense, otherwise side shoots will shade the lower leaves. If your aquarium has enough lighting for it, you will prune Rotala quite often. If you notice that Rotala is dropping leaves at the base of the stem in your aquarium, you should cut the tops to add young plants to the “thickets,” and the remaining empty part of the stem will eventually sprout new leaves, or more likely, new branches.
For active development and for the plant to acquire an attractive red color, it needs plenty of light, CO2 fertilization, a sufficient amount of microelements, especially ferrous iron, and the absence of fish in the aquarium that like to eat aquarium plants. It is very sensitive to finger touches, and during transplantation, it should be in the air as little as possible. The plant’s leaves are very delicate and dry out quickly in air. Sensitive to damage during transportation. When buying, make sure that leaves and stems are not damaged. Otherwise, the plant will take a very long time to take root and acclimatize at the new planting site. During transportation, ensure it is always moist, because if the surface of this plant begins to dry, it will die very soon. When transplanting, old roots should be shortened.
In good conditions, it grows quickly. Does not tolerate the introduction of salt and baking soda into the water. Red-leaf Rotala, unfortunately, is so caprice and demanding in maintenance that far from every aquarist can create the necessary conditions. It is characterized by high sensitivity to any changes occurring in the aquarium, which is why it belongs to plants that are very difficult to keep. Sometimes an aquarium needs to be specially equipped to keep Rotala.
“6” Propagated by stem division. Cuttings should be 7-10 cm long, as shorter ones start growing very slowly. A cutting taken from the middle of the stem must have a formed side shoot. During all manipulations with the plant, handle it with extreme care; the plant should be in the air as little as possible during transplantation, and besides, touching it with fingers should preferably be minimized as well.
Identification: Macrandra Rotala — Rotala macrandra.
Wallich’s Rotala — Rotala wallichii.
“1” From swampy areas of Southeast Asia. A stem herbaceous plant reaching up to 40 cm in length, very similar to river myriophyllum, with a whorled arrangement of darker leaves. Narrow, delicate thread-like (up to 15 pieces) leaflets reach 1-1.5 cm in length, densely covering the brown stem, and under favorable conditions have an orange-pinkish tint in the upper part, with a light green color at the bottom. This plant is quite delicate, capricious, and demanding regarding keeping conditions.
“2” Suitable for keeping in a tropical aquarium at temperatures not lower than 22°C. Optimal water temperature is 24-26°C. Water should be soft, preferably with a total hardness of no more than 4°, and a slightly acidic reaction, pH 5.5-6.5. At hardness above 6°, growth almost stops. The plant cannot stand turbidity in the aquarium, therefore a high-performance water filter is required. Up to 20% of the water volume should be regularly replaced. CO2 supplementation is necessary.
Bright lighting with an intensity of about 0.7 W/l is required for Rotala. With a lack of light, it begins to stretch out, and its leaves lose their original coloration. However, bright natural lighting is unacceptable — algae can grow on the leaves. Day length should be at least 12 hours. Under unsatisfactory conditions, the leaflets lose their original light-pink color and turn an ordinary olive color. Usually, the plant dies quickly due to algae overgrowth. The aquarium plant does not tolerate any chemical additives and reacts to them painfully. Recommended nitrate level — no more than 10 mg/l. In addition, the delicate leaflets of Rotala can be eaten by algae-eating fish.
“4” The root system in Rotala is weakly developed and, like many other plants of this type, mainly performs the role of anchoring to the substrate. Therefore, when planting it in sandy substrate, it is necessary to press its roots with small stones. The plant receives its main nutrition from the leaves, so the nutritional properties of the substrate have little effect on Rotala’s development. Sand laid in a 2-3 cm layer should be used as a substrate. Wallich’s Rotala does not like gravel with a fraction greater than 4 mm.
“5” One of the most difficult aquarium plants. Recommended only for experienced hobbyists. Very demanding regarding keeping conditions, it reacts very quickly to the slightest fluctuations in the balance of aquarium water elements. Even during the day, its appearance changes, which apparently depends on pH and iron content. These two parameters are known to vary greatly throughout the day. Wallich’s Rotala is suitable for stocked aquariums with artificial carbon dioxide enrichment. This plant loves bright light very much. Under strong lighting, the finely dissected leaf in the upper part has a golden-reddish color, rich red-brown or crimson, and in the lower part — bright green. At lower temperatures or weak lighting, the plant stretches in length, becomes very small, and its leaves turn pale green; it may even die.
Grows up to 10-30 cm in height. An aquarium of any capacity suits it, but it grows best at a low water level, up to 30 cm. The plant is planted in the midground, in a group of 10 stems, but mandatory at a distance from other plants to ensure sufficient illumination. The greatest decorative effect is achieved if a large number of stems grow in the group. Under acceptable keeping conditions, it grows relatively fast, up to 20 cm per month. This Rotala tolerates trimming poorly. Therefore, it is better to cut it from the bottom and replant. Aquarium hygiene requires special attention since Rotala is very susceptible to colonization by parasitic algae. One must ensure that the plant’s leaves do not start becoming overgrown with algae.
“6” Propagated by cuttings, separation of basal shoots, or stem shoots.
Round-leaved Rotala, Indian Toothcup — Rotala indica, rotundifolia.
“1” Southeast Asia. An unpretentious plant, it has a round stem growing vertically upward from the rhizome base. On the stem, symmetrically opposite each other, are leaves of two forms: submerged — lanceolate, juicy-green, and emersed — rounded. On stems reaching 20-25 cm in the aquarium, delicate light-green elongated leaflets about 1 cm long sit in pairs. There are usually 2–3 leaflets in a whorl. One pair is at a short distance from another.
Usually in the lower part of the stem, the leaves are small or absent altogether. Higher up, as it approaches the water surface, the leaves become larger, juicily colored, pinkish underneath. New shoots mainly emerge from the rhizome. Shoots reaching the water surface continue to grow above it. There is a subspecies — Rotala indica “Green” — Green. — Rotala indica “Aurea” — Golden. Aquarists cultivate a closely related species — round-leaved Rotala (Rotala rotundifolia). The distance between leaves is slightly greater than in Indian Rotala. In the aquarium, it grows all year round.
“2” It is best to keep Rotala in a tropical aquarium at temperatures above 24°C. At lower temperatures, this plant, which develops slowly in water, practically stops growing. Water should be soft or moderately hard. It feels best in water with a total hardness of less than 6°, and if hardness exceeds 12°, it quickly dies. Active water reaction is preferred neutral or slightly acidic. In alkaline water, the plant develops unsatisfactorily. Cleanliness must be maintained in the aquarium, good water filtration, and up to 25% of the water volume regularly replaced. The appearance of turbidity in the water leads to a deterioration in the plant’s appearance and slows down its growth.
Lighting should be moderately bright. Especially well begins to develop the part of the plant located directly near the light source. The lower part of the plant, whose leaves are in the shade of the upper leaves, gradually becomes bare. Lighting is selected individually, taking into account that it tolerates moderate shading. With a lack of light, Rotala stretches out and looks weak and pale, leaf sizes decrease. With good lighting, the underside of the leaf turns red. Excessive lighting leads to the formation of algae disastrous for the plant. One can be guided by the coloration of young leaves, which under favorable conditions acquires a reddish tint. At pH 6.5-6.8, the inner part of the upper leaves has a purple color. Day length is about 12 hours.
“4” The root system is weakly developed. Rhizome is creeping, branched, with white adventitious roots and a large number of leaf buds. Substrate should preferably be fine-grained, consisting of rounded particles. When planting it in the substrate, it is desirable to ensure it holds well by weighing the plant down with stones. The plant does not need fertilizer supplementation. A plant grown in substrate has plenty of natural silt for nutrition. A floating plant, receiving nutrition only from water, develops slower. A plant taken from a greenhouse can be placed directly into the aquarium.
“5” Of all Rotala species, this plant is less sensitive to water parameters and easier to keep. The plant can be planted in the substrate — then it acquires a more spectacular look, or left floating in the water column. Individual branches of Rotala grown in water look unpretentious. However, a large bush looks very spectacular and combines well with broad-leaved plants. Round-leaved Rotala is placed closer to the side walls and in the background. It is advisable to allocate the brightest spot in the aquarium for the plant, as the lighting level determines the plant’s appearance.
It quickly forms side shoots, becoming a compact and dense plant, but at the same time, the lower leaves are shaded, this part of the stem becomes bare, and the leaves pale. It is recommended to regularly thin out the thickets of the aquarium plant, rejuvenating it by replacing old branches with young shoots. This Rotala is a typical “invader”: often the plant sends a horizontal stem along the bottom, from which roots grow first, followed by vertical stems. These horizontal stems must be regularly cut off, otherwise Rotala can “overrun” the entire aquarium. In good conditions, the plant grows very quickly throughout the year. Disadvantages: the plant grows too fast and creeps along the water surface, shading everything beneath it. Round-leaved Rotala is prone to algae overgrowth.
“6” Propagates well by cuttings, side and basal shoots. The side shoot is separated from the mother plant and replanted in the substrate, pressed down with a small stone. Under good lighting, the side shoot will quickly release roots and grow very rapidly. A plant from a greenhouse can be placed straight into the aquarium. In this case, after a short pause, its growth will continue, and shoots will form with elongated leaves characteristic of an underwater habitat.
Nuphar japonica, Japanese Spatterdock.
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