Characteristics of the plant, the rules for growing azollas in the open air and at home, recommendations for reproduction, difficulties encountered in leaving, facts to note, types. Azolla, called Azolla in Latin, is a member of the genus of fern plants classified in the Salviniaceae family. In this genus, there are up to seed varieties. The plant is found naturally in the United States and continental South America, where it lives in water bodies. It is not uncommon for this representative of the flora in the English and Irish lands, it can be found in Morocco, the Hawaiian Islands and New Zealand, on the Australian and African continents, in Japan and China. That is, the distribution sites cover tropical regions and extend to temperate zones. Some of the species of this green inhabitant of the planet have such a rapid growth rate that they have been recognized as an ecological disaster.
| Family name | Salviniaceae |
| Life cycle | Annual |
| Growth features | Waterfowl |
| Reproduction | Seed (spores) and vegetative (cuttings) |
| Landing period in open ground | Cuttings, planted in spring or summer |
| Substrate | Any nutritious silty soil |
| Illumination | Open area with bright lighting |
| Water | Weak acidity |
| Moisture indicators | Should always be high |
| Special Requirements | Some difficulties |
| Plant height | 2.5cm |
| Type of flowers, inflorescences | Does not bloom |
| Decorative time | Spring-summer |
| Place of application | Aquariums, artificial reservoirs |
| USDA zone | 3, 4, 5 |
If compared with the height parameters of ordinary fern representatives, then this annual is very small and has such external differences, then uninformed people may mistake it for duckweed or some types of mosses. Sitting on the surface of the water, Azolla can cover its surface, like a dense carpet, which outlines resemble moss lace. Plant height does not exceed 2.5 cm. Azolla stems are horizontal and floatable, with abundant branching. They can be up to 25 cm in length. Their surface is covered with small scales. Leaves of very tiny sizes grow on the shoots. Their shape is somewhat similar to carrot or forest fern foliage, as they gather in feather-shaped bunches. The sheet plate consists of two parts. One of them (the lower one) is completely under the surface of the water, and the upper one floats on the surface.
The lower floating segment has a special blade formation, which is directed downward, and it is in it that the blue alga (Anabaena azollae) "lives", which has the ability to absorb both nitrogen and oxygen. With its outlines, the underwater part resembles a root, and the leaf itself is feathery. In the winter months, it falls asleep, but in the spring-summer period it begins to develop and continue its growth. Despite the fact that the azolla is not devoid of a well-developed root system, it has also adapted to assimilate nutrients with every millimeter of the surface of its small leaf. The color of the foliage varies depending on the variety, from blue to deep green.
With the arrival of autumn, the shoots of the plant begin to rot, while the spores from the leaves sink to the bottom of the reservoir, waiting out the cold season there. And with the arrival of spring heat, Azolla is reborn from those fallen spore "deposits".
Many gardeners are familiar with only one representative of the Azolla - fern (Azolla filiculoides), and often cultivate it in open artificial reservoirs or conservatories.
Azolla growing rules - caring for the plant outdoors and at home
- Lighting. Most species of this floating fern prefer good light levels for daily durations exceeding 12 hours. The biggest sunshine lover is the Azolla nilotica species. If wintering is not carried out, then artificial lighting is used. In this case, they use LB fluorescent lamps (giving white light) or incandescent lamps. In terms of power, such lamps are selected so that their parameters are in the range of 2–2, 5 W per area of 1 square decimeter of the water surface. If such requirements are not met, then the plant begins to die off, which happens in the natural environment with the onset of autumn.
- Choosing a landing site. The plant does not like strong currents and prefers to grow in nature in shade with standing water or with very slow movement of it. When landing in an artificial reservoir in the garden or in the country, it is better to place the azolla away from man-made fountains or streams. If it is decided to cultivate such a representative of the Salvinievs in aquarium conditions, then the container is placed in such a way that the lighting is diffused and not too bright.
- Content temperature. It is clear that we will talk here about growing in aquariums, since it will not be possible to maintain the correct heat indicators under natural conditions. For Azolla, a temperature range of 20-28 degrees is best. The latter is appropriate for a tropical aquarium, while the former is suitable for outdoor use. When the wintering period begins in the fall, then at home it is necessary to lower the thermometer column to an indicator of 12 units and transfer the plant to the moss. But if such a period of rest has not yet begun, and the temperature has dropped below 16 degrees, growth stops and the beginning of decay is noticed.
- Indicators of water acidity when growing azolla at home, it should be at least pH 7, that is, its reaction is kept neutral or slightly acidic. Also, do not forget about the salt content of the liquid - it should be low, that is, the water used for Azolla is soft with a hardness of no more than 100.
- Fertilizers when grown in artificial reservoirs, it is not recommended to use it, since the drugs can provoke the growth of algae that inhibit this waterfowl fern.
- General information on care. Some varieties (for example, Azolla caroliniana) can be placed on moistened sphagnum moss for the winter period or powder moss can be used. Some aquarists transfer this water fern to a glass jar filled with soil from a pond, rich in silt and a little water. When March or early April comes around, the leftovers are put back into the aquarium. But even if these measures are not taken, then when grown on a country pond, the plant will begin to rot in autumn days. His spores fall to the bottom of the reservoir, but after the onset of the warm season, they successfully resume.
When grown at home, it is recommended to keep Azolla in a tropical aquarium with slightly acidic and soft water, since only these conditions will facilitate its reproduction. If they are not going to spend the winter, then the plant can be preserved in its original form at high water temperatures and a fairly bright level of illumination.
Azolla breeding tips
To get a new plant with floating stems, division of its overgrown bush is carried out or spores are sown.
For this division, the time is selected in the summer months. It is necessary to break off the side branches of the azolla and plant them in a nutrient substrate in the same reservoir (aquarium or pond). In this case, you should not carry out any feeding or use a special soil, since this representative of ferns will begin to form roots in a couple of days.
If it is decided to propagate by spores, then it should be noted that this method is of little use when growing in an aquarium for Azolla. This is due to the fact that it is necessary to frequently change the water in the container and the spores will be removed with the old liquid. If the plant is in a garden lake or pond, then when the growing season comes to an end, the leaf plates will begin to die off and fall to the bottom. The reservoir in winter is covered with ice, and spores are perfectly preserved at its bottom. When the water warms up with the onset of warmth, then from the numerous spores remaining in the foliage that has fallen to the bottom, new young plants will begin to renew.
Difficulties in growing Azolla
It is important to remember that if the climate is favorable, this fern-like floating green mat can grow very aggressively. You can fight it only by removing part of the colony. So in the southern regions, where azolla often becomes a real ecological problem and this property is well known.
This plant does not like flow either, since it is used to living in stagnant water in nature. Therefore, when growing in a garden reservoir, this fact is also taken into account.
Facts to note about Azolla, fern photo
When planting Azolla in a pond that is in a garden or summer cottage, it is better to place the plant next to some kind of boulder or fence, for which it will catch on with its shoots and will calmly grow there.
Colonies of this floating fern are usually used as fertilizer for rice. Usually, parts of the azolla or its spores are launched into the reservoirs where rice is grown, and after a while a green rug will form on the water surface. All this is due to the fact that this representative of the aquatic flora actively accumulates nitrogen in its parts, which is so required for rice plantations. Often, in order to use azolla as fertilizer, its colonies are directly grown in special creeks, and then, when the green "mat" grows well, it is laid out in the fields on a substrate and buried by plowing into the soil.
These feathery leaves and stems are used as food for poultry such as geese, chickens or ducks. All because of the increased nutritional value of the plant. If Azolla is grown in an aquarium filled with different animals, then its root system becomes a refuge for fry or shrimp. Unlike other algae, this waterfowl fern is not interesting for fish as food. But growing, with its coating, azolla can protect those aquatic plants that will die from the direct rays of the sun.
Thanks to the symbiosis of this floating salviniaceae with blue-green algae, the plant accumulates nitrogenous compounds in itself, and the alga helps to fix them.
Azolla species
- Fern Azolla (Azolla filiculoides). Well known to aquarists who use the variety to decorate aquariums or artificial home ponds. The stem is very branched. The size of the leaves of this floating fern plant reaches only 1 mm. The shape of the leaves is elongated with a pointed upper segment. The leaves are located mainly on the stem in its upper part in two rows. The upper part of the leaf is slightly larger than the lower one. The color of the leaf plates can vary from bright green to burgundy. But at the very beginning, pink shades are mixed into the color of the foliage. If the plant is in direct sunlight, then its leaves become brick-colored. In aquariums, it acts as a "house" for shrimp or fish fry. It also helps oxygenate the water in tanks for other inhabitants of the aquarium world or garden pond.
- Azolla caroliniana (Azolla caroliniana), called the water fern, it is also used in home aquariums. In natural conditions, it is found on both American continents. After the plant has undergone acclimatization in European lands, they try, although not very successfully to grow it in our climate, it is found in two Asian regions. The leaves can form floating green islands on the surface of the water. The foliage looks like small scales that grow on the shoots in the opposite direction. During the period of vegetation activity, their color is bright green, but by autumn they acquire a brown color. There is a discolored border along the edge. The size of the stem, which grows in the horizontal plane, can reach 2.5 cm in length. It has a very high growth rate and can cover the entire surface of the aquarium with its foliage in a short time, therefore it is recommended to periodically remove part of the colony. However, the view is capricious and requires careful maintenance. Because of this, the plant is a rarity among aquarium lovers. It is also characterized by a pronounced seasonal nature of growth - dormancy in winter.
- Azolla nilotica (Azolla nilotica). By the specific name, it becomes clear that the plant is native to the Nile banks and is distributed along the entire length of the river. The size of this species is much larger than others. The length of the stem is close to 1.5–6 cm, but there are specimens with shoots stretching up to 35 cm in length. Root processes grow in a bundle-like manner. Their size reaches 1.5 cm (occasionally 15 cm). The stem grows horizontally, it is devoid of leaves, but its surface is covered with small scaly formations. They are arranged in the form of tiles. The branches of the variety grow oppositely, in thickness they can vary within 1–1, 5 mm. Dicotyledonous leaves are painted in greenish or blue-green color. There is a wide discolored edge on the hem. It is a rather rare species, but due to its size it is interesting for aquarists. However, since the plant needs a lot of light and high heat indices, it is difficult to grow Azolla Nile indoors. Shows its growth well in the spring-summer period in greenhouses or shallow aquariums, where it is located above the muddy ground.
- Small-leaved azolla (Azolla microphylla). It is mainly found in nature in the Galapagos Islands. Possesses a rich dark emerald color of scaly foliage. The difference in this variety is the presence of a rudimentary ring. Each of the microsporangia contains 64 microscopic spores. They combine into several groups surrounded by a substance that resembles foam. This substance owes its appearance to plasma, which diffuses from the layer of cells lining the sporangia - tepatum. Uplants of the Salviniaceae family are called masses.
- Azolla Mexican (Azolla mexicana). Distributed in South America. Differs from other varieties in the color of scaly leaves. Mainly steel tint with a green tint prevails. On the surface of the masses, the development of clinging outgrowths occurs.
- Azolla pinnata (Azolla pinnata). Osthenia is widespread where it is warm and dies from any cold snap. Prefers to "settle" in shallow ponds or rivers, where there is no fast flow. It is mainly found in the Australian and African continents, on the island of Madagascar and in New Guinea. The stem is highly branched, the color of the leaves is dark red. The first mentions date back to 1810. It has the property of saturating not only water, but also the soil with nitrogen. In aquariums, this species practically does not grow; it is cultivated in shallow garden ponds. The root system is feathery in outline, the foliage is feathery. The size of the plant does not exceed 2 cm. The entire length of the stem is the basis for the lateral shoots of the leaf plates. Their size decreases as they approach the top of the stem. The size of the leaves is 2 mm. Their shape is pointed or there is a rounded top. The upper segment of the leaf has a fleecy coating that makes it velvety to the touch.
