Anubias barteri var. nana is a slow-growing plant used in freshwater aquariums. Its dark green, sturdy leaves make it a favorite for aquascaping, typically attached to driftwood or rocks. Anubias nana is an amphibious plant that successfully grows in an emersed state, meaning its leaves are exposed to the air. This ability to transition between submerged and above-water environments makes it a versatile choice for paludariums and high-humidity terrariums.
Adaptation to Dual Environments
The plant’s capacity for emersed growth is rooted in its natural history and evolutionary biology. Anubias nana originates from the fast-flowing rivers and streams of West Africa. In its native habitat, it lives along the banks of these waterways, where water levels fluctuate significantly with the seasons. This makes the species a rheophyte, adapted to withstand strong currents and periods of frequent flooding. This natural cycle has equipped the plant to survive and thrive in both conditions.
Requirements for Successful Emersed Growth
Successfully transitioning Anubias nana to grow out of water relies on replicating the high-humidity conditions of its native rainforest environment. The most important factor is maintaining atmospheric moisture levels, ideally in the range of 70% to 100%. Without this high humidity, the leaves will quickly dry out and wither. The plant should be kept in an enclosed system, such as a terrarium or paludarium, to trap moisture and prevent desiccation.
While the leaves need air, the roots require constant moisture, which can be provided by a non-aquatic substrate like porous potting mix, sphagnum moss, or inert materials like lava rock. The thick, creeping stem, known as the rhizome, must remain exposed to the air and not be buried in any substrate. Burying the rhizome is a common mistake that causes it to rot and the plant to die.
The roots should be allowed to grow down into the moist material to draw nutrients and water. Lighting requirements are moderate, favoring indirect or filtered light, as intense, direct light can easily scorch the leaves in an air environment. Regular misting can help maintain the necessary humidity levels within the enclosure.
Physical Changes When Grown Out of Water
When Anubias nana successfully transitions from a submerged environment to an emersed one, it exhibits distinct morphological changes. The leaves that grow in the air become noticeably thicker and more leathery than their underwater counterparts. This change is a physical adaptation to reduce water loss. The leaves also typically display a darker, more intense shade of green when grown emersed. While the plant is known for its slow growth rate, a positive outcome of emersed cultivation is the increased likelihood of flowering. Anubias nana produces a calla-lily-like bloom, which is rarely observed when the plant is kept fully submerged.