Pogostemon helferiHOOK. F. 1982
Author: Adam Shappard
Native Distribution: Western Thailand, Burma, India
Aquarium Placement: Midground to foreground
Requirements: Soft to medium-hard water, plentiful nitrogen, phosphorous and potassium, ample micronutrients
Relatively new to the United States aquarium hobby, Pogostemon helferi has an unmistakable and unique appearance. With wavy leaf margins and compact bushy growth, it stands out not only in its genus but among all aquarium plants.
Often known by its common name downoi (“little star”), P. helferi is found at the edges of streams in Asia. During the wet season, it grows submerged and creates dense mats. In the dry season the plants are exposed, and in the emergent form the internodes will lengthen. Attractive but small (less than an inch) purple flowers will form on a terminal spike.
P. helferi is not particularly difficult to grow if its needs are met. Soft to medium-hard water with a nutritious substrate can be helpful, but available water column nutrients are required to reach the full potential of this species. Ample nitrogen will result in wider, darker green leaves, and along with higher lighting, encourage compact growth.
Other macronutrients such as phosphorous and potassium are necessary but not required in great amounts. Micronutrients should be abundant for the best results. If lighting is too dim, the internodes may lengthen and leaf shape will be less appealing. Additional CO2 injected into the water will aid in healthy growth and is recommended.
Propagation: The unusual appearance of P. helferi may seem to present a challenge, but it makes an attractive mid- to foreground plant in the appropriate layout. Irregularly shaped plantings of it in the midground with low-growing carpet plants like Hemianthus callitrichoides in the foreground works well. Carefully placed rocks will complement the layout without drawing too much attention from the plants. Growth rate is not particularly rapid, so it is possible to maintain a consistent appearance without frequent trimming. P. helferi is unlikely to reach the surface in all but the most shallow aquariums.
Notes: Sideshoots will develop as the plants mature, creating a bushy appearance. Roots will soon form on the sideshoots, and you can snip them off and replant to begin a new cluster. It is also possible to snip off the tops of the older and taller stems, leaving the base and sideshoots intact, and replant the clippings in front of the cluster. As they grow out, you will achieve an attractive, staggered appearance and the illusion of more plants in a smaller space. P. helferi is sold by a few commercial nurseries in the U.S. and can usually be obtained easily from fellow hobbyists.