Pogostemon Erectus

The stem plant that aquarium shops have sold as Pogostemon erectus for years was identified by Christel Kasselmann in 2019 as Pogostemon deccanensis, and that is the newer name. The true P. erectus, a close relative from the same region, turned out to be unsuited to submerged culture, so almost everything in the hobby under the old label belongs here. It was first collected for aquarists in the western Indian state of Maharashtra.

At first glance it resembles Rotala verticillaris and some forms of Rotala mexicana, but it grows more strictly upright and larger, reaching about 40 cm in the aquarium, and it has its own violet flower spikes when kept emersed. It grows best at 24 to 28 °C and pH 5 to 7. It needs bright light and plenty of CO₂ to stay dense; with low nitrogen it grows at a manageable pace, while heavy feeding makes it take off quickly.

Fine light-green foliage makes it a useful background plant, particularly beside red stems such as Persicaria praetermissa. Cutting the shoot tip encourages lateral shoots, so a group thickens over time and needs regular trimming to keep its shape.