Pogostemon stellatus

Overview

Pogostemon stellatus is an aquatic, perennial herb of the mint family, Lamiaceae. It used to be placed in the genus Eusteralis, which is why many aquarists still know it as "Eusteralis". It is a close relative of patchouli (Pogostemon cablin), the source of patchouli oil.

Because its range is so large, many colour and leaf forms occur in the wild. In the aquarium trade and aquascaping hobby it is fairly common yet highly prized, and Tropica singles out its beautiful shape and colour. It is also demanding, so it suits experienced aquarists best.

Appearance

A stem plant with narrow leaves arranged in whorls ("stars") along an upright stem. According to Tropica, stems reach 20–60 cm tall and up to 10 cm wide; after two months in the tank the plant is typically 15–30+ cm tall.

Colour and leaf shape depend strongly on where the plant comes from: many different colour and leaf forms occur in the wild. A shortage of micronutrients makes the leaves pale.

Plants in shops are usually short and compact because they are grown in marshy (emersed) conditions; they only show their full glory once planted in the aquarium.

Care

• Light: high; Tropica stresses that it needs intensive lighting.
• CO2: high demand (Tropica: about 15–25 mg/L); it does not grow well without added CO2.
• Fertiliser: micronutrients are needed, otherwise leaves turn pale.
• Placement: stems grow up to 60 cm tall; the sources do not specify a planting zone.
• Temperature, pH and hardness: not given in the sources used.
• Quirk: even in good conditions growth sometimes stops suddenly.

Tropica rates it as Advanced: it is difficult to grow in aquariums.

Fertilizing

According to Tropica, a shortage of micronutrients leads to pale leaves, which is a sign the aquarium needs fertiliser. The plant needs intense light and added CO2; without full nutrition and CO2 it grows poorly.

Breeding

Tropica classes Pogostemon stellatus as a stem plant, but the sources used do not describe its propagation in detail. For the closely related Pogostemon quadrifolius, Tropica recommends replanting head cuttings to get a denser stand and notes that side shoots can also be used, although they grow a little more slowly.

Fun facts

• The genus Pogostemon belongs to the mint family; its best-known member is patchouli (Pogostemon cablin), grown for its scented oil.
• Other members of the genus, such as Pogostemon erectus and Pogostemon helferi, are also grown in aquariums.
• Thanks to its huge natural range, the species occurs in many colour and leaf forms. Modern cultivars and hybrids include 'Dassen', 'Kimberley', 'Narrowleaf' and 'Octopus' (Tropica, however, treats "Octopus" as a separate species, Pogostemon quadrifolius).
• The IUCN Red List assesses it as Least Concern (LC).
• English Wikipedia's list of aquarium plants gives it the trade name "Star Rotala", although it is not a Rotala.