Description
Plant Profile
Meet Persicaria praetermissa, commonly known as Ruby Smartweed, a rare, fast-growing aquatic stem plant native to the tropical and subtropical marshes, riverbanks, and wetlands of Asia and Australia. It stands out with slender, spearhead- to arrow-shaped leaves featuring distinct basal lobes, a leaf geometry that gives it a textural contrast most stem plants can’t match. Grown emersed, it keeps things green, but take it underwater, and it transforms, developing rich reddish-brown, copper, and deep magenta tones instead.
*Form Notice: Photos display this plant in both its emersed (above-water) and submerged forms. Depending on nursery availability and seasonality, you may receive this plant in either form. Learn more about what to expect by reading our guide on Emersed vs. Submerged-Grown Aquatic Plants.
Key Features & Benefits
Distinct spear-head leaf shape develops rich copper, reddish-brown, and magenta tones under submerged conditions.
Versatile across submerged aquariums, paludariums, and open-top bog gardens.
Rapid growth acts as a natural nitrate sponge for crystal-clear water.
Care & Planting Instructions
Remove lead weight (or pot) and cotton wrap (or foam) surrounding the roots, then strip lower foliage so bare stems anchor cleanly into soil without rotting.
Use fine-tip pinsettes to push individual stems 1 to 2 inches into substrate, spacing them slightly apart so light reaches lower leaves.
Provide medium-to-high lighting; while adaptable, adding pressurized CO2 and regular liquid nutrient dosing with iron yields significantly faster growth, larger leaves, and deeper reddish-brown pigmentation. See our guide to growing red aquarium plants.
Maintain stable water parameters and avoid sudden environmental shifts to prevent leaf melt or stem rotting.
Trim main stem tops with straight scissors once stems reach the desired height, and replant trimmings directly into substrate to propagate and expand coverage. Read our trimming & propagation guide for details.
Quick Facts
Listed information should be treated as general guidelines only. Team Buce Plant encourages you to do thorough research to ensure healthy growth!
Attribute
Specification
Scientific Name
Persicaria praetermissa / Polygonum praetermissum
Common Name(s)
Persicaria Praetermissa, Ruby Smartweed, Polygonum Praetermissum
Family
Polygonaceae
Plant Type / Taxonomy
Stem Plant / Marginal Bog Plant
Care Difficulty
Easy to Moderate
Light Requirement
Medium to High
CO2 Requirement
Recommended (Enhances growth rate and reddish-brown tones)
Placement / Usage
Midground / Background Bushing / Paludarium Marginal
Height / Size
4–12”+
Growth Rate
Fast
Water Parameters
pH 6.0–7.5
Propagation Method
Cuttings (Cut stem and replant tops)
Origin
Asia & Australia
Frequently Asked Questions
1. Why are the lower leaves falling off my stem plants?
Lower leaf loss (leggy stems) usually occurs when lighting cannot reach the bottom of the plant due to overcrowding or shading from larger plants. Spacing individual stems slightly apart during initial planting and maintaining strong light penetration will keep lower leaves healthy.
2. How do I bring out the reddish-brown coloration on Persicaria Praetermissa?
While Persicaria Praetermissa remains predominantly green under lower lighting, providing medium-to-high light intensity, pressurized CO2, a nutrient-rich aquarium substrate, and regular dosing of liquid micro and macronutrients (especially iron) will bring out deep red, brown, and copper foliage tones.
3. How do I transition Persicaria Praetermissa from emersed to submerged growth?
When transitioning from emersed to submerged growth, plant bare stems securely into rich substrate under good lighting and keep water parameters stable. As new growth adapts, the plant will shed its stiffer emersed foliage and sprout soft, brightly colored underwater leaves with reddish-brown highlights. Once new shoots take root, trim away old lower growth to encourage dense branching.
