Alternanthera sessilis
Sessile Joyweed
Scientific Classification
Kingdom:Plantae
Phylum:Tracheophytes
Class:Magnoliopsida
Order:Caryophyllales
Family:Amaranthaceae
Genus:Alternanthera
Species:sessilis
IUCN Status:Least Concern
Quick Stats
Difficulty
Medium
Environment
Freshwater
Temperature
22°C - 28°C
pH Level
6 - 7.5
Water Hardness
36 - 215 ppm
Growth
Fast
Lighting
Medium - High
Max Height
20-50 cm
Placement
Midground
CO2 Requirements
Low
Water Flow
Medium Flow
Aquarium Building Information
Max Height
20-50 cm
Placement
Midground
Lighting
Medium - High
Growth
Fast
CO2 Requirements
Low
Water Flow
Medium Flow
Substrate
Sand
Gravel
Soil
Attachment Method
substrate
Oxygen Production
High
Waste reduction
High
About This Species
Basic Description
Sessile Joyweed, also known by fun names like Dwarf Copperleaf or Red Carpet Weed, is a beautiful stem plant that brings a wonderful splash of color to an aquarium. Unlike many typical green plants, it can develop shades of red, pink, and orange, making it a real eye-catcher. It's a perfect choice for the middle area of your tank, as it grows tall enough to create a lush background for your foreground plants without completely hiding what's behind it. Planting is as simple as gently pushing the stems into your aquarium's sand, soil, or gravel. While it's considered a 'medium' difficulty plant, don't let that scare you! It's a great choice for aquarists who have a little experience and want to try their hand at growing more colorful species. The main keys to success are providing it with a good quality light and keeping your water conditions stable. One of the best features of this plant is how it helps keep your tank healthy. It's fantastic at absorbing fish waste and leftover food from the water, which helps to keep the water clean and prevent unwanted algae. In return, it releases plenty of oxygen for your fish to breathe. If you give it the right care, Sessile Joyweed will reward you with vibrant color and contribute to a balanced, thriving aquarium.
Detailed Description
Alternanthera sessilis is a highly rewarding, albeit moderately demanding, stem plant for the aquascaper looking to introduce durable, vibrant color. Its classification as 'medium' difficulty is primarily due to its high demand for light to achieve its signature coloration. While it can survive under medium light, its leaves will often remain a dull bronze or green. To unlock the brilliant reds, magentas, and purples suggested by its 'Dwarf Copperleaf' moniker, high-intensity lighting is essential. Interestingly, its 'low' CO2 requirement makes it one of the more accessible red plants for hobbyists without a high-tech CO2 injection system. However, it's important to understand that while supplemental CO2 is not strictly necessary for survival, its addition will dramatically improve growth rate, leaf density, and color intensity. This species is a voracious feeder, as indicated by its high nutrient absorption capacity. It pulls nutrients heavily from both the water column and the substrate. For this reason, a nutrient-rich substrate like aqua soil is highly beneficial. In inert substrates like sand or gravel, the regular use of root tabs is crucial to prevent deficiencies. A comprehensive liquid fertilizer, dosed regularly, is also a must. Pay special attention to iron and micronutrient levels, as a lack of iron will lead to pale, washed-out colors, even under strong light. Due to its moderately fast growth, A. sessilis requires consistent pruning to maintain its desired shape and prevent the lower leaves from being shaded out. To encourage bushier, denser growth, trim the top 5-6 inches of the stems and replant them in the substrate next to the parent plant. Over time, this 'topping' method will create a thick, colorful hedge. In aquascaping, its vertical growth makes it ideal for creating 'streets' of color in a Dutch-style layout or for acting as a stunning midground focal point that contrasts beautifully with green flora. The need for medium water flow serves a dual purpose: it ensures a steady supply of nutrients to all parts of the plant and helps keep its leaves free from detritus, which can block light and promote algae. This plant is a fantastic biological filter; its ability to rapidly consume nitrates and phosphates helps to maintain water quality and out-compete algae, contributing to a cleaner, more stable aquatic ecosystem.
Scientific Description
Alternanthera sessilis, a member of the Amaranthaceae family, is a cosmopolitan amphibious herb with a pantropical distribution. This extensive natural range signifies a high degree of genetic diversity and phenotypic plasticity, allowing it to thrive across a broad spectrum of limnological conditions. Its IUCN status of 'Least Concern' is consistent with its prevalence as a hardy, often weedy species in both semi-aquatic and terrestrial environments. The specific epithet 'sessilis' is a key morphological descriptor, referring to its leaf arrangement where the lanceolate to oblong-obovate leaves are attached directly to the stem's nodes without a petiole. In its submersed aquatic form, the plant's pigmentation is highly variable and directly correlated with environmental parameters. The synthesis of anthocyanins, the pigments responsible for its characteristic red and violet hues, is primarily induced by high levels of irradiance (PAR). While its CO2 requirement is low relative to other red stem plants, suggesting a capacity for efficient carbon fixation or bicarbonate utilization, its growth rate and pigment expression are significantly enhanced under carbon-supplemented conditions. Its physiology is characterized by a high rate of nutrient assimilation. The listed high nutrient absorption and bioload reduction capabilities indicate its effectiveness as a tool for phytoremediation. It actively sequesters inorganic nitrogen and phosphorus compounds from the water column, incorporating them into its biomass and thereby reducing the nutrient load of the aquatic system. This plant's tolerance for a wide range of water hardness (36-215 mg/L CaCO3) and pH (6.0-7.5) further demonstrates its robust and adaptable nature. In an aquarium setting, propagation is almost exclusively vegetative, occurring via fragmentation and the planting of apical cuttings. When grown emersed, A. sessilis produces its characteristic inflorescences: small, sessile, white, and chaffy flowers clustered in the leaf axils. Its marginal tolerance for salinity (up to 0.5 ppt) suggests an ecological niche that can include the upper reaches of estuaries and other slightly brackish water bodies.
