Lagarosiphon major Care Guide
Lagarosiphon major is a southern African oxygenating stem plant with curly recurved leaves that prefers cool to temperate water and grows quickly.
Compiled by Aquairi from published sources · Published · Updated
Overview
Lagarosiphon major is a submerged stem plant in the family Hydrocharitaceae, known for its densely packed curly, recurved leaves. It is a strong oxygenator best suited to cooler aquariums and is sometimes confused with Egeria species in the trade.
Taxonomy
- Family: Hydrocharitaceae
- Genus: Lagarosiphon
- Scientific name: Lagarosiphon major
- Common synonyms: African curly waterweed, curly waterweed; Elodea crispa (trade name)
Habitat
The species is native to southern Africa, where it grows submerged in freshwater. The curly or recurved leaf arrangement is reflected in its older trade name Elodea crispa. It adapts well to cool and temperate conditions.
Aquarium requirements
- Placement: background
- Temperature: 12-24 °C (54-75 °F)
- pH: 6-8
- GH: 4-20 °dGH
- Lighting: medium to high
- CO2: not required (responds to 5-40 mg/L)
- Maximum height: about 60 cm
Growth and care
Lagarosiphon major grows fast and is rated easy. It prefers cooler water and may decline if temperatures stay above roughly 24 °C for extended periods, which makes it a good fit for unheated or coldwater tanks. Trim every ten days or so to keep growth dense.
Propagation
Propagation is by cuttings and fragmentation. Stems may be rooted in substrate or left floating, and side shoots quickly develop into new plants.
Notes on invasiveness
Lagarosiphon major is a regulated invasive species in several regions. It is listed on New Zealand's National Pest Plant Accord, is treated as a noxious weed in the United States, and since 2016 is on the European Union's list of Invasive Alien Species of Union concern, where its sale and release are prohibited. Check local regulations before keeping it.
Propagating Lagarosiphon major (Curly Waterweed)
Overview
Lagarosiphon major — African elodea, curly waterweed or oxygen weed — is a monocotic aquatic plant native to southern Africa. It is a robust freshwater oxygenator with densely packed, curly leaves carried along long stems, and it tolerates cool to temperate water better than most tropical stem plants.
Lagarosiphon is dioecious, with male and female flowers on separate plants, and leaves are borne in an alternate, sub-opposite or whorled arrangement depending on the species. In cultivation and in its invasive range it reproduces vegetatively rather than by seed, which makes propagation trivial and escape catastrophic.
Propagation Method
Curly waterweed propagates by fragmentation and stem cuttings. A detached piece of stem will continue growing and root on its own, so the plant multiplies from any broken-off segment. There is no need for seed, flowering, or special technique.
Step-by-Step
- Select a strong, leafy stem and cut a section 10–15 cm long with sharp scissors.
- Trim away leaves from the lowest few centimetres of the cutting.
- Push the bare base into the substrate, or weight a bundle down so it stays put.
- Roots emerge from the lower nodes and anchor the new plant.
- Once growth resumes, the cutting behaves as an independent plant.
- Capture and bag every loose fragment — even a small piece can establish.
Conditions for Healthy Growth
This is a cool-water species, comfortable from roughly 12 to 24 °C, at pH 6–8 and across soft to hard water. It grows well under medium lighting without added CO2, which suits unheated or temperate setups. Its cold tolerance is precisely what lets it overwinter and dominate in cooler climates where it has invaded.
Trimming & Maintenance
Trim about every week to ten days, topping stems before they crowd the surface. Replant healthy tops and discard tired lower portions. Because the brittle stems shed fragments freely, always net the clippings out immediately and never rinse trimmings down a drain.
Common Challenges
Day to day, the practical challenges are its vigorous, fragment-prone growth in cool water. Both are controlled by frequent trimming and meticulous collection of every loose piece.