Staurogyne repens grows taller than carpet plants such as Utricularia graminifolia but are still much shorter than typical stem plants. Under higher light levels it grows densely and hugs the hardscape. It is an ideal for intermediate placement between carpeting plants and taller mid/back ground plants.
Staurogyne repens originates from South America and has become popular in the hobby due to its versatility in aquascaping. It is a short green stem plant that forms dense bushes under higher light levels. Its ability to be pruned into nice contours and short height makes it great for aquascaping. It blends easily with other plants and is useful in aquascapes that want to express a sense of natural mixing of plants. Higher light levels cause the plant to spread sideways to surrounding areas with a creeping stem, while lower light levels cause the plant to grow vertical with longer internodes like a typical stem plant. In crowded conditions, the plant will also grow more upright.
As it is not as fast growing as other common stem plants, it can be easily shaded by more aggressive growers. Thus, it is best positioned in the mid or foreground of the tank with some spacing from surrounding plants where it can receive unobstructed light.
Staurogyne repens is not a high demand plant compared to other difficult aquatic plant species but is also not as hardy as species typically grown in low tech tanks such as water Wisteria. It grows to its best form in CO2 injected tanks, though it is quite commonly used in non CO2 injected tanks as well - where it takes on a more vertical form and grows less dense.
It grows well in aquasoil or clay-soils, but its hardiness means that it will grow in inert substrate as well as long as there are other ways for it to obtain required nutrients.
Staurogyne repens rot/melting
This is one issue that is unique to Staurogyne repens. When conditions are unstable, and the tank goes through some fluctuations or when the plant is still acclimatizing to a new tank, it is susceptible to a type of melting that spreads to adjacent plants (both adjacent staurogyne plants as well as other species). It is unconfirmed what exactly causes this; whether it is a virus/bacteria etc. However its occurrence has been common enough for us to study its general progression in a tank. It usually starts with pale, translucent brown patches in the leaf (red circle below), which then spreads to surrounding plants leading to melting of whole leaves eventually. This melting will often also spread to other plant species. However, in many cases, the bare stems can recover after the melting process has passed. There is no known cure as of now (2021), although improving growth conditions as a whole can return the batch of plants to health more quickly. Tank instability and large parameter shifts - ammonia spikes etc can trigger the melting. It is much more common in new setups and newly planted plants, and rare among established plants.
If detected early, affected leaves should be removed entirely. Sometimes this is enough to limit the spread.
Early stages of Staurogyne melt; if all affected leaves were removed, the spread could be halted. A single brown spot is often sufficient enough to diagnose this disease.
Key success factors
Sufficient light (70-90 umols of PAR) causes more lateral growth, insufficient light causes more vertical growth. At least 50umols of PAR on the substrate level is recommended.
Overall tank stability and biological maturity prevents melting. Read more on this here.
CO2 injection gives better density, leaf size, and plant health.
Can be grown well in hard water, and tolerate a large range of water parameters.
Inadequate fertilization results in patchy or pale colored leaves, regular fertilization should be done either through the rootzone or water column.
Trimming and propagation
Staurogyne repens take trimming very well. The creeping rhizome or stem can be cut at a leaf node, and the remaining stem will sprout new shoots. Staurogyne repens bushes take over-crowding well - meaning that they can grow large and dense over time without suffering all that much, which makes them great for lower maintenance aquascapes.
Over crowded bushes tend to have deteriorating lower portions. This means that large bushes that are not trimmed often can have mostly bare stems in the lower levels. The aquarist has therefore two choices. You can trim the Staurogyne repens bush often, and trim them low, which allows the bush to rejuvenate itself, or you can trim it once in a long time, by then which the bottoms might have started to deteriorate and you would need to do replanting of tops.
Propagation is simple as with other stem plants. Just cut off a length of the top shoot (around an inch or longer so that it is easier to plant) and plant straight into the substrate.