Moneywort (Lysimachia nummularia), commonly called Creeping Jenny, is an adaptable perennial plant prized for its bright, coin-shaped leaves. It is popular both as a fast-spreading groundcover and as an aquatic or semi-aquatic plant in water gardens and aquariums. This species is native to Europe but has naturalized across North America, thriving in consistently moist environments. Its remarkable versatility often leads growers to question its basic requirements, particularly whether a traditional substrate is necessary for its survival and growth. Moneywort is robust and flexible; it does not strictly require a substrate to flourish.
Moneywort’s Rooting Flexibility
Moneywort’s ability to thrive without being anchored in soil or gravel stems from its unique physiological structure as a stem plant. Unlike many plants that rely solely on a primary root system for nutrient uptake, Moneywort readily produces adventitious roots directly from its stem nodes. These nodes are the points along the creeping stem where leaves and new roots emerge, a characteristic feature of its growth habit. When a stem node comes into contact with moisture, whether wet soil or water, it quickly develops a new set of roots. This mechanism allows the plant to anchor itself and absorb nutrients efficiently, regardless of whether it is rooted in the ground or merely floating in a water column. This biological flexibility means the function of a substrate is often reduced from a life-support system to a simple means of physical stability.
Cultivating Moneywort Without Traditional Substrate
The adaptable nature of Lysimachia nummularia makes it an excellent candidate for cultivation methods that entirely bypass traditional soil or gravel. In aquatic setups, Moneywort stems can be left to float freely on the surface of the water, a method often employed in ponds or aquariums. When floating, the plant receives ample light and draws all necessary sustenance directly from the surrounding water column. This reliance on water for nutrients is typical for many aquatic stem plants, which are highly efficient at absorbing dissolved minerals and compounds. Floating Moneywort can provide excellent cover for fish and shrimp, forming a dense mat of vegetation.
Growth may even be faster when floating because the leaves can access atmospheric carbon dioxide, which is more readily available than the carbon dioxide dissolved in water. Even in tanks with an inert substrate like sand, the plant has been observed to grow well by simply relying on water column fertilization.
Recommended Terrestrial and Aquatic Substrates
While substrate is not strictly necessary for Moneywort’s survival, using the right material can promote optimal growth and provide physical anchoring. For use as a groundcover, the plant requires a terrestrial substrate that is consistently moist and well-draining. Ideal soil types are rich in organic matter and have a slightly acidic to neutral pH, often found in damp woodlands or along stream edges.
The goal of a terrestrial substrate is to retain sufficient moisture without becoming waterlogged, which can lead to root rot. If the soil is too dry, the plant will struggle to root effectively from its creeping stems. In aquatic environments where anchoring is desired, an inert substrate like fine sand or small-grain gravel is often used for stability. Specialized aquatic soils, which are nutrient-rich and often clay-based, provide the best growth potential. Even in these nutrient-rich substrates, the plant’s robust nature allows it to absorb nutrients from both the roots and the surrounding water.