Creeping Jenny, botanically known as Lysimachia nummularia, is a popular choice for water gardens due to its vibrant, trailing foliage and tolerance for saturated conditions. This herbaceous perennial, sometimes called moneywort, forms dense mats of round, coin-shaped leaves that cascade over pond edges, rocks, and waterfalls. Its rapid growth and ability to thrive in wet environments make it an attractive ornamental plant for softening the hard lines of aquatic features. The plant’s roots help filter water, and its dense growth provides shelter and shade for aquatic life, contributing to a healthier pond ecosystem.
Choosing the Right Placement and Materials
Selecting the proper location is the first step to successfully establishing Creeping Jenny in a pond environment. Lysimachia nummularia performs best in a location that receives full sun to partial shade, where the leaves develop a brighter golden hue in higher light levels. The plant is classified as a marginal or bog plant, meaning it thrives in shallow water or consistently moist substrate. Optimal planting depth involves placing the crown so it is just at or slightly above the water line, or submerged in water up to 2 to 6 inches deep over the root ball.
Standard garden soil should be avoided because its high organic content and fine particles can introduce excess nutrients into the water, potentially leading to algae blooms. Instead, use specialized aquatic planting media, which is formulated to be dense, non-floating, and low in organic matter. Heavy materials like pea gravel, coarse sand, or baked clay products are suitable substitutes for anchoring the plant.
Containers for planting should be porous fabric pots or solid plastic containers specifically designed for aquatic use. Fabric pots allow for better water circulation and gas exchange, while plastic pots should have holes covered with weed fabric to prevent the planting media from escaping. The container serves to restrict the plant’s aggressive growth. Using a heavy media ensures the container remains stable on marginal shelves or in the bog area of the pond.
The Planting Process: Step-by-Step Installation
Before placing the plant in the pond, gently rinse the roots to remove any residual soil from the nursery pot, as standard nursery soil can pollute the pond environment. Trimming any overly long or damaged roots can encourage new, healthy growth once planted.
The primary method involves using an aquatic container, which should first be lined with a piece of burlap or weed barrier fabric to contain the substrate. Fill the container approximately halfway with the chosen planting media, such as pea gravel or specialized clay granules. Position the Creeping Jenny plant in the center of the container, spreading the roots outward over the initial layer of media.
Next, carefully fill the remainder of the container with the heavy media, ensuring the plant’s crown—where the stems meet the roots—remains at or just below the surface. Do not pack the material tightly, as the roots require some space to grow and spread. Once filled, the top layer can be capped with a thin layer of fine gravel to further prevent the substrate from washing out when submerged.
Gently lower the potted plant onto the marginal shelf or chosen planting area, minimizing any disturbance to the media. The goal is to place the container so that the top of the pot is located within the plant’s preferred water depth range. For a more natural appearance, bare roots can be tucked directly into the crevices between pond rocks or integrated into a gravel-filled stream bed, where they will quickly anchor themselves.
Managing Growth and Ensuring Plant Health
Creeping Jenny is known for its vigorous, sprawling nature, requiring routine management to prevent it from dominating the pond environment. It spreads rapidly by sending out runners that root wherever they touch moist substrate or water, which is why container planting is often recommended. Regular inspection is necessary to trim back any stems that stray too far or begin to choke out neighboring marginal plants.
Pruning should be done with sharp shears, removing excess runners that extend over the main pond surface or into areas where they are not wanted. These trimmings can be easily propagated by simply placing the severed stems back into moist soil or water, providing new plants if desired. Consistent maintenance ensures the plant remains an attractive feature rather than a dominant weed.
The plant generally requires little to no supplemental fertilization once established in a pond with fish. During the late fall and early winter, the foliage will typically die back, especially in colder climates, but the plant is hardy and will return from the roots in the spring.
In regions with prolonged, deep freezes, plants placed in shallow water may be vulnerable to damage. To overwinter them, simply trim back the dead foliage and lower the entire container into a deeper section of the pond that will not freeze solid. This practice protects the root system, allowing the Creeping Jenny to resume its vibrant growth when temperatures warm in the spring.