Belonging to Plantaginaceae, the plantain family, and the genus Bacopa, also known as the waterhyssops, lemon bacopa is native to the southern and southeastern United States, portions of Europe, and South Korea.
Despite the somewhat misleading genus name, lemon bacopa is not actually a hyssop. It’s commonly confused with Bacopa monnieri, or water hyssop, and oftentimes monnieri is sold as lemon bacopa and vice versa.
However, it’s quite easy to tell the difference: lemon bacopa has five-merous, blue flowers and round leaves that smell pleasantly of lemons if disturbed, whereas water hyssop has four to five-merous white flowers and more oblong, unscented leaves.
Lemon bacopa is a hydrophyte, meaning that it is found growing solely in bogs, marshes, and other wetland ecosystems rather than terrestrially. Its ecological importance cannot be understated – its roots are quite adept at utilizing excess phosphorous, nitrogen, and even heavy metals, thus purifying the water and making it a popular plant choice in wetland remediation projects.
A variety of fish species utilize the roots and leaves (if the plant is submerged) for cover as well as to lay their eggs on, and many pollinators like the white peacock butterfly depend on lemon bacopa for larval development and nectar.
Bacopa caroliniana Growth, Hardiness & Climate
If submerged in water, lemon bacopa can grow six inches or more, depending upon water depth and light availability. It’ll grow straight up, without much lateral spread until leaves reach the surface of the water.
If planted in soil, either in an inch or two of water or simply in saturated soils, lemon bacopa will typically grow two to four inches tall before cascading over the ground, water, logs, rocks, and anything else around it. In this case, it can spread up to two feet per plant. With thick, stocky stems, this plant is easy to “train” without damaging, so you can get it to cascade and drape the way that you would like it to. If you wish to have a bushier plant, you can prune the main growing tips, which will trigger side shoots to grow.
With ample sunlight and nutrients, lemon bacopa grows quickly, so it may be necessary to trim it back from time to time as you see fit. Native to the Everglades in Florida, lemon bacopa prefers subtropical climates and is hardy in fresh as well as brackish waters. Due to being naturally found in regions (such as the Everglades) where large disturbances such as hurricanes and floods happen regularly, lemon bacopa is a tough little plant and should do just fine in your pond so long as average temperatures don’t fall below approximately 55° F (12.7° C), and it has access to either full or partial sunlight.
How to Plant Bacopa caroliniana In Ponds
Lemon bacopa can be planted in the bottom of your pond using either a gravel-like substrate, clay, or aquatic soil, on the edge of your pond as an emergent planted in one to two inches of soil/water, or in a small pot (to help control growth) either submerged or on your pond’s edge in a couple inches of water. So long as its roots are wet and warm, lemon bacopa is typically happy. It does grow best as an emergent plant, but will do just fine if submerged.
To propagate your bacopa, simply take some cuttings and plant them as described previously. You can also attach a planting weight to them and allow them to essentially plant themselves. They should be fully rooted within about a month regardless of your planting strategy.
How to Care For & Maintain Bacopa caroliniana
Lemon bacopa is pretty low maintenance, but as mentioned above may need to be trimmed down from time to time to prevent floating mats from forming. As always, clean up any trimmed or dead leaves, stems, and flowers to maintain healthy water quality. As lemon bacopa is able to extract nutrients naturally from soil, you shouldn’t need to provide any fertilizers (though if you do, be prepared for this plant to grow quite quickly).
How to Winter Bacopa caroliniana In Ponds
As a subtropical plant, lemon bacopa will not survive outside during the winter. Before the first frost hits, take as many cuttings as you’d like and remove any remaining lemon bacopa that you don’t want from your pond. Place the cuttings in a bright window indoors, either in a container of water or saturated soil. The following spring, you can plant them back in or around your pond.
Is Bacopa caroliniana Toxic, Poisonous or Invasive?
Lemon bacopa is considered non-toxic to both humans and wildlife. Research yields very little information in regards to invasiveness – it seems to only be considered invasive in South Korea. Outside of the southeastern United States, it is sometimes listed as a noxious weed, as it can overtake areas if it’s not cut back.
Is Bacopa Caroliniana Edible? Will Fish Eat it?
Pond fish can eat lemon bacopa as it is edible, but likely won’t due to its strong flavor. Even triploid grass carp, which are generalist plant eating fish that are bred to control aquatic plant overgrowth, don’t browse on lemon bacopa.
Where to Buy Bacopa Caroliniana Plants & Seeds? (UK & US)
Found readily at online outlets, in many aquarium and pond retailers, and at native plant nurseries, it’s easy to get your hands on lemon bacopa. It’s a popular and easy to grow plant, making it commonly sold and at fairly cheap prices.