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Lemon Bacopa | Bacopa caroliniana

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Publication Number: P3735-27
View as PDF: P3735-27.pdf

Emergent | Native

Yellow-green lemon bacopa (Bacopa caroliniana).
Mixed stand with lemon bacopa with one blue bloom.
Tiny, light-blue flowers emerging from lemon bacopa stems.

Also known as blue waterhyssop, lemon bacopa is a succulent species with a distinct lemony scent that is released when the leaves are crushed.

This species prefers moist shorelines where it can form a creeping mat. In clear water, it grows as a submersed plant with the tips of shoots emerging from the water column.

The leaves are relatively thick, and darker green when submerged and pale green or yellow when in air. They are paired and opposite of one another, oval to mildly triangular, and about a half-inch in length. The leaves are covered in fine hairs. The upper stems of bacopa are covered in hairs.

The flowers are small and present throughout the summer. They are pale to dark blue.

Management Value

The wildlife value of lemon bacopa is not clear. Although not a known primary food source of many animals, it likely serves as habitat for invertebrates, which feed higher organisms.

Lemon bacopa is rarely a problem species that requires treatment, as it does not expand rapidly or grow in deeper areas. However, since it does not offer significant value as habitat or as an ornamental plant, it is not a recommended species for management.

Recommended Controls

Option 1: Florpyrauxifen-benzyl (2.5-pound formulation). Florpyrauxifen-benzyl (6.75 ounces per acre-foot of water) should be applied as a submersed injection (application using a wand or hose). Determine pond volume prior to application. Do not exceed annual herbicide rate limits as stated on the product label.

Option 2: Diquat (3.73-pound formulation). Diquat should be applied as a submersed injection (0.25 gallon per acre-foot of water). Determine pond volume prior to application. Do not exceed annual herbicide rate limits as stated on the product label.

NOTE: Acre-foot = average depth of pond multiplied by pond acreage; average depth is calculated by taking the depth at 20 points across a water body and averaging the values.

The best approach is to treat ponds with herbicide when the plants are actively growing, and the water temperature is at least 60˚F. For both options, water bodies should be treated in thirds with 1 to 2 weeks between treatments to prevent oxygen depletion.

Read and follow all chemical label instructions, especially the section on the use of personal protection equipment.

Photo Credits Middle: Jeff McMillian, USDA. Provided by Almost Eden. United States, Louisiana.; Bottom: Larry Allain, USDA.

Funding provided by the Aquatic Nuisance Species Program of the U.S. Fish and Wildlife Service, Grant Award F18AP00260 to the Mississippi Department of Environmental Quality. Additional funding and support provided by the MSU Extension Service.

The information given here is for educational purposes only. References to commercial products, trade names, or suppliers are made with the understanding that no endorsement is implied and that no discrimination against other products or suppliers is intended.

Publication 3735-27 (POD-11-23)

By Wes Neal, PhD, Extension/Research Professor, Wildlife, Fisheries, and Aquaculture; Dennis Riecke, Fisheries Coordinator, Mississippi Department of Wildlife, Fisheries, and Parks; and Gray Turnage, PhD, Assistant Research/Extension Professor, GeoSystems Research Institute.

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Portrait of Dr. Wes Neal
Extension/Research Professor
Fisheries Extension
Asst Extension/Research Prof

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