Water Hyssop - Bacopa monnieri

Water hyssop (Bacopa monnieri) is an herbaceous perennial that occurs throughout Florida, the rest of the lowest tier of states across the U.S., and into the West Indies and parts of Central America. It is a mat-forming species that creeps across the ground, rooting as it advances from the nodes on its stem.  Ultimately, individual plants form large masses that meet each other and become indistinguishable.  It dies back to the ground each winter, however, and returns again in early spring.
In more tropical parts of its range, it is evergreen. As its name implies, water hyssop is a wetland plant that thrives at the edges of both freshwater and brackish water habitats. If  the ground is moist, it can persist in lawns and the edges of disturbed sites and it will tolerate partial sun as long as its moisture needs are met.  It prefers full sun and plenty of water.
Water hyssop rarely stands above 1-2 inches in height.  The lime green stems and the small oval leaves that are opposite each other are succulent in appearance and make it attractive as a ground cover. The leaves are without fragrance, unlike its close cousin, lemon bacopa (B. caroliniana).
Flowering occurs from spring into mid-fall, except in the more tropical parts of its range where it can bloom year round.  Small white to pinkish tubular blooms are lined in violet and composed of five petals. They attract the attention of small pollinators.
Water hyssop is the preferred larval food for White Peacock butterflies - the butterfly pictured below. They seek it out above other plants, like Phyla nodiflora, that are also sometimes used. We have a nice patch in our landscape that we planted next to the edge of our small landscape pond. The plants grow out into the open water as well as creep along the pond edge. It has never, however, ventured out into the rest of the yard as it is too dry.  Butterfly gardeners can also use this plant in hanging baskets when landscape conditions preclude adding it directly into the ground.  It is somewhat forgiving of very short-term drought, but it should be watered regularly. Because of its value to butterfly gardeners and its attractive foliage, water hyssop is rather widely propagated by commercial sources and should not be too difficult to find.