Our horticulture team at Coastal Maine Botanical Gardens is working on a new vertical wall idea for the summer of 2014. Today, we were brainstorming which plants to use in the vertical panels. Someone mentioned Sedum ‘Angelina,’ another idea was Lysmachia nummularia ‘Aurea,’ and then I remembered Joseph’s Coat or Alternanthera ficoidea. Alternanthera is a tender perennial (hardy to USDA zone 10) native from Mexico to Argentina which is primarily grown for its foliage. The leaves on the plants are small and vary in appearance from being an inch wide to some cultivars which have thread-like foliage.
The Alternanthera would work in our green wall idea because it would provide us with some interesting colors in a fast growing plant. In our zone 6a gardens here on the coast of Maine, we would need to start the plants in late April or early May in a greenhouse to get them rooted in and growing. Probably in mid-June, we could place the vertical panels out into the garden. In order for Joseph’s Coat to continue growing successfully, the temperature needs to be consistently above 55-60 degrees. As summer goes on, the warmer it gets, the stronger it will grow. By mid-summer, each plant should be around a foot wide and could be a foot tall. The great thing about Alternanthera ficoidea is that it can be sheared into a tight form. Many Victorian gardens utilized Joseph’s Coat as a tightly clipped annual in bedding schemes.
Joseph’s Coat grows best in full to part sun, in acidic, moist but well-drained soil. In warmer parts of the country, you might want to double check if you can plant Alternanthera. It is closely related to the noxious alligator weed. In warm areas where alligator weed is a problem, different insects that feed on it have been released to try to control its growth. These insects might go after the ornamental Alternanthera as well.
Some of the more popular cultivars include: ‘Party Time’ – a tricolor selection with white, red, and green colored leaves, ‘Red Threads’ – a dark red, finely leaved selection, and ‘Yellow Form’ – a chartreuse colored form. We will probably use ‘Yellow Form’ on our wall because of the pattern we are trying to paint.
Have you grown Joseph’s Coat in your garden? What was your experience with this plant?