Alternanthera ficoidea is an heirloom plant that was popular during the Victorian era in formal gardens, and has made its way into our annual gardens with several new cultivars from Mexico and South America. Joseph's coat is the common name for this plant, but it is sometimes confused with a yellow green form of summer poinsettia that is also called Joseph's coat. Landscapers call the plant chartreuse alternanthera to avoid the common name confusion. It is also called golden parrot leaf, golden alternanthera or chartreuse calico plant.
Chartreuse alternanthera has eye-catching yellow green foliage, compact growth habit, durability and nonstop color from early spring until fall frost. The growth habit is 4 to 8 inches tall and 6 to 12 inches wide. It is often used in formal knot gardens or as edging to define plant beds. The plant enhances or echoes other colors, making them appear more vibrant. Alternanthera is grown for its foliage. Its small, greenish white flower is borne in the leaf axis and hidden by the foliage. Chartreuse alternanthera does best in full sun with moist, well-drained soils. Light pinching will keep plants compact.
Alternanthera dentata 'Purple Knight' is a frost-tender perennial grown for its dark purple foliage and can be used as a beautiful contrast against other plants in less formal beds and flower borders. The rich color is only produced in full sun and makes a dramatic accent in sunny gardens. To maintain a compact habit, regularly pinch out the growing tips. To keep a formal appearance, use pruning shears to trim the plants in summer. Plant in well-drained soil; water regularly during summer. The growth habit is 18 to 36 inches in height with an equal spread. The purple leaves excel in high heat and humidity. This plant looks great with rudbeckia and lantana.
Look for Alternenthera during summer in the entrance garden at the JC Raulston Arboretum. This planting, of mainly tropical annuals and tender perennials, is a celebration of color, texture and form.