By Paul A. Thomas
University of Georgia
It's prized for its eye-catching yellow-green foliage, compact growth habit, durability and ability to provide nonstop color from early spring until fall frost.
Joseph's Coat is an heirloom plant that was popular in the Victorian era when formal gardens were in vogue. Today there is new interest in it, thanks to exciting new cultivars from Mexico and South America, like Chartreuse.
Easy to growIt's a choice plant for today's part-time gardener because it provides season-long color with little routine care. It has small, greenish-white flowers in leaf axils. But they're usually masked by the foliage and are indistinct.
The plants grow in a compact, mounded shape 6 to 12 inches tall and 12 to 24 inches wide. The leaves are opposite and linear, a half-inch to 1 inch long. Both stems and leaves are bright yellow-green.
Chartreuse Joseph's Coat is brightest when planted in full sun. It will perform well, though, in morning sun and afternoon shade.
Moist, well-drained soils are essential. Like other annual plants, it requires scheduled irrigation to keep looking its best.
Light pinching of the terminal shoot throughout the season will keep it compact. In formal landscapes, plants are sometimes sheared to provide a uniform shape.
By any other nameChartreuse Joseph's Coat is sometimes confused because it has many common names: Golden Parrot Leaf, Golden Alternanthera, Chartreuse Calico Plant. A yellow-green form of Summer Poinsettia (Amaranthus) is called Joseph's Coat, too. Landscapers call it Chartreuse Alternanthera.
The plant has many landscape uses. It's a favorite in formal knot gardens or as edging to define plant beds. Theme parks, like Disney World in Orlando, Fla., use it to create intricate, eye-catching designs in the landscape.
Landscapers call Chartreuse Joseph's Coat an "echo plant" because it tends to enhance or echo other colors. It makes them look more vibrant. That's particularly true with magenta, purple or blue.
There's moreIt's a favorite in container gardens, too, and in baskets where it spills over the side like froth from a bubbling stream.
In formal beds where plants will be sheared as one unit for mass effect, set plants 12 inches apart. In beds where the plants will be seen as individuals, space them 18 to 24 inches apart.
Fertilize Chartreuse Joseph's Coat with a complete, slow-release fertilizer such as Osmocote 18-6-12 at planting time. Follow the label directions. You shouldn't need to fertilize again.
Adding 2 to 3 inches of a fine-textured mulch, such as pine straw or pine-bark mininuggets, at planting will help keep the soil more uniformly moist. Don't be tempted to water every other day. The plant can handle dry periods and even long-term drought with infrequent watering.
(Paul Thomas is an Extension Service horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.)