Joseph's coat (Alternanthera dentata)
Discover Joseph's coat (Alternanthera dentata), a low-maintenance perennial prized for its striking purple foliage, ideal for borders in Zones 10-11.
Complete Plant Information
Overview
Joseph’s coat, scientifically known as Alternanthera dentata, is celebrated primarily for its dramatic, rich purple to burgundy foliage, offering vibrant contrast in garden settings where other plants feature green leaves. This tropical perennial thrives outdoors as a summer annual in most temperate climates but is winter hardy in USDA Zones 10 through 11. It is a generally upright plant that forms spreading foliage mounds, making it highly versatile for various landscaping applications.
This plant requires organically rich, consistently moist, well-drained soil to flourish, with full sun exposure developing the most intense leaf coloration. Despite its tropical origins, Alternanthera dentata is relatively low maintenance when its basic needs for consistent moisture and adequate sunlight are met throughout the growing season. Gardeners value this species for its reliable texture and deep color throughout the summer months.
While Alternanthera dentata produces insignificant white flowers seasonally, its primary ornamental appeal is entirely foliage-driven, similar in appearance to coleus. Whether used as an annual bedding plant, an edger, or grown indoors, this copperleaf provides year-round interest if successfully brought inside for winter.
Fast Facts
- Plant Family: Amaranthaceae
- Plant Type: Herbaceous perennial
- Native Range: West Indies
- Hardiness Zones: USDA Zones 10-11
- Size at Maturity:
- Height: 1-3 ft
- Spread: 1-2 ft
- Bloom Time: Seasonal bloomer
- Bloom Description: White
- Sun Exposure: Full sun to part shade
- Water Needs: Medium
- Maintenance Level: Low
How to Grow
Planting Alternanthera dentata should occur after the danger of frost has passed when grown as an annual, typically utilizing transplants purchased from nurseries. Ensure the location provides organically rich, well-drained soil. Consistent moisture is critical for this plant; the soils absolutely must not be allowed to dry out, especially during intense summer heat.
For optimal caretaker results, provide full sun, as this location develops the best foliage colors in cultivars of Joseph’s coat. Watering should be consistent, adhering to a medium needs schedule—never allowing the soil substrate to become parched. Maintenance is generally low, focusing mainly on encouraging a bushy habit.
Pinching the stems or shearing the plant regularly will keep your Alternanthera dentata compact and bushy, preventing it from becoming leggy. For gardeners wishing to overwinter their plants, they can be potted up or cuttings can be taken in late summer for indoor cultivation near a bright, sunny window.
If starting from seed, begin indoors in late winter and transplant only after the last frost date has passed. Be judicious when selecting seedlings, as the resulting leaf color quality can vary significantly among non-selected garden varieties.
Landscape Uses
Joseph’s coat is highly effective when used where a burst of deep color is needed near the front of a border or as crisp, low edging. Its dense, bushy nature makes Alternanthera dentata an excellent choice for mass plantings, where its foliage creates a saturated carpet effect contrasting beautifully with lighter-colored plants. It also works exceptionally well as a striking feature in large containers.
When designing beds, consider companion planting with species that appreciate similar sun and moisture levels but offer contrasting leaf shapes or colors, such as bright green grasses or silver-leafed groundcovers. Its use as an annual allows gardeners in cooler regions to enjoy the intense tropical look of copperleaf for just one season.
For those overwintering the plant indoors, it serves as an attractive houseplant. Provide it a bright, sunny location indoors to mimic its outdoor preference, ensuring consistent soil moisture to keep your specimen of Alternanthera dentata vibrant until spring planting time.
Standout Features
Flower Qualities
- Insignificant
Noteworthy Characteristics
Alternanthera dentatais native to the West Indies and Brazil. It is a generally upright plant that typically forms spreading foliage mounds to 12-30” tall. Although species plants feature linear-lanceolate to ovate, toothed green leaves (to 3.5” long), it is the purple-leaved cultivars that have become popular garden plants. Foliage is suggestive of coleus. White apetalous flowers appear in small axillary clusters in late fall to winter, but are insignificant. Flowers are usually observed in St. Louis only on houseplants or on container plants brought inside for overwintering. Plants in the genus Alternanthera have a rather large number of descriptive common names, including but not limited to Joseph’s coat, copperleaf, calico plant, bloodleaf, joyweed and parrot leaf, all in reference to the often brilliantly colored leaves which provide foliage contrast to gardens and container plantings. A. Dentata cultivars are noted for their rich purple to burgundy leaves.Genus name comes from the Latin words alternans meaning “alternating” and anthera meaning “anther”, in reference to alternate anthers in the genus are barren.Specific epithet means toothed for the toothed leaves
Tolerances
- No serious insect or disease problems
Potential Problems
This plant generally exhibits very few pest or disease issues, making copperleaf, or Alternanthera dentata, a reliable choice for low-maintenance gardening. Serious problems related to insects or fungal infections are rare when cultural needs are met.
The main cultural challenge involves maintaining adequate soil moisture. If the soil is allowed to become dry, the plant will quickly show stress, leading to reduced foliage quality and potential collapse, especially when siting it in full sun.
To ensure success, focus cultural care on soil composition (organically rich and well-drained) and routine watering. This proactive approach usually eliminates the need for chemical intervention against pests or diseases.
Frequently Asked Questions
What hardiness zones is Joseph’s coat suitable for?
Alternanthera dentata is reliably hardy in USDA Zones 10 through 11, meaning it can survive winter outdoors in these warmer regions.
How large does Joseph’s coat grow?
This plant typically reaches a height between 1 and 3 feet tall, with a spread ranging from 1 to 2 feet wide, forming spreading foliage mounds.
What sun exposure does Alternanthera dentata need?
For the richest, most desirable foliage coloration, Alternanthera dentata performs best in full sun, although it can tolerate partial shade.
When does Joseph’s coat bloom?
This plant blooms seasonally, featuring small clusters of insignificant white flowers, typically observed late in the season or only on indoor winter specimens.
Conclusion
Alternanthera dentata, commonly known as Joseph’s coat, is an invaluable resource for gardeners seeking reliable, intense foliage color with minimal maintenance effort. Its deep purple hues provide excellent visual texture when massed or used as edging. Before planting, confirm your location falls within USDA Zones 10-11, or plan to treat this magnificent copperleaf as a treasured annual.
Propagation Tips
For gardeners looking to expand their collection of this colorful foliage plant, propagation is straightforward. Since Alternanthera dentata is a tropical perennial, it lends itself well to vegetative propagation, especially for gardeners outside its hardiness range who plan to overwinter them indoors.
The simplest method is taking tip cuttings in the late summer. Cuttings should be inserted into a moist, well-drained medium and kept in a warm, bright location until they root. This ensures you have healthy, genetically identical replacements ready for next season.
Alternatively, plants can be grown directly from seed started indoors in late winter, though attention must be paid to selecting only the seedlings exhibiting the best, most vibrant leaf color for transplanting after the last frost date.
Companion Planting
When utilizing Joseph’s coat in the landscape, select companions whose cultural needs—medium water, consistent moisture, and bright light—mirror its own. Pairing it with silvery or chartreuse foliage creates a striking dynamic against the deep burgundy of the Alternanthera dentata cultivars.
Consider low-growing silvery lamb’s ears (Stachys byzantina - where climate permits) or fine-textured ornamental grasses that can take similar amounts of sun. These textures and colors will help the dense mounds of the copperleaf truly stand out in a mixed border setting.
Since the foliage of Joseph’s coat is the main draw, avoid pairing it with plants that demand too much pruning or heavy fertilization, keeping the overall design as low-maintenance as possible, reflecting the nature of Alternanthera dentata.
