Alternanthera, Calico Plant, Joseph's Coat, Ruby Leaf 'Purple Knight'

Alternanthera brasiliana

Family: Amaranthaceae
Genus: Alternanthera (al-ter-NANTH-ur-uh) (Info)
Species: brasiliana
Cultivar: Purple Knight
Synonym:Alternanthera dentata


Tropicals and Tender Perennials

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun

Sun to Partial Shade


Grown for foliage

Foliage Color:



6-12 in. (15-30 cm)

12-18 in. (30-45 cm)


24-36 in. (60-90 cm)


Not Applicable

Where to Grow:

Grow outdoors year-round in hardiness zone

Can be grown as an annual



Bloom Color:

White/Near White

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Bloom Size:

Unknown - Tell us

Bloom Time:

Blooms repeatedly

Other details:

May be a noxious weed or invasive

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:


Propagation Methods:

From softwood cuttings

Seed Collecting:

Seed does not store well; sow as soon as possible


This plant is said to grow outdoors in the following regions:

Clayton, California

Santa Clara, California

Bartow, Florida

Belleview, Florida

Brooksville, Florida

Deland, Florida

Jacksonville, Florida

Keystone Heights, Florida

Orlando, Florida(2 reports)

Palm Harbor, Florida

Saint Petersburg, Florida

Sarasota, Florida

West Palm Beach, Florida

Camilla, Georgia

Davenport, Iowa

Ewing, Kentucky

Brentwood, Maryland

Moss Point, Mississippi

Fenton, Missouri

Saint Peters, Missouri

Greensboro, North Carolina

Cincinnati, Ohio

Richmond, Ohio

Vieques, Puerto Rico

Del Rio, Tennessee

Dallas, Texas

Henderson, Texas

Fairmont, West Virginia

show all

Gardeners' Notes:


On Nov 16, 2015, RobertWM from Clawson, MI wrote:

Very likable and accommodating plant. I first got a couple to add some color to the yard and liked it well enough to see if it would overwinter as a house plant. That was maybe eight years ago and now I have several pots of it in both south and east windows. During the very shortest winter days, it grows greener but as soon as the days start to lengthen, it turns wine red again and can be cut back severely to make it bushy again. Some of them go outdoors for the summer, another stays inside year round and it's happy either way. It's a bog plant and likes to be wet but if it wilts from drying out, it springs back to life when watered. One quirk: the white flowers apparently can eject their seed for several inches because it will come up in any pot near it. I occasionally have to pull the se... read more


On Oct 9, 2010, prettyitup from Moss Point, MS wrote:

I'm in Z8. I bought a small one this spring from someone selling plants on the side of the road. He called it Blood Plant. I searched the database here to see if that was actually it's name. I am glad to know it's also called Joy Plant Purple Knight since I hated the name Blood Plant. I love mine. I have it in part shade in front of some Hidden Lillies which are a med. lime green. I don't mind the legginess...the dark burgundy color of the whole plant more than make up for it. My house is pale yellow and I plan to get a pot of cuttings going for the porch. I think it would look awesome.


On Jul 30, 2009, Pillita from Keystone Heights, FL (Zone 8b) wrote:

This is a fantastic plant, extremely heat and drought tolerant, and adding vibrant color to the garden. It overwintered well, both in the greenhouse and heavily mulched in the ground, and reseeds well.


On Nov 17, 2006, JaxFlaGardener from Jacksonville, FL (Zone 8b) wrote:

This is a very adaptable plant for both sun and shade in my garden. It is less likely to be "leggy" in the shade, from my experience with the plant, but as noted above, it can be easily pruned back at any point along the stem with no damage to the plant. I generally just stick the pruned cuttings with no special care nor rooting hormone into the ground around the plant and within a week or so, they are already rooted and I have more plants to share. I've been passing this plant around to friends and all have been happy with it. The most recent experiment with it was to place it in a friend's garden in what I would call deep shade. It is thriving there. Another plus for this plant is that it seems to be drought tolerant. Though it will wilt somewhat if left dry too long, it will reco... read more


On Jul 6, 2006, michaeladenner from Deland, FL wrote:

Very dark burgundy, nearly black ovate leaves and stems. The literature says they grow to 36", but I suspect mine will reach higher by the end of summer. Branching but mostly upright growth. I grew a dozen of these from seeds (Parks) -- very easy propagation. In warm weather, I had nearly 100% seed to garden. I rarely get such a high rate. Not terribly leggy yet, as some have remarked here, but I see the potential. I plan regularly to pinch them back.

I think Purple Knight looks stunning mixed with yellow: Think Dune Sunflowers (Helianthus debilis) and the mounding yellow Lantana; but I imagine any bloom would be enhanced with the burgundy backdrop.

Its cultural requirements: Full sun, slightly improved and well drained soil, low fertilizer and not overly wet... read more


On Oct 22, 2005, Badseed from Hillsboro, OH (Zone 6a) wrote:

This is a delightful plant in zone 6! It is easy from seed, easy from cuttings and low maintenance. This plant can be pruned by snipping right above a set of leaves, to keep it more compact. It lends a definate punch of dark color to any foliage combination. It has worked well for me in full sun and partial shade.


On May 16, 2004, Toxicodendron from Piedmont, MO (Zone 6a) wrote:

I grew this plant last year as a tender perennial planted in both full sun and part shade. It tends to get very leggy in my opinion, with long distances between nodes in spite of pinching back. It is a pretty contrasting color with pinks, especially purple coneflower hybrids like Magnus. I did not care for it enough to keep a piece for this year. Allow plenty of space if you grow it.