Lycianthes, Blue Lycianthes, Blue Potato Bush, Paraguay Nightshade 'Royal Robe'

Lycianthes rantonnei

Family: Solanaceae (so-lan-AY-see-ee) (Info)
Genus: Lycianthes (lish-ee-AN-theez) (Info)
Species: rantonnei
Cultivar: Royal Robe
Synonym:Lycianthes rantonnetii
Synonym:Solanum rantonnetii



Tropicals and Tender Perennials

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun

Sun to Partial Shade



Foliage Color:

Unknown - Tell us


4-6 ft. (1.2-1.8 m)

6-8 ft. (1.8-2.4 m)

8-10 ft. (2.4-3 m)

10-12 ft. (3-3.6 m)


36-48 in. (90-120 cm)


USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

USDA Zone 11: above 4.5 C (40 F)

Where to Grow:

Unknown - Tell us


Seed is poisonous if ingested

All parts of plant are poisonous if ingested

Bloom Color:


Medium Purple

Bloom Characteristics:

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

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Spring

Late Spring/Early Summer

Mid Summer

Late Summer/Early Fall

Mid Fall

Other details:

Unknown - Tell us

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

7.9 to 8.5 (alkaline)

Patent Information:


Propagation Methods:

From semi-hardwood cuttings

Seed Collecting:

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed


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

Cullman, Alabama

Kingman, Arizona

Mesa, Arizona

Phoenix, Arizona(2 reports)

Sun City West, Arizona

Surprise, Arizona

Alameda, California

Amesti, California

Antelope, California

Berkeley, California

Clovis, California

Concord, California

Corralitos, California

Dana Point, California

Elkhorn, California

Fallbrook, California(5 reports)

Garden Grove, California

Hanford, California

Interlaken, California

Irvine, California

Long Beach, California

Manhattan Beach, California(2 reports)

Ojai, California

Pajaro, California

Palm Springs, California

Pittsburg, California

Rocklin, California

Sacramento, California

San Diego, California(2 reports)

San Francisco, California

San Leandro, California

Watsonville, California

Winchester, California

Yorba Linda, California

Fort Pierce, Florida

Keystone Heights, Florida

Longwood, Florida

Naples, Florida

Palm Bay, Florida

Tampa, Florida

Braselton, Georgia

Kurtistown, Hawaii

Lexington, Kentucky

Las Vegas, Nevada

Leonardo, New Jersey

Newport, North Carolina

Liberty, South Carolina

Summerville, South Carolina

Fort Worth, Texas

Houston, Texas

Lubbock, Texas

Rowlett, Texas

San Antonio, Texas

show all

Gardeners' Notes:


On Jan 26, 2012, DaleTheGardener from Tampa, FL (Zone 10a) wrote:

I have grown Lycianthes rantonnetii for years. It is very easy, trouble free. Low water needs once established. Prefers clay soil, in sandy soil it doesn't bloom as well (unless you add lime).

Great container plant.

I have grown it in Zone 8b (Austin TX, Lake Travis area) were it freezes back to the ground in most winters. It returns in the spring and blooms early summer until frost.

It should be more widely planted.

It is very easy from cuttings.


On May 14, 2008, isaandhos from Tyringham, MA wrote:

I have potted up two of these plants and plan to keep them outside for the summer.


On Mar 27, 2008, jakthelad from Las Vegas, NV wrote:

I am in Las vegas and have a VERY harsh winter and a VERy hot summer. It died back in the winter to absolutely nothing and frankly, I was too lazy to pull it out thinking it was dead. This spring, it was the first to sprout and it'sa doing well already with flowers almost immediately. I love the colour of the blooms and am thrilled that it has come back.


On Mar 22, 2008, msteri from Buena Park, CA wrote:

Bought this plant yesterday afternoon at WalMart, Garden Grove, California - was a little concerned since most of their plants had extremely dry soil. I watered mine as soon as I got home. Last night I freaked out when all the flowers were gone!! This morning they're all open again and beautiful. Whew!!
Now that I've read all your comments, I hope I can control it's size.


On Mar 18, 2008, MJ_ from Palm Springs, CA wrote:

This morning I found this plant at Lowes in Palm Spring, CA. I'm looking forward to trying it here. Very pretty coloring.


On Sep 23, 2007, mephitis from Lexington, KY wrote:

I read that all parts of this plant are poisonous if ingested. I didn't know that when I bought it but my cats and it have lived happily together all summer.


On Dec 11, 2006, Socalguy wrote:

I live in San Diego,CA and have 5 of these plants. They adapt to the climate here in Southern California as if they are native here. They grow very fast and love the 360 days of sunshine here a year. When planted here they spread like a weed very quickly. They are a very enchanting plant. I love em.


On Feb 5, 2006, gardening4ever from Summerville, SC wrote:

I planted 3 of these plants (quart size) last spring. They grew to a little more than 3 feet tall. All of them have already begun to put on new growth as of Feb. 5, 2006. I plan to move two of them to a more sunny area. This plant seems to bloom better with a little more sun than shade at least in Summerville, SC.


On Aug 30, 2005, frnimay from Clovis, CA wrote:

i live in the california valley and the blue potatoe vine (shrub) dies back in the winter its best if you protect it from freezing.
it loves full sun. i had one at my old home and it is now like a small have to keep the suckers pruned or it becomes a can cut small flowering limbs and put in a vase.mine is now about 8 or 9 feet tall.also it was trained and staked because the main trunk is not thick enough to support it..i love its blooms , and i plan to put another one on the opposite side of my apt. yard.


On Mar 7, 2005, beclu727 from Dacula, GA (Zone 7b) wrote:

My DH bought me this plant for Mother's day last year. It was in a gallon pot. I transplanted to a 14" container and it grew to about 3 ft. It has overwintered in the garage and still has flowers!


On Mar 6, 2005, lilpeanut from Phoenix, AZ wrote:

This beautiful bush bloomed all year in phoenix but better in the spring and summer. I trained it as a vine but it reached over 12 feet untill pruned, looking more like a tree. Very forgiving when not watered regularly. Nancy


On May 6, 2004, cblankenship from King, NC wrote:

I found this plant at the Lowes Home Improvement in Winston-Salem, N.C. on university pkwy.


On Mar 24, 2004, tcross wrote:

I found this plant today at Wal-Mart in Stillwater, OK.


On Jan 21, 2004, patwaters wrote:

I grew this plant in my front yard a few summers ago. It bloomed vigorously all summer with small but noticable violet-blue flowers. The bush was about 5-6 foot high and about the same in width. We (Atlanta, Ga. ) area had a particularly cold winter that year and it was killed back to the groung level and did not reappear next year. I have been trying to fine it since. I have checked most of my local nurseries and mail order sources to no avail, however. I would appreciate anyone telling me where I might find this plant.