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Interesting Facts

There are 1,400 known species of Solanum spread throughout the world. The fruits of S. capsicastrum and S. pseudocapsicum are especially toxic to humans, and will cause severe stomach upset if ingested.

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Blue Potato Bush   Royal Robe (Solanum rantonnetii)

The Blue Potato Bush bears deep purple, slightly fragrant flowers in summer that gives rise to red fruit.  Like many other plants in the Nightshade family, the Blue Potato Bush is poisonous if ingested.

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Plant Types: Perennial, Shrub
Light: Full Sun
Height: 3 feet to 6 feet
Width: 3 feet to 6 feet
Zones: 12a to 15b
Bloom Color: Purple, Yellow
Bloom Seasons: Early summer, Mid summer, Late summer, Early fall, Mid fall, Late fall
Leaf Color: Green
Special Features: All or parts of this plant are poisonous, Not North American native
Fertilizer: Miracle-Gro® Water Soluble All Purpose Plant Food
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Plant Care

Sow seeds indoors 6-10 weeks before last frost, germinates in 1-2 weeks at 65-70°F. Transplant once the soil is 60F and weather has settled.

Plant Growth:

The species of Solanum determines what type of growth you can expect.  Tomato's and the potato have similar looking plant growth.  Both are annual vegetables with green fleshy stems and leaves with small flowers that will bloom through out the growing season.  Some species also grow like vines and either produce no fruit or some that is very poor for eating.  Depending on species, vines in the Solanum genus can either be annual or semi perennial depending on the zone where growing occurs.  Blue Potato Bush is a semi woody, shrub like plant grown for it's semi fragrant blue flowers.  Plant parts of most species of Solanum are quite poisonous.  Only the fruit's of Tomato, Potato and Eggplant can be consumed.  Other species fruit should be avoided.  Winter Cherry produces small round poisonous fruits that should never be eaten. 

Soil and Irrigation:

Average to rich, well-drained soil that remains evenly moist. Neutral to slightly alkaline is best. Water regularly during growing season.


Implement a balanced liquid fertilizer on a monthly basis during the growing season. For S. capsicastrum and S. pseudocapsicum, apply a high-potash liquid fertilizer biweekly until fruit ripens.


Aphids and thrips. Other issues include late blight, powdery mildew, damping off, early blight, gray mold, virus diseases, stem rot and blight.