By: Jackie Carroll
The potato bush plant is an attractive shrub that grows up to 6 feet (2 m.) tall and wide. It is evergreen in warm climates, and its dense growth habit makes it suitable for use as a hedge or screen. You can also grow it as a tree by removing the lower branches. Pinching the tips of new growth encourages bushiness.
The potato bush plant (Lycianthes rantonnetii), a native of Argentina and Paraguay, is best suited to the frost-free climates found in U.S. Department of Agriculture plant hardiness zones 10 and higher. A member of the Solanum family, it is closely related to potatoes, tomatoes, and eggplants, but you should never eat it because it is poisonous. Common names for this plant include blue potato bush, Paraguay nightshade, and blue solanum shrub.
Potato bush plant is grown outdoors in warm climates. In areas with cool winters, grow it as a potted plant that can be brought indoors when frost threatens. In cool areas, an abundance of small, blue flowers bloom in summer and fall. In frost-free areas, it blooms year round. The flowers are followed by bright red berries.
Blue potato bush needs a sunny location and a frost-free climate. The plant prefers an organically rich soil that is constantly moist, but well-drained. Achieve the right balance of moisture by watering the plant slowly and deeply when the surface feels dry. Apply a layer of mulch over the soil to slow water evaporation. If the soil drains too quickly, work in some organic material, such as compost.
Potato bushes grow best if fertilized regularly. You can use a 2-inch (5 cm.) layer of compost once or twice a year; a complete, balanced, slow-release fertilizer in spring and late summer; or a liquid fertilizer once every month or two. Compost helps the soil manage water efficiently.
Avoid growing a blue potato bush in areas where children play, as they may be tempted to put the bright red berries in their mouths.
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When I bought it, it had great purple flowers on it. Since I've moved it indoors for the winter (it's in a big pot), the flowers have disappeared. I water the plant every 2-3 days and it gets about 5 hours direct sun a day. Any ideas? I'd like to see the purple flowers again!
If only every questioner supplied a website with a photo of the plant! A couple possibilities about lack of bloom come to mind:
First, moving plants indoors from outdoors can be a real shock to their system because the conditions are usually so different. Plants may respond by yellowing and dropping leaves, reducing flowering, or going dormant. Don't fertilize for a month or so, but continue watering. In spring, slowly acclimate your plant to moving back outdoors by putting it outside in a sheltered location for a couple hours at a time, gradually increasing the time period. In fall, do that in reverse, rather than abruptly moving from outside to inside, which will help lessen the shock.
Second, almost all plants have a dormant period when they don't produce flowers. Your plant blooms most vigorously during warm weather, although they can bloom almost year around. I suspect that once your plant adjusts to being indoors it will start flowering again.
Finally, plants need phosphorous to bloom. You probably noticed that fertilizers have 3 numbers on the container. These numbers refer to the percentage of nitrogen (N), phosphorous (P), and potassium (K) in the fertilizer. These 3 elements are referred to as macronutrients because plants need them in fairly large (i.e., macro) amounts to thrive. How these elements interact is complicated but in general terms, nitrogen produces lush green growth, phosphorous helps strengthen stems and produce flowers (and eventually fruit), and potassium keeps the root system healthy. If you're applying fertilizer to fruiting (e.g., tomatoes) or flowering plants, you're not as interested in the plant developing leaves as you are in it flowers and fruit, so you'd use a formulation lower in nitrogen and higher in phosphorous, such as Miracle-Gro's Plant Food at 15-30-15. Bone meal is an organic source of phosphorous. After you plant adjusts to the indoors, start a regular fertilizing program. Potted plant roots can't seek out additional nutrients from surrounding soil.
Here's some organic sources of NPK if you prefer.
Nitrogen: alfalfa meal, blood meal, coffee grounds, cottonseed meal, fish emulsion, seabird guano.
Phosphorous: bone meal, rock phosphate
Potassium: greensand, seaweed, kelp
Be careful not to overwater. Always check the soil before you water and water only if it feels dry a couple inches below the surface. A slow, deep infrequent watering better than frequent light watering. Leach salts at least once a month by letting water run through the pot.
The blue potato bush is a perennial evergreen shrub. It is a tropical plant and very heat-tolerant, but can survive in cooler climates as well. Its showy flowers and berries make it a good choice for an ornamental bush. Seeds from the bush are poisonous, and no part of the plant should be ingested.
Blue potato bushes are native to Paraguay and Argentina. They are sometimes also called Paraguay nightshade because of their origins. Blue solanum shrub is another name for the plant. Its scientific categorization is Lycianthes rantonnetii. Blue potato bushes belong to the Solanum family. Biologists classfiy the common potato, Solanum tuberosum, which is in the same family.
These shrubs can grow up to 8 feet (2.4 meters) tall and can spread as much as 6 feet (1.8 meters) wide. They are typically very bushy, with many branches. The plants can also be pruned and trained to grow as small trees.
The evergreen leaves of the blue potato bush are medium to dark green. They can be up to 4 inches (10 centimeters) long, and are usually oval-shaped and somewhat pointed. The leaves usually also have wavy edges.
As the name implies, the blue potato bush produces dark blue or violet flowers that grow in clusters. The centers of these blooms are light blue or yellow. The flowers are round and usually 0.5 to 1 inch (1.25 to 2.5 centimeters) in diameter. The shrubs flower in summer and fall in more temperate climates, but where it is warm enough they will bloom year-round. Berries from the plants are red, oval, and up to 1-inch (2.5 centimeters) long.
The blue potato bush has several different varieties, which have slight variations in their flowers and leaves. The Royal Robe potato bush has darker, bluish-purple flowers, while the Outremer has wider flowers that are a more pure blue color. Variegata Aurea, as the name implies, is a variety that has variegated leaves.
Being from tropical climates, the blue potato bush requires constantly moist soil, but they should not be watered too frequently. The plants prefer neutral or slightly acidic soils with lots of organic matter, and should be planted in full sunlight. They can withstand temperatures down to 15°F (-9.4°C), although they should be protected from frosts. In colder climates, the shrubs act like deciduous plants, freezing in the winter but growing again once temperatures warm in the spring.
Why blue potatoes? Why not? First, THIS is what potatoes looked like originally, when first used for food about 10,000 years ago. Their blue color gives them the antioxidant power of kale and spinach and—let’s face it—they taste better and are fun to eat. Grow these blue heirloom beauties—or, find them in your market!
I planted my first All Blue potato back in 1990. I’ve been hooked ever since. Who doesn’t love to mash blue potatoes?
As a kid, I hated potatoes. My Mom cooked mashed potatoes with the consistency of wallpaper paste. Adulthood wasn’t much better I even avoided French fries. Children changed the equation I needed to set a positive example. A seed catalog arrived one spring with photos of vivid blue-skinned potatoes. The flesh was blue, too. I thought my son would eat them out of curiosity. I was really projecting my own potato problems, because he already was a French fry and baked potato fan.
Blue and purple pigments developed as mechanisms to shield tubers from excessive levels of ultra violet light found at high altitudes. Tubers exposed to direct sunlight turns green, which indicates large amounts of solanine, a compound that sickens humans. All potatoes contain tiny amounts of solanine, but green portions contain toxic amounts. The first potatoes grew in crevices and rocky outcroppings where the soil is very shallow. Developing tubers had only a scant layer of dirt to cover them, so purple and blue pigments evolved over time as a natural sunshade.
Any potato is easy to grow, and All Blues are even easier, as they seem to resist fungal diseases. I place tubers on top of a garden bed that has been enriched with compost and a bit of soil sulfur. Potatoes develop scab in alkaline soils (6.0 to 6.5 pH is ideal), and my ground is 7.2 pH. So I add sulfur to acidify the soil. I use whole tubers, instead of cutting them into chunks, as many gardeners do. I feel I’m avoiding a rot problem, as early spring in my area is cold and wet.
All Blue is just one of the heirloom potatoes I grow. Red Cranberry and Russian Banana Fingerling are both as colorful and tasty.
After spacing the potatoes about 12 inches apart in every direction, I cover the bed with about a foot of straw. That’s all I do. Other easy techniques are to grow potatoes in a wire cage above the ground or in grow bags.
You can start harvesting baby or “new” potatoes when plants flower. And, yes, their flowers are blue, too!
What do you think about the All Blue Potato? Please share your comments—and any questions—by posting below!
Edible potatoes may sometimes be called bushes but they are in fact a perennial vine grown as an annual in the vegetable garden. Two very decorative plants that really are bushes are much larger and another potato bush is an Australian native. Gardeners in warm climates may be able to grow all of these plants.
Although some of these are solanums, they have distinct differences as well as similarities:
Potatoes are native to South America and have been taken all over the world. In many countries, they form a large part of the diet. Cool-season tubers, potatoes will grow in any USDA Zone if planted at the proper time. They prefer acidic, well, drained and fertile soil. They don’t require complicated care and can be stored for months under the right conditions.
Lycianthes rantonnetii is a native of Argentina and Paraguay. Evergreen in warm climates, it is hardy in USDA Zones 10 and above. Although closely related to tomatoes and potatoes, it is poisonous and should not be eaten. The attractive blue flowers bloom in summer and fall and are followed by bright red berries. Growing up to six feet in height, it can make a good hedge.
Solanum ellipticum is native to Australia. Also related to members of the nightshade family, like eggplants, tomatoes and the edible potato, it is a small fruiting shrub. The fruit has a slightly pungent odor and is typically produced after a fire or rain. The fruits are edible both raw and cooked. This plant does better in warm climates.
Another solanum, Solanum crispum ‘Glasnevin,’ is grown in USDA Zones 8 through 11. It is hardy and evergreen, unlike edible potatoes which will die back in a hard frost. It can be grown as a free-standing shrub or trained to an espalier or trellis. The flowers are blue, with yellow centers, and appear from March to late November. Fruits are inedible.
All of these plants prefer full sun. They need regular water and in warm dry areas may need to be watered frequently to keep the soil moist. Blue potato bush and Chilean potato bush are both tall plants and need deeper soils and higher fertility than the bush tomato. Provide a thick organic mulch and twice yearly applications of a complete, balanced slow-release fertilizer.
|Family:||Solanaceae (so-lan-AY-see-ee) (Info)|
|Genus:||Lycianthes (lish-ee-AN-theez) (Info)|
Tropicals and Tender Perennials
Average Water Needs Water regularly do not overwater
Requires consistently moist soil do not let dry out between waterings
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
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)
Seed is poisonous if ingested
All parts of plant are poisonous if ingested
From semi-hardwood cuttings
This plant is said to grow outdoors in the following regions:
Lemoore Station, California
Manhattan Beach, California
Rancho Cucamonga, California
Willow Grove, Pennsylvania
Darlington, South Carolina
On Apr 4, 2016, Digdeeper from Saint Petersburg, FL (Zone 10a) wrote:
I grew this plant successfully in Alton, Illinois for several years. I brought it in in the winter. It was lovely. I now live in St. Petersburg, FL and have not been able to find the plant.
On Apr 22, 2014, victoria07 from Pawleys Island, SC wrote:
I found this plant was available in CT when we lived there. We have since moved to SC and I have not been able to find it and the nursery here have never heard of it. Any idea where I can buy one? They are hard to describe but I remember them as a vibrant purple/blue.
On Jun 8, 2011, Bazuhi from Downers Grove, IL (Zone 5a) wrote:
Loved this plant!! Found it at Home Depot in 2010 and bought it. I stuck it in a huge pot out in my yard and it grew great.. full sun and of course watered when dry.. when winter came I brought it in to over winter but due to not having enough light it passed away. If I can find this plant this year I have solved that problem with over wintering any outdoor plant. So far no luck.
On Jan 22, 2011, Fortuna from Gilroy, CA wrote:
I planted my potatoe shrub 14 years ago. I live in Gilroy, Ca. and I get a good frost every year. The shrub has grown to over 10 feet tall and just as wide! It bloomes from March to December. Each winter it looses most of its leaves but not all. Today I took a big step and cut it back to 3 feet tall. It was very large and it shaded my vegetable garden during the summer. I feel bad because the humming birds and the robins love it and nested in it each year. The big bumble bees also love it! But. it will grow back it always has, and I have other trees for them to nest in. My English pointer chews on the wood from the shrub. He loves it and he has never been sick from it. My neighbor has been trying to get hers to grow as big as mine. But she has not been successful. It must be a different. read more variety. If I had to I would plant another one!
On Oct 16, 2010, Beelover from Santa Cruz, CA wrote:
I live in Santa Cruz CA Zone 9 and have very well established blue potato shrubs. I have to constantly cut them back because they get higher than my one story home.They pretty much stay put, unlike the Passion Vine which plants itself everywhere. I don't bother to water them so if they like water they must be getting it from the watering of other things in the garden. When not by my house I don't clip them and the birds sit on them and also come and take off the size of stick they need for their nests which means they can get material for their nests without having to go to the ground where cats can get them. The birds and hummingbirds love them and find something edible about the flowers. It is definitely a shrub for wildlife and wildlife lovers. I have them in front of windows on the w. read more est side and they absorb the sunlight.
On May 20, 2010, magicmistic from Mentone, CA wrote:
I agree with nunquam in Davis. This bush grows out of control here in Southern California. I'm planning to hack it into submission sometime soon. Is there a right or wrong time to prune, since this one is blooming constantly here?
On Dec 21, 2009, artbytes from San Diego, CA wrote:
Planted in June. Having problems. The leaves turn yellow and fall off the branches. I'm having a hard time deciding if they are getting too much water or too little water - or what the problem is. They just get worse and worse. Does anyone know how to tell the difference between a plants reaction to too little water or too much water? Thanks.
On Apr 10, 2007, mariner from Casa Grande, AZ wrote:
I put this bush in my landscape two years ago and it was very leggy and sparse the first year. Last winter we had two weeks of very cold weather which nipped it back to a stump and this seems to be just what it needed. In the last month it has shot up quickly and has several blooms, although these are only around the bottom six inches of the bush. I read a note that said that it is poisonous, but that doesn't keep the rabbits from chowing down.
On Mar 5, 2005, Dondi from Ceres, CA wrote:
I am looking to relocate my potato bush and was wondering if anyone had done this and had success
On Oct 3, 2004, xoxokristinoxox from Fort Wayne, IN wrote:
Just bought the "bush." However, mine has been trimmed to resemble a tree. Is not in bloom, but I got it for only $5 at Lowe's on discount. Since I am in zone 5, I am confident it will not survive outside. I was planning on having it as an indoor plant. Will this work?
On Apr 8, 2004, jkom51 from Oakland, CA (Zone 9b) wrote:
I was visiting a friend and saw the most amazing specimen of this rather ordinary plant. Looks like it has actually grown into a substantial tree! I will try to take a picture of it next time I'm in the area. Imagine it must be at least several decades old, this suburb is only about 40 or 50 yrs old at most. It had very handsome, rugged dark bark and was in full bloom, in a sunny site in San Pablo (Northern CA, East Bay/San Francisco Bay Area), CA.
On Feb 10, 2003, nunquam from Davis, CA (Zone 9b) wrote:
The brilliant purple-ish flowers are lovely and very eye-catching. Blooms almost year-round, though only a smattering of flowers during the coldest months of the year (zone 9b).
When considering this plant for the garden, keep in mind that once established outside, it grows remarkably quickly during spring-summer-fall and can become unruly in no time at all. You will need to be aggressive with pruning. Growth stalls immediately after first cold snap and restarts as days get warmer. Mine has attracted clouds of tiny, white, aphid-like insects in summer months.
On Aug 31, 2002, JJsgarden from Northern Piedmont, NC (Zone 7b) wrote:
The Blue Potato Bush has performed excellent for me this year as a container grown plant.. It has bloomed continuously from spring thru summer with dozens of beautiful blooms. Since it is not supposedly winter hardy in my USDA zone 7, I will over-winter it inside.
On Aug 26, 2002, smiln32 from Oklahoma City, OK (Zone 7a) wrote:
Prefers full sun. Grows quickly. In severe cold leaves drop and branch tips may die back. Prune to keep neat. Can be used in tailored landscape areas.
On May 16, 2002, poppysue from Westbrook, ME (Zone 5a) wrote:
This tropical shrub can be grown as a large container speciman. In summer and autumn it bears clusters of 1-inch dark blue to violet-purple flowers with yellow centers. Winter in a cool location and leave almost dry. In late March bring into brighter light and begin to water at regular intervals.
This is a member of the nightshade family and all parts of the plant are toxic. Flowers are followed by red berries so beware of small children that may be tempted to taste them.