Bush into the blue

Paraguay Nightshade

Paraguay Nightshade

A fast-growing shrub with slim arching stems and fragrant blossoms, Paraguay nightshade (also known as blue potato bush) makes a great complement to a mixed border. Count on this easy-to-grow plant to produce brilliant purple flowers with yellow centers from summer well into fall. Deer don’t usually bother it, nor is it plagued by any significant pests or diseases. Even though this plant is closely related to potatoes, eggplants, and tomatoes, it’s also related to deadly nightshade. So don’t eat any part of this shrub—it’s poisonous.

genus name
  • Lycianthes rantonnetii
  • Sun
plant type
  • Shrub
  • 3 to 8 feet
  • To 8 feet wide
flower color
  • Purple
foliage color
  • Blue/Green
season features
  • Fall Bloom,
  • Summer Bloom
problem solvers
  • Deer Resistant,
  • Drought Tolerant
special features
  • Fragrance
  • 9,
  • 10,
  • 11
  • Stem Cuttings

Planting Paraguay Nightshade

Plant Paraguay nightshade with other long-blooming plants to create a garden bed that is alive with color for months at a time. Long-blooming plants like this one also tend to be pollinator magnets. The following plants partner well with Paraguay nightshade and roll out a buffet for bees, butterflies, and hummingbirds: lantana, hibiscus, perennial salvia, and yellow mandevilla (Pentalinon luteum).

Paraguay Nightshade Care

In warm climates this shrub is grown outdoors where it will bloom all year long. The small blue flowers are followed by scarlet berries. In cooler regions, Paraguay nightshade can be grown outside in a container, then brought inside prior to the first frost. Flowers will appear in summer and fall.

Paraguay nightshade grows best in full sun and moist, well-drained soil. It does not tolerate drought well, so make sure it gets about one inch of water a week. More water is necessary during extreme heat. Plant this fast-growing shrub in a location where it can spread. Planting Paraguay nightshade near a patio or outdoor gathering area will make the most of the lovely perfume the flowers add to outdoor spaces. Avoid growing this shrub in areas where children hang out, since they may be tempted to eat its poisonous red berries.

Plant in spring and water well after planting. Continue watering regularly and deeply during the first growing season to encourage plants to develop a deep, extensive root system. Spread a 2-inch-thick layer of mulch around the base of the plant to prevent soil moisture loss. An evergreen plant, Paraguay nightshade provides rich color year-round. Prune it as needed in early fall when flowering slows down, since the flowers grow only on tender young stems. It tolerates shearing well.

Paraguay nightshade can also be planted in a large, deep container. Enjoy its bold purple blooms and delightful fragrance on a sunny patio or deck. Fill the pot with a high-quality potting mix and plan to water daily to ensure its water requirements are met. Mix a slow-release fertilizer into the soil in early spring to supply nutrients through summer.

What Is A Potato Bush: Information About The Blue Potato Bush Plant

The potato bush plant is an attractive shrub that grows up to 6 feet 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.

What is a Potato Bush?

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.

Potato Bush Growing Conditions

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 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.

How to grow Solanum crispum ‘Glasnevin’

It is a vigorous plant and can grow up to 20ft but is easily controlled by pruning in spring. The stems need tying to wires on a fence or wall, but its lax habit adds to its charm and it lends an exotic feel to the garden.

Growing tips

Solanums prefer a neutral to slightly alkaline (limey), well-drained soil in full sun. A high-potash fertiliser in spring will encourage profuse flowers in summer. You will have to tie the young shoots to wires for support or alternatively let the plants scramble through other mature shrubs or grow over a pergola where the beautiful flowers hang down above your head.

To prevent the plants becoming a tangled mass, in spring, prune the flowering shoots from the previous year to two or three buds from the main stems that form the permanent framework of branches. Cut out dead shoots at the same time.

Don’t prune all old growth hard at one time as you may kill the plant. To encourage new growth from the base, cut out one or two old growths every two or three years.

You can propagate by taking semi-ripe cuttings from summer to early autumn. Take cuttings about 3in long with a heel of older wood. Put the cuttings around the edge of small pots of multi-purpose compost, place a polythene bag over them and put on a bright windowsill, but not in direct sunlight.

If you have a propagator, gentle heat will speed the formation of roots. The cuttings should root in about four weeks. Pot up individually, protect from frost over winter and plant out in spring.

Alternatively, propagate by layering. Take a stem and place it on the ground. With a trowel make a slight depression in the soil and bury a part of young growth with the growing tip out of the soil.

Cover the shoot with soil and place a large stone over it to hold the stem in place and in a few months it will form roots. Leave for a year and then dig up and plant out.

Solanums are generally trouble-free, but aphids can sometimes be a problem. All parts of the plant are poisonous and can cause discomfort if eaten.

Good companions

Although ‘Glasnevin’ and other species of solanum can grow quite large, they are well behaved and make wonderful companions for other plants. I have seen them scrambling through evergreen shrubs and mixed with climbing roses.

‘Glasnevin’ looks particularly good with pink roses such as ‘Aloha’. The small white flowers of Solanum laxum ‘Album’ make a wonderful contrast to the purple-blue of ‘Glasnevin’.

Solanums also make good partners for clematis, with the main stems of the solanum making a good support for clematis. Older solanum stems can become bare of shoots and flowers so growing with clematis helps disguise this.

I wouldn’t grow it with Clematis montana and its cultivars as they are too vigorous, but any of the late-flowering clematis hybrids such as ‘Comtesse de Bouchaud’ or species clematis make ideal partners.

The late-flowering hybrids of clematis are pruned hard in spring so these don’t overwhelm the solanum. Other sun-loving climbers, such as jasmine, make good companions. Jasminum officinale ‘Argenteovariegatum’, with white flowers, is one to try.

Buy Solanum crispum ‘Glasnevin’ from the Telegraph Gardenshop.



A refreshing change from common vines, solanum is a shrubby climber with an almost- perpetual flush of petite blossoms. Solanum is grown as an annual in cold regions and hardy in Zones 9 to 11 where it is semi-evergreen. Solanum is also called potato vine (not to be confused with sweet potato vine). Solanum blossoms vary from white to lavender to deep purple. Its small, medium-green foliage makes a good backdrop for its flowers.

genus name
  • Solanum
  • Part Sun,
  • Sun
plant type
  • Annual,
  • Shrub,
  • Vine
  • 1 to 3 feet,
  • 3 to 8 feet,
  • 8 to 20 feet,
  • 20 feet or more
  • 1 to 4 feet
flower color
  • Purple,
  • White
season features
  • Summer Bloom
problem solvers
  • Deer Resistant,
  • Good For Privacy
special features
  • Low Maintenance,
  • Good for Containers
  • 9,
  • 10,
  • 11
  • Seed,
  • Stem Cuttings

Landscape Ideas

Solanum is a versatile vine. Employ it as a living screen. Plant it at the base of a sturdy trellis and it will quickly scramble toward the sky. Grow solanum on a fence or wall and bring the vertical surface to life with flowers and foliage. Many types of solanum are semi-evergreen and will provide interest nearly year-round. Solanum tolerates partial shade, making it useful in the dappled light of a patio. Tie it to a post of an arbor or pergola to encourage it to climb where it will provide additional shade below the structure.

Create a pretty pathway into your garden with this arched arbor.

Companion Plants

Grow solanum with other heat-loving vines such as bougainvillea. The bold colors of this duet add a tropical vibe to a yard. Other great non-vine planting companions include hibiscus, salvia, carpet rose, and lantana. Solanum, like hibiscus, salvia, and bougainvillea, is a favorite stopping point for hummingbirds. Be sure to keep an eye out for these winged visitors and limit chemical use in your landscape to protect the pollinators.

Solanum Care Must-Knows

Solanum grows best in full sun or part shade and moist, well-drained soil. It will tolerate brief periods of drought after it is established. Plan to water solanum regularly for good flowering. It is also a reliable container plant for a porch or patio; just be sure there is a climbing structure nearby.

Solanum grows fast. Prepare for it to climb shortly after planting by placing a trellis nearby or siting it where it can scramble up a fence or pergola. Attach sturdy cables to a fence or wall to give solanum something to twine around and climb up. Gently bend the stems around a pergola or arbor post to encourage climbing.

Fertilize solanum twice during the growing season with an all-purpose fertilizer, following label directions. Where solanum is hardy, prune it in the fall to control its size.

Keep your annuals well-fed using these fertilizing tips.

More Varieties of Solanum

Royal Robe nightshade

Solanum rantonnetii ‘Royal Robe’ bears rich purple fragrant flowers spring to fall on a plant that can reach 8 feet tall. Often grown as an annual, but it’s grown as a shrub in Zones 9-11.


Solanum quitoense offers large, velvety leaves with purple hairs and orange-yellow spines with fragrant white flowers and fuzzy orange fruit. While it’s usually grown as an annual where it grows about 3 feet tall, it is an 8-foot-tall shrub in the tropics.

Lychee tomato

Solanum sisymbriifolium bears large white flowers flushed with silvery blue and edible, bright-red fruits. The leaves and stems are covered in spines. It grows 3 feet tall. Note: In some areas, this plant has become an invasive pest.

Plant Solanum With:

Plant a castor bean and then stand back. This is one of the fastest-growing, giant annuals in the garden, rivaled only perhaps by giant sunflower. By midsummer, you’ll have a huge (it can hit up to 20 feet) tropical plant sporting burgundy foliage. It’s a great plant to grow with kids. Be careful, though. The seeds are extremely toxic.Wait to plant it outdoors after all danger of frost has passed; castor bean hates cool weather and won’t grow well until temperatures heat up in summer.

Elegant, silvery licorice plant is so useful to set off flowers in blue, white, purple, and other colors and to add contrast to plantings where you want more than just a mass of green. It’s especially good in containers, where you can admire it up close and show off its spreading habit to best effect.Technically a tropical shrub, licorice plant is usually grown as an annual in the United States. It does best in full sun and well-drained soil.

Lycianthes, Blue Lycianthes, Blue Potato Bush, Paraguay Nightshade ‘Royal Robe’



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 has been said to grow 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

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