solanum

( soh - LAY - num )

At-A-Glance Information

This genus includes evergreen, deciduous, and semi-evergreen shrubs, vines and perennials. Commonly grown crop plants like potatoes, tomatoes, and eggplants are members of this genus. Solanum shrubs and trees need full sun to partial shade, and moderate to regular water (though this varies by species). All plants have small, star-shaped flowers in blue or white. Some flowers are followed by edible fruits, depending on the species, though most are poisonous. For the Solanum species that are edible, such as Tomato, Potato, and Eggplant, visit the Solanum crop page linked here:

Solanum Species and Varietals

Solanum is the largest genus in the Nightshade family (Solanaceae), with about 1,500 - 2,000 distinct species. The genus was first described by Pliny the Elder, and the name Solanum is most likely a reference to the fact that the plants within the genus are sun-loving. The popular species Solanum rantonnetii (Blue Potato Bush) is now categorized under the genus Lycianthes rantonnetii. Solanum growing zones vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Solanum aviculare (Kangaroo Apple)
This species is an evergreen shrub, best in zones 15-17 and 21-24 and is native from Australia and New Zealand. It quickly grows to 6-10 feet tall and 5-8 feet wide with deep green leaves and purple flowers that bloom in spring and summer. Fruit is scarlet and inedible.

Solanum crispum
This species is an evergreen vine and grows well in zones 8, 9 and 12-24. It is native to Chile and Peru, and climbs to 12 feet and has soft green, wavy-edged leaves. In summer, fragrant lilac-blue flowers bloom in clusters. Fruit is small, yellow and inedible. Great on trellises, against walls, and up posts. In frost conditions, this vine may drop its leaves. Variety 'Glasnevin' has deep blue flowers in larger clusters than the species. 

Solanum laxum (Solanum jasminoides) (Potato Vine)
This species is evergreen or semi-evergreen and grows in zones 8, 9, 12-24, H1 and H2. It is native to Brazil and reaches 30 feet. Flowers are white with tinges of purple, blooming heaviest in springtime, but intermittently all year. Cut back severely at any time of the year to control growth and prevent tangling of vine stems. Runners will grow along the ground; these can be taken off the plant at any time.

Solanum muricatum (Pepino)
This species is best in zones 17, 23, 24 and H2. It is native to Columbia, Chile, and Peru. Reaches 2-3 feet tall and around 4 feet wide. Leaves are bright green and flowers are blue, blooming in spring and early summertime. Fruit is greeish yellow with purple stripes. Fruit tastes like a cross between a melon and a cucumber. Great in hanging baskets. 

Solanum seaforthianum (Brazilian Nightshade)
This species is an evergreen or semi-evergreen vine that grows in zones 16, 21-24, H1 and H2 and reaches 15 feet with support. Leaves are medium green and flowers are violet-blue, appearing in summertime. Fruits are inedible, but enjoyed by birds.

Solanum wendlandii (Costa Rican Nightshade)
This species is a deciduous vine that does best in zones 16, 21-24, H1 and H2. It reaches 15-20 feet and has hooked spines along its vining stems. In summertime, lavender-blue flowers are borne in dense clusters. Great at climbing trees, pergolas, and eaves. Leaves will drop off in cooler temperatures, and spring leaf out is relatively slow.

Solanum xantii
This evergreen shrub is native to California and grows best in zones 7-9, 11, and 14-24. It reaches 2-3 feet tall and 3 feet wide, with green leaves and purple flowers that bloom in late winter and spring. Varieties include 'Mountain Pride' and 'Salmon Creek'; this species needs little to no water.

Caring for and pruning solanum shrubs

Plant your Solanum in a spot that gets full sun (ensure that it gets between 6 and 8 hours of sun per day). Ensure that soil is well-draining, loamy and fertile before planting. Amend soil with organic material for the best performance. Water deeply and regularly, keeping soil consistently moist. Water needs vary depending on the species; make sure to check the specific water needs of your shrub before planting. Pruning also varies depending on the species grown and the purpose of the plant (whether your goal is to harvest fruit or improve the look of an ornamental). Fertilizing these shrubs is simple; edible varieties can benefit from regular feedings with a balanced, slow-release fertilizer. When establishing themselves, some plants may need staking to assist their stems with withstanding wind or holding the weight of fruit or flowers. Vining species will need a structure to cling to.

Propagation

Solanum plants are best propagated using cuttings. To propagate your shrub, tree or vine, follow the instructions below:

Propagating Solanum by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Problems and Pests

Solanum plants are susceptible to a variety of garden pests and diseases, including:
  • Aphids
  • Hornworms
  • Blight
For more information on these issues, see the links below:
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Gallery

Use Solanum shrubs in mixed plantings.
The genus has a wide variety of habits, from shrubs and subshrubs to vines and trees.
Vining species can be used on trellises and are great for espaliers.

Videos

All about Solanum jasminoides.
Learn about growing and harvesting Pepino plants.

Resources

Solanum - Growing Guide
Solanum
Solanum Plant Family: All About the Solanum Genus
Wikipedia: List of Solaum Species
Wikipedia: Solanum
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 605, Solanum
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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