Celtis

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At-A-Glance Information

Commonly referred to as Hackberry or Nettle Tree, this genus of deciduous trees requires full sun to partial shade and moderate water. Fruits will attract birds to the garden. Mature trees have cork-like bark and deep roots, and foliage turns yellow in cooler fall temperatures. These trees can tolerate strong winds and being planted near roads and walkways, and their roots won't cause damage to hardscaped areas. Hackberry can also tolerate desert heat, alkaline soils, and drought and do not need much pruning to take on a handsome shape. Use these low-maintenance trees as street or shade trees or as specimens in the landscape.

celtis Species and Varietals

The genus Celtis is a member of the plant family Cannabaceae and includes between 60 and 70 species. Hackberry growing zones vary depending on the species; for more information consult the descriptions below. To find your zone, click here: Zone Map.

Celtis australis (European Nettle Tree, Mediterranean Hackberry, Lote Tree, Honeyberry, European Hackberry)
This species is native to southern Europe, Asia Minor, and north Africa and reaches between 33 and 82 feet tall when mature. Foliage is green, flowers are white to cream-colored, and fruits are green and mature to black. This species grows best in USDA hardiness zones 6b-9b and is considered invasive in Australia and the southwestern United States.

Celtis caucasica (Caucasian Hackberry, Caucasian Nettle Tree, Mediterranean Hackberry)
Native to the Caucasus, Central Asia, and the western Himalayan region, Caucasian Hackberry performs well in USDA hardiness zones 5-9. These trees are commonly grown as street trees. Their roots are non-invasive, making them perfect candidates for installation near paved areas. Mature trees reach up to 5-65 feet tall with a similar spread.

Celtis julianae (Julian Hackberry, Julian Nettletree, Julian Celtis)
Native to southern and central areas of China, these trees are fast-growing and have greyish bark. Typically, these trees will reach about 60-80 feet tall and 40-75 feet wide. They are used as street trees in many cities in China and France and grow well in USDA hardiness zones 6a-9b.

Celtis koraiensis (Korean Hackberry)
This species is endemic to the Korean Peninsula and northern China. These trees produce cream to white flowers in April to May, followed by fruits that ripen in September and October. Korean Hackberry reaches about 50 feet tall and just as wide when mature. This species performs well in USDA hardiness zones 4-9.

Celtis laevigata (Sugarberry, Sugar Hackberry, Southern Hackberry, Lowland Hackberry, Texas Sugarberry)
These trees are native to the eastern United States over through Texas and northeastern Mexico, where it primarily grows along streambeds and in moist areas. These are attractive landscaping trees that serve as fantastic shade trees and produce sweet berries. They grow well in USDA hardiness zones 5-10.

Celtis occidentalis (Common Hackberry, Sugarberry, Beaverwood, Northern Hackberry, American Hackberry)
This species is best in zones 1-24 and is native to eastern North America. These trees reach 50 feet or taller and have bright green leaves. Common Hackberry has a rounded, somewhat pendulous habit, and does not leaf out until the middle of springtime. This species is resistant to Oak Root Fungus. Variety 'Magnifica' (actually a hybrid between C. laevigata and C. occidentalis) is a great garden variety with dark green leaves and insect pest resistance.

Celtis pallida (Celtis ehrenbergiana) (Desert Hackberry, Granjeno, Spiny Hackberry)
Best in USDA hardiness zones 7-10 or Sunset growing zones 10-13, this species is native to the southwestern United States and northern Mexico. It forms a small shrub or tree with dense foliage and spiny growth reaching 18 feet tall at maturity. Berries are orange and small. This species makes a handsome desert planting for encouraging biodiversity, as a screen or barrier, and is great for erosion control.

Celtis paniculata (Tripewood, Silky Keltis, Silky Celtis, Native Hackberry, Native Celtis, Investigator Tree, Whitewood)
This rainforest-dwelling species is native to Malesia, Melanesia, and Australia. Trees can reach 130 feet tall when mature, and have greyish-brown thin bark. Flowers are green, blooming in December and January, and fruits ripen the following July through March in the tree's native range.

Celtis reticulata (Celtis douglasii) (Western Hackberry, Netleaf Hackberry, Acibuche, Palo Blanco, Douglas Hackberry, Netleaf Sugar Hackberry)
This species grows well in USDA hardiness zones 4-11 or Sunset growing zones 2-24 and is native to Idaho, eastern Washington, northern Oregon through Utah, as well as mountainous areas ranging from Arizona through Southern California. Individual trees reach 25-30 feet tall and wide at maturity, and have pendulous branches and toothed leaves that are whitish underneath.

Celtis sinensis (Chinese Hackberry, Yunnan Hackberry, Japanese Hackberry)
This species is native to East Asia and does best in USDA hardiness zones 5-9 or Sunset growing zones 8-16 and 18-20. It is similar to Celtis occidentalis, but only reaches 40-60 feet tall and about as wide. Leaves are smooth and glossy, and have scalloped edges. These trees are commonly used in traditional eastern Asian landscapes as ornamental shade trees. 'Green Cascade' is a beautiful, weeping form of this species. This species is considered to be invasive in Australia and South Africa.

Celtis tenuifolia (Dwarf Hackberry, Georgia Hackberry)
These trees are native to eastern areas of North America, and are considered threatened with extinction in Canada. They grow well in USDA hardiness zones 4a-9b. These trees are tolerant of drought but not shade and can grow in many different habitats. They are wonderful additions to the landscape for increasing biodiversity in the landscape, as their berries are bird favorites.

Celtis tetranda (Nilgiri Elm, Eastern Nettle Tree, Adava, Garuka)
These trees have a wide native range, including the Indian Subcontinent, southern China, Southeast Asia, and western areas of Indonesia. These trees are occasionally available for purchase through specialty nurseries or commercial growers. They typically reach up to 66 feet tall at maturity.

Caring for celtis

Choose a planting spot in the landscape that is in full sun; these trees can tolerate partial shade as well. Hackberry should get at least 6 hours of direct sun each day. Space trees 15-30 feet apart for best airflow. These trees are adaptable to a wide range of soils, including clay, sand, and loam. As long as soil is well-draining, these trees can tolerate even poor soil conditions that is compacted and infertile. After planting, apply a layer of mulch around the base of the tree to help increase soil moisture retention and suppress weed growth. Newly planted trees should be watered regularly during the first two years after installation. Once established, Hackberry trees are considered to be drought-tolerant, simply needing infrequent deep waterings during prolonged dry weather.

Hackberry trees do not require fertilization; a simple yearly application of compost around the base of the tree is sufficient to supply necessary nutrients. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These trees should be pruned in late winter or early springtime, before new growth pushes out for the year. Simply remove dead, damaged, diseased, or crossing branches to maintain a healthy shape and structure. Make sure to control for weak crotches and competing leaders; Hackberry trees can develop weak branch attachments, leading to breakage in high winds. Regular pruning (about once a year) is recommended to prevent this issue. These trees are considered long-lived perennials, persisting in the landscape for upwards of 100-150 years before needing to be replaced.

Harvesting Celtis (Hackberries)
All species of Hackberry produce edible berries (which share texture characteristics with nuts), though some species do produce fruits that tend to be a little sweeter than others. Species that are commonly cultivated for fruit harvesting include Celtis occidentalis, Celtis laevigata, and Celtis australis. Hackberries are small, hard fruits made of sweet tissue around a hard seed. They are commonly harvested in fall, when the fruits are pea-sized. They will vary in color from dark maroon to orange to brown (depending on the species grown), and can be picked off of trees or branches can be shaken to release the fruits. After harvesting, these fruits can be used in a number of ways. They have a candy-like taste, are sweet and crunchy, and have a flavor reminiscent of date or black tea. Seeds are nutty. They can be boiled down and turned into a sugar syrup, made into a nut milk, or ground up (seeds and all) for mixing with other foods.

Disclaimer: Information contained on this website is strictly and categorically intended as a reference to be used in conjunction with experts in your area. Foraging and consumption of plant parts should never begin without the guidance and approval of a local plant specialist. The providers of this website accept no liability for the use or misuse of information contained in this website.

Propagation

Celtis can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. Propagation of Celtis trees by cutting is somewhat difficult; the cuttings do not always root, and success rate is usually pretty low. To propagate your tree, follow the instructions below:

Propagating Celtis by Cutting

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. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
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.
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.
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.

Propagating Celtis by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a plastic bag or other sealable container, sand, a bowl, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The fruits on Celtis plants are pretty easy to spot, they can be maroon, red, orange, or brown and are left behind after flowers have faded. These fruits can be harvested by hand from their attachments, scavenged from the ground under trees, or branches can be shaken to release them. Once they are off the tree, ferment them for three days in a bowl of warm water to release the skin and pulp from the seed itself. Remove and rinse seeds after fermenting, and lay them out.
Celtis seeds must be cold-stratified before planting to mimic the natural processes that lead to germination. Place seeds in a plastic bag or other sealable container filled with moistened sand and bury them a bit in the substrate. Place the container into the refrigerator or other space that stays between 38 and 41 degrees Fahrenheit. Leave seeds for between 60 and 90 days, and then remove them from their sandy bed.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a half inch to an inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 60 to 90 days from sowing.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. 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 (after the danger of frost has passed), when you can transplant it to its new home.