Castanea

( kass - tan - EE - uh )

At-A-Glance Information

Commonly called Chestnut, this genus of deciduous trees needs full sun and regular water to perform well in the landscape. Chestnut trees are commonly used as shade trees, though they do need to be placed where their pollen's scent won't disturb the noses of passers-by. Leaves are green and flowers appear in creamy white in catkins in summertime. These trees are native to temperate regions of the Northern Hemisphere, and grow at a moderate rate, taking about 20 years to reach full size. Chestnut trees are excellent shade or lawn trees, and look great in natural, rural, and urban landscapes.

Castanea Species and Varietals

The genus Castanea includes 8 species and is a member of the plant family Fagaceae, making them relatives of Oaks and Beeches. The best growing zones for Chestnut trees are USDA hardiness zones 4-9 or Sunset growing zones 2-9 and 14-17, though this varies somewhat depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Castanea crenata (Japanese Chestnut, Korean Chestnut)
Native to Japan and Korea, this species of Chestnut is resistant to Ink Disease. This is a medium-sized deciduous tree that reaches between 30 and 50 feet tall at maturity. Flowers bloom in summer and fall, and nuts are ready for harvest by October. Fruits have a sweet flavor to them. This species grows well in USDA hardiness zones 4-8. Resistant to Chestnut Blight Fungus.

Castanea dentata (American Chestnut)
This large deciduous fast-growing tree is native to eastern North America, and has prolific edible nuts. Maximum height of these trees is 115 feet, and they produce green foliage and cream-white flowers in June and July. These trees were decimated in their native range by an invasive fungal disease, Chestnut Blight. These trees grow well in USDA zones 4-8.

Castanea henryi (Henry's Chestnut, Chinese Chinquapin, Pearl Chestnut)
These trees reach about 100 feet tall at maturity (closer to 66-82 feet tall in gardens), and is native to south-central and southeastern China, where it is widely cultivated for its edible nuts that are a bit smaller than other species'. Henry's Chestnut grows well in USDA hardiness zones 5-9 and is hardy down to -20 degrees Fahrenheit.

Castanea spp. Hybrids (Hybrid Chestnut Tree)
This group of Chestnuts grow best in USDA hardiness zones 4-9 or Sunset growing zones 2-9 and 14-24 and reach 40-60 feet tall and just as wide at maturity. These trees not tolerate alkaline soils well, but do resist Chestnut Blight (in select varieties). Cultivars are outlined below:

'Colossal'
This variety produces great nuts.

'Bouche de Betizac'
A French cultivar that produces large to very large chestnuts.

'Dunstan'
Resistant to blight.

'Nevada'
Small nuts, great cross-pollinizer with 'Colossal'.

'Precoce Migoule'
This European/Japanese hybrid species produces an early crop.

'Skioka'
Produces abundant small nuts, does not cross-pollinate.

'Sleeping Giant'
Sweet, large nuts with blight resistance.

Castanea mollissima (Chinese Chestnut)
This species is native to China, Korea and Taiwan and reaches 35-40 feet tall with a rounded top. The canopy can spread to 20-25 feet wide. Resistant to chestnut blight, but intolerant of alkaline soils. Leaves have edges that are coarsely toothed. These trees produce prolific harvests of nuts. Popularly cultivated varieties with large nuts include 'Kuling', 'Meiling', and 'Nanking'. This species is considered invasive in some areas of the United States, including pars of North Carolina and the Mid-Atlantic region.

Castanea ozarkensis (Castanea pumila var. ozarkensis) (Ozark Chinquapin, Ozark Chestnut, Ozark Chinkapin)
This species of tree is native to the United States, and was first described by William Willard Ashe in 1923. These trees are found growing naturally in the Ozark Mountains in Missouri, Arkansas, Texas, Louisiana, and Oklahoma. This species forms a small tree or shrub, reaching about 40-60 feet at maturity and grows well in USDA hardiness zones 5-9.

Castanea pumila (Allegheny Chinquapin, American Chinquapin, Dwarf Chestnut)
Native to the southeastern United States, this species grows naturally in dry, sandy or rocky uplands in full sun to partial shade. These plants can take the form of a small tree or a multi-trunked large shrub, and have grey-brown bark. They reach between 6 and 26 feet at maturity. This species does well in USDA hardiness zones 5-9.

Castanea sativa (Sweet Chestnut, Spanish Chestnut, Chestnut)
This species is native to southern Europe, northern Africa, and western Asia. It typically reaches 40-60 feet tall in gardens and has toothed leaves. This tree produces the widely sold chestnuts that are found in markets. Susceptible to Chestnut Blight, but resistant to Oak Root Fungus. Cultivar 'Variegata' ('Aureomarginata') has green and white variegated leaves. Sweet Chestnut trees grow well in USDA hardiness zones 5-9, and are considered invasive in the Canary Islands.

Castanea seguinii (Seguin's Chestnut, Chinese Chinquapin, Mao Li, Seguin Chestnut)
These small trees or shrubs have a maximum height of 40 feet tall, and are native to south-central and southeast China. Foliage is green, and nuts produced are about 3-4 inch in diameter. These plants flower in May through July, and produce their fruits in September through November. Best in USDA hardiness zones 5-9.

Caring for Castanea

Chestnut trees require full sun exposure (between 6 and 8 hours of sun per day). This will ensure healthy overall growth and nut production. Ensure that trees have enough space to grow; if they are too crowded they have a tendency to develop fungal issues. Typically, they should be planted around 25-30 feet apart for best airflow. They prefer soil that is well-draining and slightly acidic (with a pH of between 5.5 and 6.5). They can tolerate sandy, loamy, and even slightly rocky soils, but good drainage is essential to tree health. If soil is clayey, consider amending with organic matter or sand to increase drainage. Apply mulch to the top of soil around the base of the tree after installation. This will suppress weed growth, maintain a good soil moisture level, and assist in managing soil temperature.

Water young trees regularly to assist them in developing a strong root system. Once mature, these trees are relatively drought-tolerant, but will still benefit from occasional deep waterings, especially during the drier months of the year. Pruning is minimal on these trees. Simply remove dead, diseased, or damaged branches in late winter or early springtime. Younger trees should be pruned to establish a central, strong leader and a more balanced branching structure. This will help to support the weight of the nuts when the tree matures and begins to produce full harvests. Castanea trees will last for hundreds of years in the landscape if properly cared for.

Harvesting Castanea
When growing these trees for harvesting nuts, it is essential that trees have a mate to cross-pollinate within 100 feet. There are some self-fruitful varieties that will not need a partner. Trees typically begin producing nuts after 3 to 7 years of being in the ground, depending on climate and growing conditions. Nut production increases as trees mature. Chestnuts are harvested in fall, after the nuts begin to drop from the tree. Collect them as soon as possible from the ground to avoid them being eaten by wildlife or spoiling (checking the ground every two days is recommended). After collecting, remove the outer shell to access seeds. Take care when gathering fruits, as the outer shells have sharp spines.

Chestnuts are bitter when raw, and shells are difficult to remove. Take care when consuming unroasted chestnuts, as it can be dangerous for some individuals (those with liver or kidney problems) due to their tannic acid content. Roasted chestnuts are buttery, soft and sweet, reminiscent of the taste of a sweet potato. To roast chestnuts, slit them and soak overnight. Then roast them at 350 degrees Fahrenheit for between 30 and 35 minutes. Allow them to cool down a bit, and shell them while they're still warm. These nuts can also be boiled, and have a sweeter taste when prepared this way. Boiled nuts are commonly used as an additive in pasta sauces or to make paté. Soak nuts in boiling water for about an hour, and then cut the skin open to remove the edible flesh inside.

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

Castanea trees 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. To propagate your Chestnut tree, follow the instructions below:

Propagating Castanea 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 tree.

Propagating Castanea 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 paper bag, 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. When flowers are pollinated, Castanea trees produce fruits that will begin to open up over time and reveal their contents. Typically, this will happen in fall. Collect fruits from the tree or pick them up off of the ground.
Castanea seeds need to be cold-stratified before sowing. To do so, place seeds in a plastic bag or other sealable container filled with moistened sand or sphagnum moss. Place the container in the refrigerator, and leave for about three months' time. After this period has passed, remove the container from the refrigerator and lay them out.
Water the 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 quarter inch to a half-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 3-6 weeks 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.