Why Plant Chestnut Trees
This is a question that you have to answer before deciding what to buy. From the following list, choose one or two categories that best fit your intentions. Under each category is a list of options and recommendations.
A. Reforestation and timber. The only species that have timber-type growth are the American chestnut and some European chestnuts. Both of these species are susceptible to chestnut blight, and the European is usually not very cold-hardy. At the present time, there are no chestnuts available for large-scale timber plantings in eastern North America. However, progress is being made toward breeding blight-resistant “American”-type chestnut trees, most notably by The American Chestnut Foundation and other groups. We do have a few timber-type hybrids that seem to have adequate blight resistance. We offer seedlings from these, suggested only for small-scale experimental plantings.
If you want to see and grow some pure American chestnut trees (Castanea dentata), send us an e-mail. Even though they are blight susceptible, they often get big enough to bear a few crops of seed before they succumb to blight. We work closely with the American Chestnut Foundation and will be able to help you obtain trees or information. Visit the American Chestnut Foundation’s website at www.acf.org.
B. Wildlife and conservation. For wildlife or open-field plantings (e.g., strip mine reclamation) the best choices are Allegheny chinkapin or Chinese chestnut seedlings. The chinkapin is a native North American shrub or small tree that is a precocious, prolific bearer of tiny nuts that are a premier wildlife feed, especially favored by game birds. Compared to the chinkapin, the Chinese chestnut is a bigger tree producing bigger nuts, beginning production at an older age (3-7 yrs). Both of these species do not compete well in forests.
C. Landscape. Chinese chestnuts make attractive shade trees that don’t harbor lots of messy insects. However, the sharp spiny burs are nasty and a chore to remove from the lawn. Allegheny chinkapins are an interesting and attractive shrub that flowers in mid-summer and bears attractive clusters of nuts in the fall. The small, soft-spined burs of chinkapins are not as objectionable as those from Chinese chestnuts. For landscape trees, stick with seedlings, probably larger container stock.
D. Backyard nut production. To produce chestnuts for your own use and enjoyment the best choice is to plant a few Chinese chestnuts. You need to have at least two trees for cross-pollination, it’s better to have three or more. Ideally, they should be planted 25 to 40 ft apart, but if space is tight, you can put them as close as 15 ft if they have open space around them. Chestnuts need full sun for nut production. Seedling trees would do fine, especially if you plant twice as many as you want and then cut down the worst ones when they come into production.
E. Small-scale commercial production. If you would like to produce chestnuts and sell them for supplemental (not primary) income, this qualifies as “small-scale”. Because commercial chestnut production is just beginning and still facing many unknowns, you must be prepared to take risks and learn as you go. Consider the following strategy and planting plan. The best species is the Chinese; you might consider some hybrids. Because of the difficulty in finding and establishing grafted trees, you should start out with seedlings. Make sure that you get seedlings from good parents. Generally, it’s better to mix seedlings from different parents in the row, carefully labeling if you want to keep track of the mother. By mixing the families (the offspring from one mother or set of parents are called a “family”), you will spread out members of exceptionally good or bad families (don’t know at the outset which are the good or bad ones). Then, if you want to remove the bad trees, they will more likely be scattered throughout the planting. Likewise, the best ones will be scattered and you can thin around them. To allow removal of inferior trees, you should make the planting somewhat tight, say 20 ft by 40 ft. This spacing will allow you to keep all the trees that you want while at the same time allow you to remove up to half of the trees as they become crowded. Throughout the life of the planting good cultural practices should be employed including weed control, fertilizing, irrigation, and control of insects, deer, and rodents.
F. Large-scale commercial production. If you would like to produce chestnuts and sell them as a primary source of income, this qualifies as “large-scale”. This will probably require more than 50 acres of production. This should not be attempted until you or your neighbor has demonstrated small-scale commercial success. Many growers find that becoming a member of a chestnut growers’ cooperative is a way for several small-scale growers to combine their production and together become large scale.
Planting Chestnut Trees
Will chestnuts grow on my site?
Chestnuts require a well-drained soil, better drained than apple trees require. The most common mistake in chestnut cultivation is to plant them on sites that are too wet or too “heavy” (too much clay). Clay soils can be tolerated if there is good surface drainage (slope), but chestnuts do best on deep, sandy loams (rocks and gravel are okay). Soil pH should be acidic, between 4.5 and 6.5. Chestnuts won’t tolerate calcareous (limestone) soils. Chestnuts don’t require a very fertile soil, but do respond well to fertilizer.
Chestnut trees, like other fruit and nut trees, are sensitive to late spring frosts, and therefore, should be planted on hilltops, near large bodies of water, or other frost-protected sites. Chestnuts are very drought tolerant on good (deep soil) sites. However, in order to grow well, bear consistent crops, and bear large-sized nuts, they need adequate moisture throughout the growing season. Irrigation is not required in much of eastern North America, but it is necessary for consistent high yields of large sized chestnuts.
Chestnuts will grow over a broad climatic range from USDA plant hardiness zones 4 to 8, and seem to do best in areas that have hot summers. There is great genetic variation in climatic tolerance, esp. cold hardiness, so you need to choose trees adapted to your climate. Unfortunately, chestnuts have not yet been tested extensively enough in North America that we know which are the best trees for any particular area. So, you may just have to plant trees and let your climate choose the ones adapted to it. Our orchards have experienced -20 degrees F; all our trees tolerate this temperature.
What about planting distances, bearing age, and pollination?
Full size Chinese or Japanese chestnut trees require a spacing of 35 to 40 ft. European chestnuts require somewhat more space. To get higher early yields per acre, chestnuts may be planted tight. However, we’ve found that a spacing of 20 ft X 25 ft is too close (takes too much thinning before full production). We now think that planting at 20 ft X 40 ft allows for reasonably quick full production, followed by gradual removal of inferior trees beginning at age 15 to 20. For best nut production, there should be some space between adjacent tree crowns, i.e., when the branches of adjacent trees begin to overlap, it’s time to do some pruning or tree removal. When trees are young, it’s best to do little or no pruning – let the trees develop as many leaves as they can and grow as fast as they can. As trees get older and start to bear nuts, lower branches should be gradually removed to allow mowing and harvesting. Also, trees should be pruned down to one main stem. Chestnut seedlings should bear their first crop at 3 to 7 years of age. Trees that are vigorous and healthy bear sooner than stressed trees.
Chestnuts flower about 6 to 8 weeks after growth commences in the spring. They are mainly wind pollinated and require cross pollination to set nuts. Therefore, one tree by itself won’t have a crop. If you plant seedlings of pure species, pollination is seldom a problem. However, pollination can be a problem if the pollenizer is too far away (greater than 100 ft), or if there is a nutrient deficiency, esp. boron or phosphorus. If you plant grafted trees, you must interplant at least two cultivars that can pollinate each other. Many hybrids, including some hybrid cultivars, are pollen sterile. If you plant hybrids, it is probably a good idea to interplant some pure species to ensure adequate pollination.
Just contact us at empirechestnut@gmail.com if you have any questions about chestnut trees or about your order for chestnuts, chestnut trees or chestnut seed.
Pests & Diseases
Chestnut blight and Phytophthora root rot are the two major diseases of chestnut trees. In eastern North America, where chestnut blight occurs, it is best to plant blight resistant Chinese chestnuts. It’s important to realize, though, that Chinese chestnut trees vary considerably in blight resistance. Some individuals are quite susceptible while others are essentially immune to the disease. Phytophthora root rot is mainly a problem on wet soils. There is genetic variation in susceptibility to phytophthora, but the best control method is to plant trees on well drained sites. There aren’t any good fungicide treatments for either of these diseases.
There are many insects and mites which feed on chestnut leaves. Usually, the infestation levels are low enough that they don’t cause any economic damage, and control is not necessary. However, insects, such as caterpillars and Japanese beetles occasionally become serious enough that control is warranted. The chestnut gall wasp, which was introduced in the 1970’s has now spread over much the eastern USA. It’s a serious insect pest that affects shoot growth but has its own bio-controls that eventually render it a minor pest. Ambrosia beetles, which attack large stems (esp. graft unions), have caused serious problems in the South and Pacific Northwest. In eastern North America, the chestnut weevil is probably the most serious economic pest of chestnuts. The larvae feed on chestnut kernels resulting in “wormy nuts.” Chestnut weevils are fairly easy to control with prompt harvesting of the crop or with insecticides. In spite of these and other insect pests, many growers produce quality chestnuts without application of insecticides.
On good sites, chestnut trees will survive and grow with little or no care. However, from an economic standpoint, cultural inputs are justified in terms of increased yields, increased nut size, earlier yields, and consistent yields. Maintaining adequate soil fertility is probably the most important cultural input (fertilize them as if they were peach trees). Other important inputs are weed control around young trees, mowing the orchard twice or more per season, and mulching the trees. Irrigation is probably justified. Chestnut trees require much less pruning and training than other fruit trees. Pruning is done mainly after bearing begins and consists of removing lower branches to allow harvesting.
Harvesting
Under good conditions, a chestnut orchard will have its first worthwhile yield 4 to 5 years after planting. Under less than ideal conditions it may take a few years longer. Maximum production will begin after 10 to 20 years depending on spacing and genetic material. Seedling Chinese chestnut orchards in full production usually yield 1,000 to 2,000 lbs. per acre per year. Much higher yields have been reported from grafted orchards and from orchards with intensive inputs such as irrigation. High yields of 4,000 lbs. per acre or more may be possible. When forecasting yields, it’s always better to underestimate.
For the best quality and size, chestnuts should ripen on the tree until they fall, and then be picked up (harvested) promptly (the quicker the better). Nut drop usually occurs from mid-September through mid-October. They should not be shaken or knocked from the tree until the nut shells have turned brown. If they lie on the ground too long after they fall, they are subject to animal depredation, and they may dry excessively. Contrary to popular belief, freshly fallen chestnuts are not harmed by moisture (the Europeans routinely soak them under water for a week after harvest). At current prices, hand harvesting is affordable, but probably not the most economical. Mechanical harvesters exist, but thus far do not work well on the hilly, rainy sites where chestnuts do best. With the rapidly increasing acreage of chestnuts, though, better chestnut harvesters surely will be developed.