ID-77 Nut Tree Growing in Kentucky Joseph G. Masabni, John G. Strang, R. Terry Jones, Horticulture; Ric Bessin, Entomology; John R. Hartman, Plant Pathology entucky is generally well suited for Table 1. Planting distance and estimated first deep. One or two years later, graft or growing nut trees. Northern pe- harvest of various nut trees. bud the largest of the three seedlings to K Planting First cans, black walnuts, heartnuts, hickory Distance Harvest the desired variety and remove the oth- nuts, hardy Persian walnuts (Carpath- Nut Type (feet) (years) er two. Exceptions: Chinese chestnuts ian strain), American hazelnuts, and Black Walnut 50 x 50 4-7 are not difficult to graft, but rootstock Chinese chestnuts all grow well in the Butternut 50 x 50 3-4 incompatibility may be a problem if state. Most nut trees are grown by hob- Persian Walnut 35 x 35 5-6 the cultivar being grafted is not placed Chinese Chestnut 40 x 50 4-5 byists and backyard gardeners. Several onto a seedling originating from this Hazelnut 15 x 15 4-5 varieties appear to have potential for Heartnut 35 x 35 3-4 cultivar. Hardy American or Eastern commercial production, particularly Hican 50 x 50 10-12 filberts are difficult to graft and in the some of the USDA pecan selections Hickory 50 x 50 10-12 past have been propagated by seed. and some Chinese chestnut varieties. Pecan 50 x 50 5-8 New blight-resistant varieties have been Nut trees grow best in deep, well- and will continue to be developed and drained soil of medium to good fertility available for purchase. If propagation is with a soil pH of 6.5 to 6.8. Chinese Planting Seed not feasible, grafted or budded nursery chestnuts grow best on acidic soils. Nut seeds are generally planted stock is recommended. Pecan growing in Kentucky should about 2 inches deep, soon after harvest be limited to northern varieties because in the fall. They do not germinate until Planting Trees Kentucky’s growing season is usually late spring. The “Tin Can” planting • Early spring planting of nursery nut not long enough for southern pecans to system helps reduce losses to mice, trees is better than fall planting be- mature, (i.e., for kernels to fill the shell). squirrels, and other wildlife that may cause it reduces the chance of winter Nuts of northern pecan varieties will eat them. Simply remove the top of a injury. not mature at higher elevations where tin can and, with a knife, make two • Plant trees as soon as possible after day and night summer temperatures cuts across the bottom, crossing in the delivery. vary greatly. However, trees do grow center. Push the empty can into the soil • Do not let roots dry out. Tree surviv- well on these sites and make excellent over the planted nut until the cut end al may often be improved by soaking shade trees. is flush with the soil surface. In early the tree roots in water for 24 hours If nuts of a particular variety are spring slightly turn up the metal tips at before planting. planted they will not produce a tree of the center of the can so that the seed- • Prune off broken roots and shorten that variety. Rather, to get a tree of a ling can grow through the opening but long ones before planting. certain variety, wood from that variety pests still cannot get it. As the seedling • Dig a deep hole, wide enough so that must be grafted onto a rootstock. grows, turn the tips back farther. lateral roots can spread out in their All nut trees except filberts become There is no need to remove the tin natural positions and deep enough quite large. Because nut trees take can because it usually rusts out, par- so the tap root (if there is one) will many years to fill their allotted space, ticularly if it has been burned to remove not bend. some growers plant filler trees and the galvanized coating. However, an • Leave the tap root as long as possi- remove them later, before branches of aluminum can does not rust and must ble. Trees should be planted as deep adjoining trees meet. Table 1 shows be cut down one side to permit easy as they were in the nursery. Examine suggested minimum permanent spac- removal before it girdles the young tree. tree trunks to find the soil line mark. ing and average years to first harvest If you wish to directly plant seeds • Set the tree in the hole and fill with when grafted trees are set out. instead of transplanting, then plant soil. If the soil is not too wet, firm three nuts where the tree is to mature. the soil around the roots with the Position them in a triangular pattern hands. spaced about 1 foot apart and 2 inches • Water trees well after planting to Large dead areas on the trunk usually settle the soil around the roots, and Pruning result from this type of injury. then weekly throughout the summer Remove about one-third of the top Sunscald may be prevented by paint- during dry conditions. Watering growth at planting. Cut the terminal ing the lower 30 to 36 inches of trunk trees during the first season is ex- shoot just above a bud and remove and the bases of some scaffold limbs tremely important in establishment. all side branches close to the trunk. with an interior white latex paint in • Backfill around all planted trees This encourages survival and strong the fall, by using a white plastic rodent with loose soil after rains have set- regrowth. Prune young trees lightly guard, or by wrapping the trunk with tled the soil in the planting holes. during the first few years in February aluminum foil. These actions prevent or March to select scaffold limbs with the southwest side of the tree trunk Fertilizing wide crotch angles and to maintain from heating up and help eliminate a central leader. Branches should be sunscald injury. Take a soil test and, based on its pruned off the trunk to a height of at If a white plastic rodent guard is not results, adjust soil fertility at least a least 6 feet if you plan to use a metal used around the trunk following plant- month before planting. Adjust the pH tree guard to control squirrels. When ing, place a loose cylinder of ¼-inch to 6.5 and bring phosphorus and potas- 10 to 15 good scaffold limbs that are hardware cloth at least 18 inches high sium levels into the high soil test range. well spaced on the trunk have been around the trunk. This will keep rabbits Do not fertilize at planting because developed, cut the central leader back from damaging or killing young trees. doing so can injure roots. to a lateral limb, and train the tree to Remove mulch from the base of the After the first year, follow this proce- a modified central leader shape. For trees in the fall to prevent vole damage. dure for fertilization: (1) Determine the more detailed explanations of pruning, trunk diameter 5 inches above ground. see Cooperative Extension publication, (2) For each inch of trunk diameter, Growing Fruit at Home in Kentucky Irrigation, Mulching, apply 1 lb of 10-10-10 fertilizer per (HO-64). Only limited pruning is and Weed Control tree, but no more than 1⁄3 lb of actual needed on bearing trees. Remove dead Inadequate weed control and lack of nitrogen per inch of trunk diameter limbs to a side limb or to the trunk to water are the two primary reasons for per season. (3) Place fertilizer under the promote rapid healing and avoid trunk poor nut tree growth, even death, par- tree periphery in late February. (4) Take decay. When trees are 20 to 30 years ticularly in the first season of growth. soil tests annually and apply lime as old, thin out some of the top scaffold Even mowed grass competes heavily needed to prevent soil pH from falling limbs to allow light into the interior of with young trees for nutrients and below 6.0. the trees. water. Maintain a vegetation-free area Trace elements are very important American hazelnuts are grown as a beneath the trees to reduce competi- in nut production. Zinc is the most bush and pruning consists of thinning tion from weeds. This area should be critical trace element. When zinc out smaller, weaker shoots by remov- 4 to 6 feet in diameter and expanded is lacking or present in insufficient ing them at ground level. Also, remove as the trees get older. Mulching with quantities, nutlets fail to set and yields some of the center shoots to open up wood chips, bark, hay, or straw is very are very low. Zinc is best applied as a the center of the bush, admit light, beneficial. Lay at least 4 inches of mulch foliar spray just after pollination at a and prevent bearing only on the bush for best results. Mulch should be kept rate of 1 to 2 lb of zinc sulfate/100 gal periphery. A plant should have five to at least 6 inches away from the tree base of water (1 to 2 tbsp/gal) for young trees seven main shoots. Grafted hazelnuts to avoid injury from mulch heating and and 5 to 10 lb/100 gal for mature trees. are grown as a tree and all suckers need to help reduce rodent damage. Apply two more times at two- to three- to be removed from the base.