Planting Black Walnut

Black walnut (Juglans nigra) is may be found in draws and along ated with cultivation and the use of the most commercially valuable tree the base of north- and east-facing heavy equipment — can hinder root in Kansas. Its chocolate-colored slopes of less than 15 percent. Black development. wood is highly desired for fine walnut grows best when crowns are The most important nutrients furniture, veneer, interior finish, exposed to full sun in an environ- for good black walnut growth are cabinets, and gun stocks. The wood ment protected from wind and available at a pH between 5 and 8, is straight grained, strong, heavy, extreme temperature variations. however, a range between 6.5 and decay resistant, easily worked with Soils. Optimum growth occurs in 7.2 is best. Most Kansas soils suit- tools, and shrinks and swells little loamy soils (both sand and silt) of able for black walnut have adequate after seasoning. Many consider the medium texture that is at least 3 feet fertility. However, it is always a nutmeats a delicacy and the ground deep. Avoid soils with restrictive good idea to test soil before planting shells are used as abrasives. layers of coarse sand, gravel, rock, since soil amendments are most Planting black walnut is a good or heavy clay. Black walnut likes practical during site preparation. For long-term investment for land- fertile, moist, but well-drained, soils a small fee, local K-State Research owners. In most cases, the cost of with high organic matter. Alternate and Extension offices can provide planting is borne by one generation streaks or blotches of yellowish soil tests. and the income from sales received brown, red, or gray may be an indi- It is not a good idea to fertilize by the next. However, financial cator of poor internal drainage. black walnut the first year of incentives are often available Naturally occurring fragipans planting unless the fertilizer is a through government programs to — layers of compacted soil associ- slow-release formulation or thoughly help landowners with establishment costs. This publication outlines the elements necessary for successful Black Walnut Soil Nutrient establishment of black walnut. Requirements for Major Elements

Site Selection pH 6.5 to 7.2 Black walnut will grow under a variety of site conditions. However, Organic Matter 2 to 3.5% selecting a site where black walnut will thrive is an important factor Nitrogen 0.25 to 0.3% for success. Most often the best sites will be found on well-drained Phosphate 60 to 80 pounds per acre loamy bottomlands not subject to prolonged flooding (3 to 4 days of Calcium 3,000 to 4,000 pounds per acre standing water). During the growing Potassium 225 to 275 pounds per acre season, floods that submerge young crowns for more than 2 days Magnesium 375 to 600 pounds per acre usually kill the trees. Good sites

Kansas Forest Service 1 mixed into the soil during site prepa- case basis since in some situations make fall treatments more effective. ration. Without a good weed-control soil may become compacted into Cool-season grasses also may be program, any fertilization will be a “plow pan” or “hard pan” from treated in early summer if the grass wasted. Fertilizing pole-sized trees years of repeated cultivation and use is actively growing in the boot-to- is more likely to provide a better of heavy equipment on the site. In early seedhead stage. Kill grass that economic return. those cases plow or deep chisel in surrounds tree plantations and apply County soil information is avail- the fall and disc before planting in annual spot treatments as necessary able on the Web site, http://soil- the spring. However, even with such to prevent grass spreading back into datamart.nrcs.usda.gov and from treatments there is a possibility that the trees. After herbicide treatment, local conservation districts, Natural the plow pan will return. Apply a cultivate the site according to the Resources Conservation Service, glyphosate herbicide in the spring instructions provided for abandoned and local K-State Research and before planting if weeds and grass cropland. Extension offices. The informa- are present. Forest Openings and tion may include soil type maps Abandoned Cropland. (invaded Conversion. Black walnut requires (Verdigris and Kennebec are some by grass, woody brush, or perennial full overhead sunlight for proper of the best soils for black walnut), weeds) If undesirable woody vegeta- growth and development. For this soil descriptions, and the suitability tion is present, treat with a nonselec- reason it is best to clear a circular of various soils for tree planting. tive herbicide after green-up in the area of at least 1 acre or 236 feet Keep in mind that although a soil spring, 1 year before planting, by in diameter. Two acres are even type may be listed as suitable for broadcast spraying. Selective herbi- better (333 feet in diameter circle). black walnut, individual fields can cide treatment also may be required. If deer damage is a problem, then vary considerably. The following fall, mow as close to even larger areas should be cleared Before selecting a site for a black the ground as possible, and plow to and damage protection measures walnut plantation, it is always a good a 12- to 18-inch depth. Disk prior to considered. idea to examine soil characteristics spring planting. When creating new openings or firsthand with a probe or by digging Grassland and Pasture Sites. expanding existing ones, all trees a hole. Apply a broadcast treatment with a that shade the planting area should glyphosate product to kill grasses. be killed with a selective herbicide. Site Preparation Timing of application depends Converting areas of unwanted trees Good site preparation saves a on whether it is a warm-season such as honeylocust, boxelder, elm, landowner time and money, and (native) or cool-season grass such and osage orange may be done requires less weed and grass control as brome or fescue. Warm-season by hand clearing or bulldozing. after planting. Site preparation grass should be killed in August in Treat stumps and girdle cuts with involves removing competitive vege- the boot-to-early seedhead stage an approved herbicide to prevent tation, usually through cultivation and cool-season grass in the fall sprouting. If competing grasses or herbicide treatment. Site prepara- when there is 6 to 12 inches of new and/or shrubs exist, treat as outlined tion also can require improving the growth. Burning or mowing in in abandoned cropland. Plant black physical and chemical condition of the spring can reduce residue and walnuts into existing forest litter. the soil. Methods and the degree of site preparation depend on the existing groundcover and erosion Figure 1. A walnut stratifying pit. potential. General recommendations for preparing various planting sites are listed. Seek professional advice ����������������� from a forester for specific recom- ���� ������������������ mendations. Cropland. Since cropland is culti- ����� ������������������� vated, it may not require site prepa- ������������� ration, which in turn conserves soil moisture and limits the introduction of weed and grass seed. Whether ������������������ or not to cultivate a cropland site ��������������� ���� should be decided on a case-by- 2 Underplantings. Planting black Trees should be planted at square hulls can be removed. If hulls are walnuts in the shade of existing spacings to encourage canopy removed, floating nuts in a tub of trees is recommended only if all closure and for distribution purposes water can test viability. Discard all competing trees are removed from when the thinning process begins. nuts that float and store in a strati- the site within 2 years. Dense shrub When planting black walnut for fying pit (Figure 1) or in a refriger- growth, small trees, and stump nut production, recommended tree ator at 41 degrees Fahrenheit. It may sprouts must be controlled. spacing is 30 feet by 30 feet, or 48 be necessary to cover stratifying pits seedlings per acre. Although any with chicken wire to protect nuts Selecting Seedlings and Nuts walnut tree can be used as rootstock from predators. Either seedlings or nuts may be for grafting on quality nut producing Establishing black walnut by seed planted. Bare-root black walnut cultivars, nuts from the cultivars is a good choice for large plant- seedlings and stratified nuts can Kwik-Krop, Sparrow, and Giles ings and for people who want to be ordered for spring planting produce superior rootstock trees. plant in the fall. Nut plantings avoid from Kansas Forest Service, transplant shock that can occur in through local K-State Research and Planting Nuts seedlings. Knowledge of correct Extension offices, or county conser- Black walnut is a good tree to collection, handling, planting, and vation district offices. plant from seed. It tends to have a weed and grass control for the first 3 Know the source of the seedlings 60 to 70 percent germination rate years is critical for success. Assume and nuts. Research on provenance and although the husk is messy, it that purchased seed is neither strati- performance suggests that seeds prevents the seed from drying out. fied nor tested, and must be planted collected from trees within 100 Large nut crops occur every two to in the fall or stratified by cold miles north or south of the planting three years. Nuts can be collected storage for spring planting. site have the greatest survival rate. locally beginning in late August Seeds collected from areas within when husks change color. Seed Planting Seedlings 200 miles south of the planting site viability percentage can be esti- Seedlings can be planted with grow significantly taller. It is also a mated before collecting a lot of nuts a tree planting bar, shovel, power good idea to limit the seed source from a tree by cracking or cutting 10 auger, or tree planting machine. to within 200 miles east and west of seeds to determine freshness, color, Planting holes should be wide and the planting site. Seed sources east moisture and the presence of mold deep enough to accommodate roots of Missouri should not be considered or insects. Collect seed from high without doubling or twisting. for Kansas. Seedlings from other quality trees and store it in piles Black walnut seedlings often have parts of the country are generally not less than 10 inches deep to avoid a long, well-developed taproot and adapted to the Kansas climate and “heating up” and losing viability. a large mass of fine feeder roots. growing conditions. Nut piles should be protected from If possible avoid pruning roots. squirrels. However, roots grow so quickly in Spacing Nuts should be planted in the fall nurseries that it may be necessary Proper spacing depends on with the husk on at a 2- to 3-inch to lightly prune them with sharp whether trees are being grown for depth. Recommended rates for pruning shears to fit seedlings into nut production or for timber prod- broadcasting black walnut, which planting holes. Plant seedlings at or ucts. For timber production, no may be accomplished with a fertil- ½ inch below the depth they grew fewer than 300 trees per acre (12 izer spreader, are 3,000 to 4,800 in the nursery, evident by a color feet by 12 feet) should be planted. A seeds per acre. Recommended rates change just above the swollen area 10-foot by 10-foot spacing provides for planting seed in rows with a on the taproot. Water trees imme- 436 trees per acre. Spacings less direct seeding machine or by hand diately after planting and, if prac- than 10 feet by 10 feet will provide are 1,500 to 3,000 seeds per acre. tical, every 7 to 10 days during a even more trees to choose from Stratified nuts can be planted in prolonged drought. when selecting crop trees, which the spring. Walnuts are stratified by Species such as red oak and other will increase growth and stem being subjected to 90 to 120 days of trees with similar growth rates can quality, shortening the time it takes 31 to 41 degrees Fahrenheit temper- be planted along with black walnut for canopy closure and reducing the atures (what they would normally in the plantation. Shrubs planted time span required for weed and endure if planted in the fall). Nuts along borders of the plantation will grass control. may be stratified with hulls on, or provide food, cover, and nesting

3 habitat for wildlife. Two experi- not subject to flooding, fabric mulch Additional Information enced tree planters can hand plant can be used to control vegetation in Tree planting plans, site evalu- 1,000 to 1,500 trees in a day. For the row. Some introduced ground ation, and post-planting advice large plantations, a three-person covers — such as hairy and crown are available from your district machine planting crew can plant vetch, or Crimson clover — can forester, local K-State Research and 4,000 to 6,000 seedlings in a actually increase tree growth if Extension office, Natural Resources day. Tree planting machines are managed properly. Conservation Services county available from the Kansas Forest Tree plantings must be protected office, and Kansas Forest Service at Service. In addition, several county from fire, livestock, wildlife Kansas State University, Manhattan. conservation districts and district damage, and misuse of herbicides. Programs may be available to offices of the Kansas Department Inspect your planting periodi- help with the cost of planting and of Wildlife and Parks have tree- cally for problems such as insects, establishing black walnut stands. planting machines available for disease, and wind or ice damage. public use. Deer damage has become a Related Publications common problem and should be The following publications are Post-Planting Care considered before planting. available on the World Wide Web at The area around young trees www.oznet.ksu.edu should be weeded as often as neces- • Tree Planting Guide, L-596 sary to prevent competition, espe- • Chemical Weed Control in Tree cially during the first 3 to 5 years. and Shrub Plantings, MF-656 To obtain best growth, keep trees • Improving Black Walnut Stands, free of weed and grass. Weeds can L-718 be controlled over the entire plan- • Deer Damage Control Options, tation area, in 4-foot strips along C-728 The following publication is avail- tree rows, or in a 4- to 6-foot radius able at on the World Wide Web at around each tree. Both cultivation www.centerforagroforestry.org/ and the use of approved pre- and/or • Propagating Pecan and Black postemergence herbicides are effec- Walnut in Missouri, University of tive weed control options. In areas Missouri Center for Agroforestry This publication is made available in cooperation with the USDA Forest Service.

Robert L. Atchison Kansas Forest Service 2610 Claflin Road Manhattan, Kansas 66502-2798 (785) 532-3300 www.kansasforests.org

Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. Publications from Kansas State University are available on the World Wide Web at: www.oznet.ksu.edu Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, credit Robert L. Atchison, Planting Black Walnut, Kansas State University, June 2005.

Kansas State University Agricultural Experiment Station and Cooperative Extension Service L-731 June 2005 K-State Research and Extension is an equal opportunity provider and employer. Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, as amended. Kansas State University, County Extension Councils, Extension Districts, and United States Department of Agriculture Cooperating, Fred A. Cholick, Director. 4