Hybrid Hickory Variety Recommendations and Propagation Trials

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2024: $15,000.00
Projected End Date: 02/15/2026
Grant Recipient: Dispersion Farms
Region: North Central
State: Wisconsin
Project Coordinator:
Alex Tanke
Dispersion Farms


  • Nuts: Hickories


  • Crop Production: agroforestry

    Proposal summary:

    This is a research project with two main barriers, both of which
    will be important to break in order to make hickories a crop in
    the upper midwest.

    1. Tree evaluations need to be done on hundreds of hybrid
      individuals in the upper midwest to provide variety
      recommendations for growers in the upper Midwest. Currently, only
      a small handful of subpar hickory selections have been made and
      often have been trialed only outside of zone 4/5 upper midwest.
      Additionally, evaluations are almost entirely anecdotal and
      insufficient to give growers security in planting varieties that
      are of high cost and may take over a decade to bear nuts.
    2. A procedure for epicotyl grafting hickories (grafting onto a
      sprouted nut) in zone 4/5 needs to be developed. Traditional
      nursery growing of hickories is challenging and problematic due
      to the high costs of producing grafted trees because of slow
      seedling shoot growth, strong taproot dominance, and the stress
      responses of hickories.

    Project objectives from proposal:

    The first objective is to select 10 hybrid hickory varieties to
    be recommended to growers in zone 4/5 upper midwest that will
    provide maximum profitability and flexibility to the grower and
    release them for sale. I will select hickory trees that are easy
    to propagate, fast growing, disease resistant, heavy bearing,
    easy to harvest and husk, and bears multipurpose nuts. A
    multipurpose nut that grows in zone 4/5 upper midwest can only be
    found in some bitternut shagbark hybrids. A multipurpose nut is
    one that can be used for multiple of the following purposes:
    home-scale cracking, machine cracking, oil pressing, and milking.
    The characteristics that allow for a combination of these four
    puroses are:

    • the kernel weight should be as large as possible with 2.0g as
      a minimum
    • the nut should have a thin enough shell that it can be
      pressed in-shell for oil reliably. Current knowledge estimates
      that the nut should be at or exceed 47% kernel.
    • the nut should crack out exceedingly well in a home scale
      hand cracker with at least 50% of kernel to halves and 90% easy
      extraction to large pieces
    • the nut should be milkable which requires that the kernel,
      pellicle, and shell not to contain tannins.
    • The nut shape should lend itself to automated machine

    The second objective of this project is to determine the details
    in the procedure of epicotyl grafting hickories to get maximal
    grafting success. Though I have successfully epicotyl grafted
    with Black Walnut and the method has been successful with pecan,
    epicotyl grafting has not been applied to bitternuts, shagbarks,
    or their hybrids. Many specifics of the epicotyl grafting process
    with hickories needs to be discovered including: the best hybrid
    rootstock, the best shoot development stage for high graft
    success and rapid growth, the best waxing and compression method,
    and the lowest input nursery growing conditions that work with
    the Wisconsin climate.

    For the epicotyl grafting trials, three rootstocks will be
    tested: "Fairbanks", "Weschcke", and a 3.0g kernel shagbark. Past
    trials show that pure shagbark and "Weschcke" produce the
    thickest diameter epicotyl which is easier to handle. 100%
    beeswax will be used that has no oil in the mix because the oil
    seems to have killed callus in past trials. Suxgumoe Plants Graft Clips will be used as
    determined by my past trials and sizing.
    Three compression
    and wrapping methods will be used: parafilm wrapping, parafilm
    wrapping and clipping, and only clipping. All grafts will be
    waxed to the bottom of the graft union. Nuts will be placed in a
    germ chamber for 20 to 25 days at 90F and epicotyls of length
    varying from 1 inch to 6 inches will be grafted, segregated, and
    labeled with all characteristics of relevance to this study.
    Grafts will be callused in a greenhouse heated to 70F, fans will
    run above 85F, and sides will be rolled up to help keep temps
    within this range. After 5 weeks, 75% of grafts will be planted
    into a rodent proof nursery bed for two years and 25% will be
    planted into 9" tall 4" wide tree pots. Winter survival rates
    will be noted for field planted grafts. Nut germination will be
    initiated on ~March 25th, grafting will occur on ~April 20th, and
    transplanting will occur on ~May 25th. A minimum of 300 grafts
    will be made.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.