Many species of Juglans and their hybrids are very difficult to propagate by conventional hardwood or semi-hardwood cuttings. We have been most successful by taking cuttings from hedged mother trees, treating the cuttings with high concentrations of K-IBA (8000 mg/L or more) and sticking them in a solid rooting medium (Horti Cubes®, for example) and placing them on a bottom -heated bed at about 26° C outdoors in winter (hardwood cuttings) or under mist in a greenhouse (semi-hardwood cuttings) in mid-summer.
The related species, Chinese wingnut, is very easy to root from hardwood and semi-hardwood cuttings using methods as described above, and for this species, use of hedged material is not necessary.
We have recently initiated semi-hardwood cutting propagation of a set of seedlings of wingnut accession DJUG 1.09 to facilitate clonally replicated re-testing of individual progeny that appear to segregate 1:1 for crown gall resistance.
Fig. 1-3. Semi-hardwood wingnut cuttings.