Factors affecting the vegetative propagation of ash (Fraxinus excelsior L.) from semi-hardwood and hardwood cuttings

• Published in: New forests Vol. 56; no. 4; p. 42
• Main Authors: Negri, Isabel S., Gómez Barreiro, Pablo, Cockel, Christopher, Chapman, Ted
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2025; Springer Nature B.V
• Subjects: Age; Biomedical and Life Sciences; Butyric acid; Cuttings; Dieback; Forestry; Forests; Fraxinus excelsior; Hardwoods; Indole-3-butyric acid; Inoculation; Life Sciences; Peat; Plant propagation; Propagation; Rooting; Seeds; Trees; European ash; Tree maturity; Peat-free; Rooting hormones; Cuttings; Mycorrhiza
• ISSN: 0169-4286; 1573-5095
• DOI: 10.1007/s11056-025-10103-y

The threat of ash dieback ( Hymenoscyphus fraxineus ), which is decimating European ash ( Fraxinus excelsior ) populations, has heightened the need for a cheap and simple method to propagate potentially tolerant trees. We tested the effects of mother plant age, mycorrhiza, rooting hormone, timing and substrate type on the rooting of ash cuttings in order to optimise current propagation techniques. Semi-hardwood and hardwood cuttings from two age classes of mother plant were subject to factorially combined treatments. These included different substrate types (peat-based and peat-free), rooting hormone concentrations (0–2% indole-3-butyric acid), and mycorrhizal inoculations. The most effective treatment was tested on cuttings from an intermediate age class of potentially ash dieback-tolerant trees. None of the cuttings from trees of an intermediate or older age rooted. Cuttings taken from 1–3-year-old plants rooted readily, especially when taken as semi-hardwood cuttings (91% rooted, whereas 54% of hardwood cuttings rooted). The use of higher rooting hormone concentrations improved rooting percentages in all cuttings from young plants by about 10%. There were no differences in rooting between peat-based and peat-free substrates. Finally, mycorrhizal inoculations had no effect on semi-hardwood cuttings, but inhibited the rooting of hardwood cuttings. A good protocol was obtained using semi-hardwood cuttings of young material, which could be used to propagate juvenile or rejuvenated disease-tolerant ash.