Articles
EFFECT OF TREATMENT WITH IBA ON ROOTING OF ORNAMENTAL CONIFERS
Boix, lecturer in this Department.
In our trials we have applied, various different methods of propagation: seed, cuttings (hardwood and semi-hardwood) layering and grafting, to the commonest ornamental conifers in Spain.
We have proved that the rooting of cuttings of different varieties of genera Picea, Abies, Pinus, Cedrus and Cupressus is almost impossible at commercial level, in Spanish ecological conditions; so that these genera grafting and propagation by seeds, seem to be the only current commercial methods of propagation.
Chamaecyparis, Juniperus, Taxus and Thuya are the genera which, in our trials, have responded best to the rooting of cuttings; it has also been possible to root good percentages of Criptomeria and Sequoiadendron.
In all cases we have been able to prove that it is essential to have stock plant available in sufficient quantity: otherwise the ornamental value of the isolated specimens can be damaged when the wood is cut; in addition we have also proved that success depends a lot on the time of year in which the cuttings are taken.
In our case, the best rootings were obtained in November, shortly after the beginning of rest.
Different species of each genera have given variable results, which can be seen in Table 1.
However, even within each species, the varieties sometimes react with greater variability than the species themselves.
For this reason, after several preliminary trials, we have considered of interest the study of the possibilities of rooting at variety level.