Ancymidol applications retard plant growth of woody ornamentals

Abstract

English; Trials with the growth retardant Ancymidol (the proposedgeneric name for alpha -cyclopropyl- alpha -(4-methoxyphenyl)-5-pyrimidinemethanol),generally as an emulsified concentrate, were made on 49 species andcultivars, over a range of dosages and with different methods ofapplication. The main effect was uniform dwarfing, although Pinuscanariensis, Juniperus chinensis 'San Jose', and J. horizontalis'Prostrata' failed to respond at all. The period of effectivenessvaried with species and dosage from 1-2 weeks for Pyracantha plantsto over 3 months for Eucalyptus viminalis, after which normal growthwas resumed; in Rhamnus alaternus, terminal growth ceased completelyduring this period. With E. viminalis, application of the preparationto the soil appeared to have more marked and persistent effects thandid foliar application; Ancymidol affected leaf breadth more thanleaf length, making the leaves smaller and narrower than normal.Other effects of Ancymidol were: reduction in the number of nodes;delay in flowering; and coarse, stunted and enlarged roots (aftersoil drenches at high concentrations) in some species.