The flush development of evergreen recurrent flushing perennials: an experimental overview with insights into the flowering of olive

Abstract

Recurrent flushing perennials are those that grow by episodic waves of shoot extension under conditions continuously favourable for growth. Here we review the habit for evergreen perennials. The commencement of a new flush appears to depend on the stimulation of buds by plant growth regulators. The determination of a new flush as vegetative or floral most likely occurs during early shoot development. Cool temperatures are usually florally inductive, but other factors such as periods of water stress before flush commencement, and low crop loads may also enhance induction. There is little evidence for the control of the final size of vegetative shoots, and even less for the size of floral shoots. The time between successive flushes is cyclic and temperature dependent. New work with olive is presented and shows that pruning increases the proportions of vegetative shoots to develop from comparable nodes of pruned and non-pruned branches. It also shows that immature vegetative flushes on olive branches in winter inhibit flowering to some extent, a result previously shown for other evergreen recurrent flushing trees.