Pruning Eucalyptus: there are some risks to minimise

Prune Eucalyptus with care, they will be grateful

Or how to avoid unnecesary damage to pruned Eucalyptus

Gustavo Iglesias Trabado
GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal - www.git-forestry.com - EUCALYPTOLOGICS

If you decide to give pruning and/or clipping a go in order to keep your ornamental Eucalyptus plant size controlled to some extent it is important keeping in mind that, as with any other plant being, secateur wounds require some caution. A first caution is trying to avoid freezing events affecting recently pruned plants, which can cause bark detachments and further dieback "down the cut". But a second and maybe more important because of less predictable caution has to do with trying to avoid wound infection by decay fungi.

Some important risk factors for the later have to do with climatic conditions (high humidity, no winds, occasional rains being risky), with plant isolation from infection sources (proximity to other plants or plant based materials susceptible of hosting decay fungi), and of course of the number and intensity of wounds (potential entry points for pathogens).

Many fungi can cause decay on pruned trees, and many are common in fruit trees and other very common ornamental hardwoods in humid temperate gardens. Their spores are released in high humidity conditions and their colonisation of fresh cutting wounds can lead to undesired effects as Silver Leaf, causing dieback on whole shoots and hence an aesthetic nuisance or if a serious case, plant mortality.

Pruning Risk Minimisation for Eucalyptus

Some possible ways to try to minimise these two risks (frost damage and fungal decay) in ornamental eucalypts are:

• Delaying pruning operations until there is enough safety of harsh freezing events not happening on recently wounded plants
• Trying to delay pruning operations until dry days are more common (depends on the type of spring and rainfall patterns you have), choosing sunny and windy days if possible and better even if it has not rained or been foggy the previous night
• Trying to avoid having favourable environments for fungal growth near the pruned plants (wood debris, sawdust, organic material suitable for the compost bin)
• Monitoring your garden for fungal reproductive organs growing on wood and keeping an eye on them to schedule pruning after the mushrooms are scorched (their spores have been released)
• Applying the protective layer of a good quality pruning wound dressing immediately after cutting, especially in large wounds
• Keeping freshly pruned potted plants outside of the greenhouse until pruning wounds age if these are to be kept in high humidity and warm temperature (+15ºC) conditions and there are potential sources of fungal inoculum nearby
• If the worse happens, removing and destroying infected plant tissue if that is possible without causing new fresh wounds
• If the worse happens and you have more than one specimen plant, observing variation in damage to try to screen individuals with higher tolerance to pathogens

GIT's Eucalyptology Topics

Subscribe to receive EUCALYPTOLOGICS via RSS

Subscribe to receive EUCALYPTOLOGICS via e-mail

© 2007 Gustavo Iglesias Trabado. Please contact us if you want to use all or part of this text and photography elsewhere. We like to share, but we do not like rudeness.