Pruning ornamental eucalypts (II): Eucalyptus gunnii example

Managing growth in ornamental eucalypts: Ongoing Eucalyptus gunnii sculpture in a temperate Atlantic garden

Gustavo Iglesias Trabado

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

We had previously seen in EUCALYPTOLOGICS some images on first year growth of ornamental Eucalyptus cultivated in our own garden and some explanatory texts on 5 steps of horticultural recommendations at each stage of cultivation in order to control their height and shape along their early growth years.

Fig. 1: Pollarded & pruned ornamental Eucalyptus 65 weeks after planting

The early results after performing sensible pollarding and pruning on garden Eucalyptus were quite pleasing (Fig. 1). We revisit now this topic to show the evolution of these pollarded and pruned eucalypts during their second autumn and winter on the ground.

Fig. 2: Pollarded & pruned ornamental Eucalyptus 75 weeks after planting (Click image to enlarge)

Retaining juvenile foliage in Eucalyptus is not an easy task. For the case of this garden specimen, leaf change started barely 15 months after planting (Fig. 2, left), so somewhere near age 36 months if we include the cultivation cycle of this plant at nursery prior to planting.

When eucalypt species bearing striking juvenile foliage as Eucalyptus gunnii and other similar looking types start showing intermediate leaves, the normal thought of a gardener involves pruning quickly to "remove the odd looking branches".

But this can be a hasty decision if done without considering the timeframes of your frost risk season. In our case, we decided to do some minor pruning (Fig. 2, right) and wait for the veredict of winter frosts before taking a too drastic step.

Fig 3: Example of frost event putting Eucalyptus cold hardiness to good test

Some 40 frost events later, including a steep air temperature drop from 12ºC (53ºF) to -8.5ºC (17ºF) in just 18 hours (Fig. 3), the overall status of this plant is good. Not surprising if we consider it is one of the cold hardiest Eucalyptus and it can be grown safely in the climatic conditions of my garden, unlike others. However, the newest and most fragile growth was lightly battered by frost and chilly winds and showed a mild degree of frost damage after the worst of winter (Fig. 4, left).

Fig. 4: Pollarded & pruned ornamental Eucalyptus 100 weeks after planting (Click image to enlarge)

So, in this case and regardless of our haste to prune in a high risk season as late autumn, Captain Winter itself showed us what was to be pruned on time once the highest risk of catastrophic frosts is over for this winter and the first signs of spring appear (Fig. 4, left). A simple pruning intervention took place on the leader branch, removing damaged foliage and some 0.5 meters of height growth (Fig. 4, right) by cutting some inches above a nice trunk area where several lateral branches grow in several directions. It is expected several of these lateral branches do gain in size at once, avoiding apical dominance of just one of them.

And now, spring has just arrived here. Some extra clipping operations are to be performed on the latest growth of these lateral branches to encourage a thicker foliage. And after that is done, a new growth season starts.

This pollarded and repeatedly pruned "big bonsai" Eucalyptus gunnii is being tamed to try to fit it in small garden designs via regular size control. If no operation was performed to regulate early growth during the first 100 weeks, current tree height would be in the range of 6 to 8 meters, basal branches bearing juvenile foliage would have already been lost and tree stability in high wind events might be compromised.

Also in this site

Pruning ornamental eucalypts: Sculpting Eucalyptus gunnii


Ornamental Eucalyptus: from seed to sculpted "Big Bonsai" container plants

Ornamental Eucalyptus as dieback perennials: taking advantage of plant resurrection


Grow Eucalyptus from seed: it is in the details


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GIT's Eucalyptology Topics

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© 2007-2008 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.