2016 January Meeting - Eucalyptus Demonstration

2016 started at the Bonsai Society of Victoria with a very entertaining and interesting demonstration by Kevin about Eucalypts and the art of bonsai.  Eucalypts, an Australian native plant, are part of the Myrtaceae family with hundreds of different species having a wide variation in shape and style.  This also means there are lots of differences in how to grow them as bonsai.  Kevin has been exploring the issues facing bonsai artists working with eucalypts and some of his learnings are included below.

Yellow Box(Small) & Red Box(Large)
While there are enormous variations in trunks, bark and leaves, the general habit with branches is to stretch up rather than spread creating many challenges for the bonsai artists.  See examples in display photos below.
Most eucalypt species can be successfully grown in a Melbourne backyard with a judicious choice of location.
It can prove very difficult to develop eucalypts with mature leaves in a bonsai.  Kevin has a 35 year old Red Box that still sends out juvenile leaves.
Kevin discussing his Red Box(Large)
Wiring eucalypts is possible but you need to watch closely and not leave it on too long.  This activity can also encourage a new burst of growth.
Eucalypts naturally live in environments subject to bushfires and have found ways to survive.  Bonsai artists can use this capability to assist in the development process.  Kevin has found that burning the leaves is often a good option when a tree is doing nothing.  A light scorch with burning newspaper can generate vigorous new growth opening up new development options.  This can be an option in the November to March period but please don't do it on a Total Fire Ban day.
Kevin encouraging a River Red Gum to regenerate.
Trees can be trimmed by pinching but if larger branches are cut, Kevin seals the cut immediately.
Lots of pests love eucalypts so keep a close watch.  See Eucalyptus Gall Wasp nodules on this River Red Gum.
Nodules from Eucalyptus Gall Wasp on River Red Gum
While generally eucalypts are hardy, the first transplant is often a high risk activity.  These starter plants tend to have long roots which you want to reduce and encourage more lateral roots.  Be very cautious.  Subsequent transplants are generally less risky.  Kevin uses an open potting mix, slow release fertiliser and half strength liquid fertiliser.  He is also exploring techniques( from Neil P.) used on deciduous trees to help develop surface roots.  See photos.

Black disk to encourage surface roots in a River Red Gum
If you want to try developing bonsai, look at River Red Gum, Red Box, Black Box, Red Ironbark, Mallee's, Snow Gum( slow grower), White Peppermint and Brittle Gum.
Species to avoid include Swamp Gum, Narrow Leaf Peppermint and Mountain Ash.
Samples used by Kevin in the demonstration.
Red Box(Large) & Yellow Box(Small)

Yellow Box - Eucalyptus melliodora

Red Box trunk close up

Red Ironbark - Eucalyptus sideroxylon with regrowth after crown burning in Dec.
Other trees on display.
Yellow Box - Eucalyptus melliodora

Fuchsia Group

River Red Gum - Eucalyptus camaldulensis

River Red Gum - Eucalyptus camaldulensis

Coastal Tea Tree Group - Leptospermum laevigatum

Brittle Gum - Eucalyptus mannifera

Yellow Box - Eucalyptus melliodora

Lemon Scented Gum - Corymbia citriodora