Twenty years ago I became aware of and fascinated by a small to medium sized compact Australian tree which in late summer put on an incredible cover of vibrant red, scarlet or orange flowers. It was of course the Western Australian Flowering Gum, Corymbia ficifolia (previously Eucalyptus ficifolia).

I grew a few from seed from a well known tree in Ballarat which bore bright orange flowers. I planted out four of them. One produced similarly coloured flowers, one pale orange/salmon flowers, one red flowers and one white flowers. I had just proven how variable for flower colour this species can be when grown from seed. Every summer I looked around wherever I went for specimens of this amazing tree, and whenever possible took a close look at their flowers. In late February 1988, in Ballarat, I spotted another one which I had not seen before. It was a brilliant colour. But I will never forget my excitement as I approached the tree and saw how large the individual flowers were. I immediately recognised that this was a unique tree. There and then I resolved to preserve it. I knew that it could only be multiplied by vegetative propagation.

It has been a long story of research, experiments, trials and persistence to develop the techniques which I now use to propagate these trees. Some eucalypts can be propagated from cuttings. Some timber species, such as Eucalyptus nitens are propagated in large numbers in this way overseas. But C. ficifolia does not grow from cuttings, and despite much research with cuttings and with tissue culture, no practical or commercial method has turned up yet. However, many eucalypts can be grafted. Large numbers of timber species were grafted in years gone by to establish seed orchards. C. ficifolia has been grafted dating back to the last century. Ten and twenty years ago Victorians Neil Marriott, Doug McKenzie and others grafted a few. King's Park in Perth did a few in the 1960s and occasionally a few since. Austraflora Nursery in Melbourne tried a few at one stage. Most achieved only a poor success rate, and this seems to have been a factor in the low numbers produced.

Another factor that haunts all native plant grafting is scion to rootstock compatibility. Incompatibility failures do occur, however with C. ficifolia I can only find a few vague anecdotal reports. C. ficifolia is grafted mainly onto C. ficifolia, calophylla and maculata rootstock's. Will each of these combinations not only grow vigorously but also not break at the graft at some time in the future? I have planted out some long term trials, I will report the results in 25 years time! In recent years in Victoria, production of grafted trees has increased. They are regularly available in Melbourne and sell for about $30 each in 200mm pots. At times various nominated colours were sold, such as 'orange' and 'red'. More recently two named selections, 'Apollo' and 'Wildfire', have been available. My cultivar is named 'Vermilion Blaze' and is registered with the Australian Cultivar Registration Authority. It has larger than normal flowers and is a brilliant vermilion colour (between orange and scarlet). Some S.G.A.P. members have seen it. I have a number of trees already established in a range of locations as trials and as stockplants. I have committed myself to continue to work on the widespread establishment of this cultivar to the point where it is safe from extinction. I anticipate that limited numbers will be available for sale in a couple of years time.

Grafting delivers true to colour flowers, but there is a bonus, grafted C. ficifolia trees commence flowering at a much younger age than seedlings do, usually in the first or second season after planting out. However the species does not necessarily flower every year.

Eucalyptus ptychocarpa has been grafted in Queensland because its seedlings vary in flower colour. Some grafted hybrids of E. ptychocarpa and C. ficifolia, which suit the climate in northern Australia, have been released for sale recently. I have grafted a scion from a red flowered Eucalyptus leucoxylon tree onto a seedling rootstock of that species to avoid the one in five possibility of a seedling being white flowered. Eucalyptus scoparia has very variable foliage when grown from seed. Grafting could be used to produce the best form, which has dark narrow leaves and a weeping habit.

Another species, which I have grafted successfully, is Eucalyptus sideroxylon. There are some magnificent forms of this species with beautiful glaucous leaves and pink flowers. I think a selection should be made and then promoted. It would do wonders for the public image of native trees and might gain a foothold amongst the exotics as a street and landscape tree.

GRAFTING CORYMBIA FICIFOLIA

I use seed from any C. ficifolia tree. Sowing time is mid October. The potting mix I use is two parts of 3/16" (4.5mm) crushed quartz (with smaller and larger particles sieved out) and one part (moistened and expanded) coir fibre (palm peat). (Other mixes can be used). Add 1 gram/litre iron sulphate and 1 gram/litre Osmocote Plus (retail tubs with 4.4% phosphorus). Low phosphorus fertilisers are unsuitable. The pots I use are Plastamatic T7. They are 80mm diameter by 150mm high and have very little taper. Any smaller pot or tube is unsuitable. Sow one seed per pot. A range of sunny situations is suitable, however adequate air circulation or direct exposure to the open air is essential to avoid damping off. Once seeds have germinated individual pots may need to be rotated as often as daily to maintain straight growth of the seedlings. Move pots outside within 2 to 3 weeks. Overhead cover is needed on any night when a frost is possible. I fertilise each pot individually at the rate of 1 gram/litre on a monthly basis. Nip back all laterals up to a height of 50mm and remove all laterals between 50mm and 180mm. By mid January the pots must be spaced out by making pot width spaces between every second row.

Grafting is in mid February. Shoots, preferably with some second year wood attached, are cut from the stock tree. This material is sprayed with water and immediately placed in plastic bags. These are transported in an 'Esky' cooler if the weather is hot.

A seedling rootstock is cut off at a height of between 125mm to 150mm, just below a node. Leave the two top leaves, remove all other leaves and shoots. Split 12mm down the stem. Only one scion is taken from the middle of each shoot from the previous spring's growth. A pair of nodes is selected. Cut above and below these nodes to retain as much internode length as possible. Break or cut off any buds. Remove the leaves and all of the petioles from the scion by gripping the petiole close to the stem and using an outwards and downwards action to snap it off. Cut a 12mm long wedge at the bottom end of the scion and fit it into the rootstock. A whip graft may also be used. I wrap the union with standard grafting tape and the upper part of the scion with clear plastic food wrap. Laboratory film may be used to wrap the union and the scion. The plants are then placed in full sun. When new buds sprout on the scion the coverings are removed or the laboratory film is left to degrade. These plants then need frost protection through the winter and are re-potted in early August into 200mm pots. I use the same mix for re-potting as for seed sowing.