Loolie, I wonder if you were ever able to learn more about the root system of your eucalyptus citriodora. I also have a citriodora that's about the same size as yours and am trying to find out how deep the roots might go (in terms of watering, in my case). We're in an extended drought in California, the opposite of your weather when you wrote your message more than 5 years ago. And our soils are likely to be very different, which affects root structure, from what I've read, so even though our trees are the same there could be big differences in their root structure. Nevertheless, I'd be very interested to know what you eventually found out and what happened with your tree. By the way, I didn't find your question metaphysical, per one of the replies, nor unreasonable as others seemed to imply. So, again, if by any chance you ever run across this message, I'd love to hear your update.

Drew, as it happens I was WRONG, WRONG, WRONG. It is not a Corymbia at all, but Eucalyptus cladocalyx (sugar gum). Apparently it is common in California, but being native to South Australia, I've never seen one. I checked it with my expert friend Gus from Spain on Hardy Eucalyptus Board. The capsules are actually too narrow for C. maculata, even though they are the same general shape. Apparently the buds of sugar gum grow in clusters of 7 or more from a single point, which then becomes a peduncle as it grows out from the stem. The bark is also not a perfect match with C. maculata, being not as closely mottled. Here is a useful link:http://bp2.blogger.com/_3uQiDL3c53s/SJNAmFMNTRI/AAAAAAAAAzM/9qSdoNoarn4/s1600-h/GIT_Forestry_Eucalyptus_Identification_Sugar_Gum.jpg

There doesn't seem to be an awful lot of information in regard to your query. This may be because eucalypts are so readily available here and also quite cheap. More gardeners would propagate from seed than to attempt cuttings I think. I found this one article that may be of interest to you. I hope it is. Just type in guest as username and also as password. Cheers, Dee. Here is a link that might be useful: Rooting Eucalyptus globulus

I run an online store seeling Australian seed, the ten fCorymbia Ficifolialat ovate khaki seeds about 6mm long would have to be the Corymbia Ficifolia. Euc sideroxylon rosea and Euc leucoxylon petiolaris are quite similar as in being small and red and black although the E. sideroxylon is a little more orange than red. (the black are the seed in both these the red or orange is only chaff) Eucalyptus caesia seed is about 2mm and dark in colour and a little dimpled looking. Thats about all I can tell you from the details you have. Hope it helps a little. All these growing very easy with no pre-treatment. Here is a link that might be useful: Australian Seed and Plant