IMHO, they likely have to reach a certain size before you can get the full value for the color--at least 2 or 3" possibly more. most all the spectacular pictures of this species that folks see are obviously of large diameter mature trees. i grow a number of eucalyptus tree species outdoors (sadly not this species---it is definitely tender to any significant hard frost) and FWIW the colorful bark feature on my trees is generally not shown on seedling trees but takes several years to develop.

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

I know it's late...... but have I just been flashed????LOL M

I used the search box at the top of the page to search for "oak bark" and got a lot of hits, and several on the first few pages asked the same question. Hardwood bark and the wood of any species decompose much faster than fir or pine bark, destroying the soil structure and acidifying the mix. I don't know about redwood, but their stronger and long-lasting fragrance makes me suspect that they'd change any soil's chemistry. That's about as much as I know, but you might try a search to see if someone smarter than me posted a better answer.