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.