It is rather well known that the color of flowers on Hydrangea depends upon the pH of the soil in which it is planted. Low pH in the soil means blue flowers and high pH means pink. Here is a quote from the Texas A&M site on Hydrangea: Sometimes a single plant may have shades of both pink and blue at the same time due to varying pH in the soil around the plant. http://aggie-horticulture.tamu.edu/county/smith/homegardens/Shade/hydrangeas.html [Broken] Note that the flowers aren't colored a blend of pink and blue, but rather some flowers are pink and some are blue. Could you map the conduits in the plant by selectively altering the pH around individual roots? Does this mean that there is a conduit that goes directly from root to branch? If so, is this true of plants in general? I am thinking of Maple trees in particular. I have a Norway Maple in my yard with a single branch that still has green leaves on it while the rest of the tree is naked. What could cause that?