those are WHITE 3 gallon pots that I place inside of a BLACK 5 gallon pot in order to get the picture... otherwise the white pot reflects all the light from the camera flash and messes up the picture
I read a tip guide found on Royal Queen Seeds website I think, on taking photos of canna and it suggested using white as a backdrop for good pictures. Its def hard to work with though because of light reflection. Nice looking plants. Like the symmetry of the structures you are able to keep with your training.