Tanguy,

These are great photos and an excellent representation of harvesting canna seeds from hybrid canna cultivars. As you may know, C. Grande is a hybrid cultivar and not a specie canna. Therefore the seed produces offspring that are all somewhat different (DNA) from its breather. Each seedling must be considered simply an unnamed seedling of C. Grande. Although I do not recommend doing so, you can name each of these offspring and by dividing each plants rhizome produce your own new cultivar. Remember that there are rules for naming a new cultivar and it cannot be any previously used name and must comply with the International Rules of Nomenclature. Unfortunately most avid gardeners do not understand this simple fact and it causes a multitude of issues regarding our canna cultivar community.

The real beauty in what you have done, at least technically, are these canna offspring are unique in some small way from any canna ever produced even though we often cannot visibly observe any difference from some other cannas.

Regards,

Kent

Beautiful! I grow cannas from seed too and get a mixed group.