PROBLEM TO BE SOLVED: To provide a method for retaining plants for a long period, in plant vegetative propagation.SOLUTION: The method for retaining plants for a long period includes performing plant vegetative propagation, using trehalose, for instance, a trehalose-containing culture medium. The method is suitably applicable to vegetative propagation of general plants which cannot retain transformation present hereditary characteristics in a progeny system by seed multiplication, due to hereditarily unfixed property or self-incompatibility of, for instance, a gene-recombination plant such as a gene-recombination ornamental plant.
