Sow the seeds in flats and place them out of doors or collect the seed, place in damp perlite or other similar material, and store in refrigerator for 30 to 60 days prior to sowing. The pH needs to be adjusted to 5.5-6.0. The seeds germinate in 10-14 days and depending on grower's purpose may either be placed on a multiplication media or planted out in three to four weeks. Most asexual propagation is accomplished by taking vegetative cuttings although several of the species respond well to layering. Hydrangea macrophylla ssp.
Roots initiate in greater numbers at the node but develop in sufficient numbers elsewhere.
Three types of cuttings can be made from leafy vegetative stock material. The one to three node cutting should have some of the leaves removed from the lower nodes to prevent them from coming into contact with the rooting medium. This will also reduce the space required in the propagation bed. Do not trim individual leaves as this provides pathogens with easy access The lower nodes of the stem can be made into butterfly cuttings. This type of cutting provides a propagule with two eyes that will initially develop into a plant with two leaders.