According to the United States National Arboretum, there are approximately 23 species of Hydrangeas. Only five of these are cultivated in the United States. These species are Anomala, Arborescens, Macrophylla, Paniculata, and Quercifolia. Depending on the species, hydrangeas can be planted in just about any location. No matter what species you choose, you can guarantee that the hydrangea will provide long-lasting blooms in the garden.