Hydrangeas are vibrant, long-lived shrubs that produce varied and beautiful blooms throughout summer and into fall. They are incredibly versatile, available in a range of sizes, forms, and flower colors, they can enhance every garden. Sizes available range from ones that grow two to three feet tall and wide, while others are capable of reaching 15 to 25 feet in height with a spread of 10 to 20 feet. Hydrangea flower colors can be pink, purple, blue, red, white and shades in between. This large group of plants are easy to grow, tolerant of most soil types, grow in sun or semi-shade and require little maintenance. Hydrangeas can be planted singly or in groups, in flower beds and borders, foundation plantings, and even thrive in containers.
There are six species of hydrangeas that are commonly grown in American gardens: bigleaf (Hydrangea macrophylla), the most common; smooth (Hydrangea arborescents); panicle (Hydrangea paniculata); oakleaf (Hydrangea quercifolia); climbing (Hydrangea anomala ssp. Petiolaris); and mountain (Hydrangea serrata). Most are natives of Asia, but some are native to the United States. Each of these requires a different amount of sunlight, and has various colors and blooming times. Within these species there are hundreds of cultivars and these deciduous shrubs start blooming in summer and continue up to frost. New cultivars of hydrangeas are being introduced every year.
Characteristics -
Hydrangea macrophylla
Color: White, pink, blue, purple or red
Bloom time: June to October
Hydrangea arborescens
Color: white to pink
Bloom time: June to September
Hydrangea paniculata
Color: white to pink
Bloom time: July to September
Hydrangea quercifolia
Color: white to pink and red
Bloom time: July to September
Hydrangea anomala ssp. petiolaris
Color: white
Bloom time: May to July
Hydrangea serrata
Color: pink or blue
Bloom time: June to August
For a brief explanation on the meaning of genus and species: In the plant kingdom, genus is a taxonomic group covering more than one species. The species name relates to a sub-group of one or more plants within the genus. These plants will share similar characteristics with each other.
While answers to the number of species of the genus Hydrangea vary, worldwide there are approximately 70 species. The native range of the genus extends from southern and eastern Asia (from Japan to China, the Himalayas, and Indonesia) and North and South America.
What is the difference between a cultivar and a variety? Garden writer David Beaulieu says, “A cultivar, short for cultivated variety, is a plant that is propagated through human intervention to develop a desirable characteristic and ensure it retains the characteristics of its parent plant. A plant variety is found growing and reproducing naturally in the plant kingdom. It varies from its standard species in some way as a result of natural evolution.”
Should you prune hydrangeas? - Yes and no! Some hydrangeas flower on old wood, some on new wood, and newer cultivars flower on old and new wood (blooms on old wood, meaning the flower buds form on stems that grew the previous year). So it is important to prune them the correct way so as to not detrimentally affect their flowering. Hydrangeas that bloom on old wood, including bigleaf, oakleaf, and climbing hydrangeas, produce flower buds during the later part of the summer season. If these shrubs are pruned in the fall, winter, or spring, the buds will be removed before they get a chance to produce blooms. And the way you prune the different hydrangeas differs. There’s still more to come in the next article.
Until then, in closing - there should be a hydrangea every garden!