Homegrown: Hydrangea Essentials

Lisa Slattery, Iowa State University, Linn County Extension Master Gardener, sent the following about one of Iowa's  popular landscape plants:

I love Hydrangeas.  They remind me of a truly old-fashioned and classic garden-scape.  Hydrangeas, originating from the Americas and East Asia are excellent choices for mixed borders, landscape and garden foundations, and specimen plantings.  They have big showy flower heads that range in many different colors and are essential for both fresh and dried flower arrangements.

 However there are several varieties available and you want to make sure you plant the right ones.  One question Master Gardeners hear a lot is: Why doesn't my three-year-old hydrangea ever bloom?  Probably because it's a big leaf Hydrangea ‘Macrophylla' like 'Forever Pink' or 'Nikko Blue.'  These usually don't bloom inIowabecause they bloom on old growth (or the previous year's growth) and our winters are too cold for this old growth to make it through and they usually die back to the ground – resulting in no re-blooms.  The foliage grows beautifully but no blooms occur. 

There are several big leaf Hydrangea cultivars that do grow well for Iowa gardeners.  Hydrangea ‘Paniculata' and ‘Arborescens' both bloom on new growth, are relatively trouble free, and should bloom every year once they are established in the garden.  I have several of these hydrangeas in my gardens.  The very popular ‘Endless Summer' hydrangea blooms in shades of blue, purple and pink.  ‘Blushing Bride' blooms in shades of white and light pink.  New cultivars seem to come out every year.  Several newer ones that I am growing include ‘Limelight' that has chartreuse blooms that turn pinkish as they age and dry, ‘Pink Diamond' a very soft pink blossom that is not as round a blossom but more pointed in shape as well as ‘Unique' which is very pretty white fading to a blush of pink.  It has been my experience that not all of the Hydrangeas actually bloom in the colors promised in their descriptions.

 Another Hydrangea that grows well inIowa is the smooth hydrangea ‘Annabelle' with huge creamy white flowers that bloom from June through September.  ‘Pee Gee' is another cultivar that will bloom throughout the summer.  A less popular but most impressive hydrangea is the oak leaf hydrangea or ‘Quercifolia' cultivar.  This one has leaves shaped like oak leaves, white blooms and foliage that turns burgundy in the fall.  Try ‘Snow Queen' if you'd like one of the oak leaf cultivars.  There is even a painfully slow growing climbing hydrangea cultivar available which can reach heights of 30 feet if you are very, very patient.

 All hydrangeas except the oak leaf hydrangea like full sun and need sun to bloom.  Some afternoon shade is perfect since Hydrangeas don't like to dry out and will wilt quickly in hot dry conditions.