All Things Hydrangea

Well, not really all, but a lot about hydrangeas!  As we were cleaning shrub beds this past week, we realized how many different hydrangeas we have planted in the past few years, and what an impact they make on the landscape.  There are of course a myriad of hydrangeas, but for our purposes, we categorize them into five areas: paniculata types (primarily white blooming, upright with strong stems, some blooming later in the season), bigleaf types (those with blue and pink blooms), Annabelle types (those with primarily white, flattened blooms), oakleaf types (large, coarse growing types with very large oak-like leaves and great fall foliage color), and climbing types (woody vines with strong structural elements to accent buildings, fences, etc.).   Just about all hydrangeas provide blooms from early summer through fall, and though each type has its own specific care and maintenance requirements, following a few simple steps will reward any gardener with a great staple for the landscape.

We are particularly fond of the white flowering Hydrangea paniculata; this group of plants provide beautiful, big (8”-12”) blooms late in the summer through fall.  They flower on new wood, which allows them to be pruned in early spring, so the winter interest that the dried blooms provide can be enjoyed.  We recommend buying new, named varieties of this plant because the stems tend to be stronger and the flowers are larger and have interesting color twists.  ‘Tardiva’ is a great performing pure white selection that has an attractive, clean, upright form; this variety can also be grown as a small tree of roughly eight feet tall by six feet wide and is perfect for small garden areas.

‘Limelight’ is a newer introduction similar to ‘Tardiva’ in form but with limey-green blooms that appear a month or two earlier in the summer.

A fantastic new winner in the paniculata group is the knockout ‘Pinky-Winky’;  the cute little name belies the robust, fast growing hydrangea that has huge 16” blooms that are pink near the bottom and bright white at the top.  This is a plant that will stop a gardener in his or her tracks, and always elicits the question “What is that??”

A long time favorite with any home gardener is the Annabelle hydrangea, Hydrangea aborescens.

   ‘Annabelle’ reliably provides greenish white to white flowers of sometimes 10” across from mid- summer through September.  This plant also blooms on new wood, so it is best treated as a woody perennial and cut back almost to the ground in late winter or early spring.  Anyone who has grown this hydrangea loves the blooms, but dislikes the fact that the flowers often “flop over” due to excess weight, making staking an almost necessity.  Such floppiness can be partially alleviated by pruning the plant to the ground in winter and fertilizing lightly in May or June with a balanced shrub food.

Two new introductions to this plant group are stirring a lot of excitement in the nursery industry, but extensive planting will need to be done to find out if they live up to the “buzz”.

 ‘Invincibelle Spirit’ is a pink flowering version of Annabelle, and with its bright pink blooms, is the first of its kind.

‘Incrediball’ is a new Annabelle type that has enormous white blooms that are the size of a soccer ball!    While we are skeptical, the grower and introducer of this plant tells us that “Incrediball” has super strong stems that will amply support the awesome flowers.

The third group of hydrangeas popular in the Kansas City area is also the most problematic.  The bigleaf hydrangea, Hydrangea macrophylla, is the  group that blooms in shades of blue, pink, reddish, and light purple. The flowers are generally roundish and appear in mid-summer.  However, because this plant blooms on old wood, and Kansas City is in the northern limits of its growing range,  oftentimes flower buds (or even whole plants) are killed back to the point that no flowers appear in the bloom season.  There are dozens of interesting varieties in this species, but for our area, “Nikko Blue”  has been about the best performer through the years.

  Recently, exciting new introductions that bloom on new wood have exploded on the market, making it easier for those gardeners in the northern half of the U.S. to enjoy these hydrangeas.  “Endless Summer”, “Blushing Bride”, and now “Twist and Shout” all show promise to have the big blue or pink blooms landscape lovers have been craving.

Unfortunately, the Greenleaf Garden Services gang has been largely disappointed with the performance of this plant group.  We have encountered a great deal of dieback through the winter, and underperformance in the succeeding spring and summer months.  The plants to us just seem anemic and weak, though we are trying various fertilizing and siting ideas to see if we can help them live up to the hype. With that in mind, certain cultural practices will help bring success with any hydrangea in this group.  Planting the bigleafs where they can get 5-6 hours of sunlight without being exposed to burning hot afternoon sun is ideal (too much shade really reduces bloom); fertilizing with a 1-3-1 ratio fertilizer helps too but don’t fertilize after September so the plants can have a chance to harden off before winter.  Also, watering too heavily can reduce bloom and produce mostly green leaves; allowing the plants to stress slightly will encourage bloom (this is true of most woody plants).  If you are fortunate enough to have a good blooming bigleaf hydrangea, you can control the color of bloom by adding aluminum sulphate for blue blooms, and dolomitic lime and high phosphorus fertilizer for pink blooms.

The fourth hydrangea group is the Oakleaf hydrangeas.  This group is the author’s favorite because of its big, bold nature; everything about this plant is supersized, and its ease of care and reliable growth make it a “must-have” for any garden that has ample room.  Hydrangea quercifolia grows to about 6’-8’ tall, with a spread of 8’-10’- or even more; the leaves too, are large, reaching 8” long and sometimes 6” across, and resemble those of some sort of mythical red oak.  The stems of Oakleaf  are beautiful shades of brown and cinnamon, peeling and exfoliating to lend interest in the winter months, and its overall form lends structure, stability, and uniqueness to a large shrub bed or planted next to a  building.  Additionally, the fall color for this hydrangea is nothing short of spectacular, exhibiting shades of red, orange, and yellow on leaves that persist well into November or even December.  If you can find one, a variety called “Snow Queen” produces huge numbers of beautiful blooms, held wonderfully upright on the ends of branches, and there is even a dwarf variety called “Pee Wee”, which grows about 3’ x 3’ and is much refined in its growth and flowering.


The flowers of Oakleaf are probably the least important aspect of the plant, but can be quite wonderful;  growing up to 12” long, the panicles of flowers start out a bright white, and with time turn a beautiful pinkish red and finally brown.  If you have a large garden space that needs a great plant, consider Oakleaf hydrangea—you won’t be disappointed!

Last, but certainly not least in consideration, are the climbing Hydrangeas.

 This is truly the aristocrat  of flowering vines; unlike vines like Clematis or Virginia Creeper,  climbing Hydrangea forms a strong, three dimensional structure with interesting branching and exfoliating stems that offer year round enjoyment.   This is a large vine that climbs via rootlike structures, and can grow to a height of 60’-70’!  Because of its mass and almost shrublike appearance, Climbing Hydrangea can be used to cover large structures or even eyesores like rockpiles, etc.   However, its unique beauty will demand the gardener place it in a prominent location.  This plant grows quite nicely in sun or shade, but in difficult sites, or windswept areas, a northern or eastern exposure is best.  It has beautiful, bright green leaves, and cinnamon colored stems that peel as they mature, and in June-July, Climbing Hydrangea produces large 6”-10” flat topped white flowers that are truly magnificent.  Climbing Hydrangea is relatively slow to establish, but new container growing methods are enabling landscapers and home gardeners to enjoy this star performer with far greater success than was common 25 years ago.

There is another climbing vine known as Climbing Hydrangea, but is not really a hydrangea species.  Japanese Hydrangea Vine, Schizophragma hydrangeoides, is very similar in appearance, but lacks the strong three dimensional branching that characterizes its Hydrangea cousin, and it blooms somewhat later in the season.  To the untrained eye, the two types are very similar, so if you have room for only one in the garden, choose the true Hydrangea anomala petiolaris; otherwise, opt for both and have two unique and beautiful vines for your landscape.

Remember, Greenleaf is always available to help you find the perfect spot in your garden for new and exciting plants!!