The Best Panicle Hydrangeas

Find out which panicle varieties are so amazing you’ll never want to plant a bigleaf type again

There is no denying the wow factor of thepanicle hydrangea , especially when it ’s in bloom . The flower truss are in - your - face big , averaging 6 to 8 inches long , but they can be much bigger . Even better is that the racy blooms sit atop stalwart branches during the dog daylight of summer , when other shrubs have end up their show . Panicle hydrangea ( Hydrangea paniculatacvs . , USDA Hardiness Zones 3–8 ) is a great old - fashioned bush . I understandably remember having to sidestep under a huge canopy of blooms while present newspapers as a boy . I ’ve seen a unnumerable act of different panicle hydrangeas since my paper - route twelvemonth — a testament to their dependableness and popularity .

Panicle hydrangea is undergo a renaissance of sorts , with a plethora of sweet cultivars making this vintage shrub relevant again . The inflow of new cultivars in the 1990s , as well as the obvious similarity among some cultivar , fueled my interest in begin a plant test in 1999 . Let ’s be honest : Comparing the flowers can be like star at a Magic Eye stereogram and look for the hidden picture to appear . How distinct are the plants , really ? Are the new cultivars improvements over the old one or just more of the same ? I knew that , by constitute the cultivar side by side , their similarities and differences would become clean — and , boy , did they ever .

How we treated the hydrangeas

Over the past 12 age , we ’ve evaluated 25 cultivars of panicle hydrangea at the Chicago Botanic Garden ( CBG ) . The initial trial included the traditional offering of the day , such as ‘ Floribunda ’ , ‘ Tardiva ’ , and ‘ Unique ’ , as well as some cultivar from Europe that eventually became available in the United States . In the last few eld , we ’ve kept the trial current by summate new debut . We grew the flora in their pet scene — moist , well - enfeeble soil in full sun — although most would also tolerate partial spectre . We shop them on ornamental qualities , cultural adaptability , winter robustness , and disease and pest resistance . The goal is to determine , through scientific evaluation , which flora are superior . Shrubs , like panicle hydrangea , are evaluated for a minimum of six years in CBG ’s Zone 5b garden .

The top-performing panicles

Because of its name , I expected‘Big Ben’to have Brobdingnagian flowers , but they were fair average compared with those of other cultivar . I was , however , over the moon when I saw the unexpected transmutation of the blooms from creamy white to cryptical fuchsia . The color of the open , weblike panicles continued to get better with age , a rarity in the plant world .

Where ‘ large Ben ’ is a bit of a misnomer , Angel ’s Blush ™ (‘Ruby ’ ) is a name that is maculation - on . The deep red stems foreshadow what ’s in store for the colour of the bloom : The whitened florets blush pink come summer solstice and then bit by bit darken to red by midfall .

‘ Dharuma’was the earliest hydrangea to blossom at the start of summertime and is the smallest of the hydrangea we grew , making it perfect for undersize gardens or container . Held on beautiful red root , the diminutive , lacy white flowers eventually age to deep pink . Because of its behind - growing , compact riding habit , this cultivar needs only a twinkle clip in give to take out pass blossom .

Quick Fire ™ (‘Bulk ’ ) is competently named for how rapidly the white flowers switch to pink in midsummer , top out at a dusky rose by late summer . Like ‘ Dharuma ’ , which is one of its parent , Quick Fire ™ boasts deep red stems and an former bloom metre . While it has a compact habit , Quick Fire ™ has perpendicular stems that occasionally shoot up pointer - straight in summer . The natural inclination is to prune back these errant stems , but resist the urge because they bear late - season efflorescence . Panicle hydrangeas typically have openhanded , dark green leafage with no significant fall color , but the leaves of Quick Fire ™ reverse orangish when ice chest temperatures set in .

It was observable from the start that there was something special aboutLimelight ™ (‘Zwijnenburg ’ ) . The impertinent chartreuse vividness and Rubenesque plumpness of its flower clusters set it apart . I am still in awe of its brassy flowered show and beyond impressed that its stem are unassailable enough to entertain up the rotund blossoms . In the trial garden , the serendipitous flowered collocation of overstuff Limelight ™ with noble ‘ bountiful Ben ’ was brilliant . It ’s hard for me now to think of get one without the other nearby .

‘ Little Lamb’looks like the kid brother of Limelight ™ but with creamy blank prime . Its embonpoint panicles are jam - packed with the smallest florets of all , which are less than an inch wide . I ’ll fight the impulse to compare the fluffy flower to frolicking lambs , but the doctrine of analogy is an honest one . Like Limelight ™ , its jazzy floweret gradually rick pink by early fall .

‘ Unique’is a giant — the tallest cultivar with the large flower truss . I think of this cultivar as a garden classic ( which is not just a gracious way of say that it ’s honest-to-god ) . It has been around since the 1970s , but that is because it has a solid repute for vigor and reliability . ‘ Unique ’ is the progenitor of many modern cultivar , such as ‘ Brussels Lace ’ , ‘ Burgundy Lace ’ , ‘ Greenspire ’ , Pink Diamond ™ , and ‘ White Moth ’ ; interestingly , in our trial , it outperformed all of these cultivar .

What you need to know about panicle hydrangeas

1. They are hardy

Panicle hydrangea are considered the most inhuman Oliver Hardy of the mintage . They are reliable shrubs or small tree that need minimal fuss for success . Their stout , blood-red brown branches are vertical to arc , sometimes becoming give in under the weight of the tumid flower . A tiptop and width up to 15 foot is possible , but something cheeseparing to 6 or 8 feet tall and all-embracing is more common . Due to their size , panicle hydrangeas are usually harness out for small gardens ; however , with judicious pruning or by opt a lowly cultivar , such as ‘ Dharuma ’ or Quick Fire ™ , anyone can enjoy them .

2. Pruning doesn’t affect bloom

Unlike bigleaf hydrangeas ( H. macrophyllacvs . , zona 6–9 ) , panicle hydrangeas do n’t take care being trim . I advocate cutting the plants back by about one - one-half of their height before the leaves issue , typically in early springtime — although this is n’t necessary if you have room for a big flora . We initially cut due to place limitation in the tryout bed , but the improved wont and performance after pruning boost us to do it regularly . The chart below reflects the size of the hydrangea with annual pruning . Panicle hydrangeas ( unlike many bigleaf types ) bloom on raw Sir Henry Wood , so pruning will not dilute flower production and may actually increase the sizing of the flowers . Contrary to some news report , yearly pruning did not encourage long , weak stem that could n’t bear the heavy flower . With the exception of ‘ Dolly ’ , all the cultivars were warm enough to hold up their blooms .

3. Flower type and size vary

The blooms of panicle hydrangeas are a mix of frothy , fertile floret and showy , sterile floret . The showy florets , variegate in size and quantity by cultivar , cater the long - survive bloom show , which is enhanced by a metamorphosis from lily-white to varying shade of pinko . The trend in breeding , not astonishingly , has been to intensify the pinkish color of the aging prime . I use the term “ lacy ” and “ mop ” to mark between the two prime types of panicle hydrangea . “ Lacy ” pertain to an undefendable panicle with showy florets interspersed among the fertile floweret , whereas “ mop ” indicates an overabundance of showy florets with fertile floweret veil beneath .

4. Watch the pH—but don’t worry about deer

Our soils at the Chicago Botanic Garden lean to be alkaline , which I found may cause foliar greensickness in panicle hydrangeas , peculiarly in raging , dry weather . In warmer climates , consistent water will secure healthier foliage and stronger flower production . Panicle hydrangeas are tolerant of urban consideration and are largely unbothered by pestilence and diseases . While the mould impedance of some cultivars is often gasconade , we never observed powdery mildew on any of our plants . And although cervid love bigleaf hydrangeas , they tend to be less concerned in panicle type .

5. They have some winter interest

I ’m not nutty about expound on a plant ’s winter character , but I do n’t agree with naysayer who opine panicle hydrangea has no winter interest . The attenuated tan flowers allow for a bit of color and structural pastime , especially when rim with frost or covered in snow . Being a slothful nurseryman at kernel , I prefer to leave behind them on until spring , when I ’m cut the branches back anyway . It ’s playfulness when the crispy panicles lose it off and roll through the garden like miniature tumbleweeds .

Panicle hydrangea trial results

Richard Hawke is plant evaluation manager at the Chicago Botanic Garden in Glencoe , Illinois .

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