Wednesday, March 6, 2013

Panicled Hydrangeas For A Landscape Punch

My arms are still numb from all the shoveling I had to do at home prior to shoveling here at the gardens.  Sounds like we received a good 10" or so since yesterday morning.  Mark S. and I shoveled the front of the Parker Education Center while Larry and Bill O. did most of the remaining snow blowing and other clearing duties.  Thanks to Dick H. for all his snowplowing assistance at the Horticulture Center parking lot this winter!  We had a busy day for a Wednesday with many volunteers helping out at the Horticulture Center.  Kay and Pat R. continued work on processing plant sale labels and Janice came in a bit later to keep them on track and work on some other projects.  Dr. Gredler did more painting and Pat continued work on his giant obelisk project.  Vern is catching up with bench re-sealing efforts and we also saw Gena, Sue M., Gary, Dick H. and many others.  Larry later worked on some equipment and I finalized all my seeds for travel to their destinations tomorrow.

I'm featuring the panicled hydrangea (Hydrangea paniculata) today which is a wonderful shrub for the sunny or partly sunny landscape (see top photo, unknown variety at Olbrich Botanical Gardens).  Ten years ago, the variety 'Pee Gee' was the "go to" option for this tough shrub and was known for large, white flower clusters in the summer that would later transition to pink in late summer and amber by fall (see photo directly above).  Essentially the flower interest extends from July well in to fall and also has some winter interest as long as the flower clusters stay attached to the stems.  How many flowering shrubs feature 4+ months of flower interest?  Most of us are familiar with the smooth hydrangea (Hydrangea arborescens) with 'Annabelle' being the most popular variety of this species.  This species is quite shade adaptable and will tolerate a wide degree of soil  and lighting conditions.  Understand that hydrangeas are not drought tolerant and become "thirsty" very quickly and will let you know when they need a drink.  The panicled hydrangeas are no exception and really perform best in full sun conditions in moist, well-drained soils with a mulch layer for moisture retention. The mature size of any selection should be taken in to account when considering desired and proper placement.  With mature sizes for most varieties being in the 8'-12' range with a similar spread, they require a lot of "real estate" in our landscapes.  However, recent developments have focused on reduced size or compact varieties that will stay in the 4'-7' range and have more versatility in the average home landscape.  There are many compact varieties offered now and their reduced size makes them perfect as foundation plants, border components, focal points and general interest plants.

The variety of panicled hydrangea (Hydrangea paniculata) above and in the next two photos below is 'Limelight' which is promoted for extremely lime summer flowers that will ultimately still transition through a white, to light pink, to amber by November.  I use  'Limelight' as just one example of how important the flowers of the panicled hydrangeas have become for breeding and selection work.  There are now dozens of varieties that will emphasize flower characteristics like an earlier start to bloom time, significant lime coloration, strong pink highlights, etc.  I've included just a smattering of available varieties below and in some cases, I've included both the early summer and late summer colors for the same varieties.  Understand that all of these varieties will exhibit some degree of the "color transition" as I call it with lime, to white, to pink, to amber brown although the intensity and duration of those stages is what is of primary interest with each selection.   Some varieties feature more open flower panicles while others are quite dense and/or elongated (see 'Dharuma' versus 'Phantom' below as an example).  While some cultivars look entirely different, many look very similar.  Regardless, the panicled hydrangeas should enjoy significant use in our gardens as their true merits are appreciated when their happy establishment is accommodated.  These hydrangeas will bloom on both old and new wood and can be pruned during the dormant season as needed.  However, avoid severe rejuvenation if possible as the branching response can include long, slender stems that become floppy with the summer flowers.  Select varieties for acceptable sizes and consider light, thinning pruning on an annual basis (every winter) to keep selections in scale as desired.  Regardless, with so many selections available at your local garden center, there is a panicled hydrangea (or two, or three, ...) for all of us out there!
'Limelight' summer flowers
'Limelight' at Cantigny Garden (Wheaton, IL)
Pinky Winky ('DVPpinky') in summer
Pinky Winky ('DVPpinky') in late summer
Quickfire ('Bulk') in late June
Quickfire ('Bulk') in late summer
'Bombshell' in summer
Sweet Summer ('Bokrathirteen') in summer
'Phantom' in summer
'Phantom' in late summer (Chicago Botanic Garden)
'Little Lamb' in summer
'Little Lamb' in late summer
'Silver Dollar' in summer
'Silver Dollar' in late summer
'Dharuma' in mid-summer
'Dharuma' in fall
Angel's Blush ('Ruby') in fall at Longenecker Gardens
'Pink Diamond' in August at Olbrich Botanical Gardens


Ken Nicely said...

Hydrangea have always been part of a certain flower family thats always been in my garden, odd how other people are also so fond of them!

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Tree Pruning Brooklyn

Catherine said...

Lovely pictures! Question: I have 2 Little Lambs, and neither are upright, which really takes away from the look and functionality of the plant in my garden. Do you have hints for pruning them to help them look more like your picture? When I purchased them, they had one 3-4 cm thick by 15-20 cm tall stem in the middle, and I am wondering if I should cut that back and start over.


Beginning Gardener

Mark Dwyer, Director of Horticulture, Rotary Botanical Gardens said...

Hi Catherine,

We prune our panicled hydrangeas in winter and in some cases, will prune them down to 12" tall stems. They will still flower on new wood and you'll see a surprisingly vigorous response with new shoots coming up. Keep snipping away undesireably angled side stems and encourage the more upright growth. In essence, don't be shy about a severe "haircut"! Good luck.


Victoria Bruffey said...

Help! I planted two Limelight and one Little Lamb 6 years ago in a shady east end of the house. The info card indicated shade! They flower but not a lot and the stems are severely droopy. Not full, upright or bushy with lots of leaves. Mine have never looked anything like the photos I see. I think the tag is wrong and they should be in sun???