Some riffs:

(A.) I planned on pruning these Hydrangea late in the spring. Yes - textbook, you prune them in "late summer after flowering" as they flower on old wood...but...I think that idea must come from the practice where you are just blindly cutting the plant back? As if, you cut the plant back hard "after if flowers," late in the summer, and this gives the plant enough time to push out some new growth before the season ends, on which of course, there will have formed flower buds for the next season.
But this is Buffalo, NY and the traditional, old-school Hydrangea macrophylla doesn't often have its primary flower buds survive the winter. More often than not the flower buds are killed off by winter and early spring cold.
AND...I don't know about you, but I think we appreciate the form and color of the faded Hydrangea flowers well into the fall and early winter...so we don't cut them back, we don't deadhead.
Furthermore...I believe a good portion of the macrophylla offered in the nursery trade locally are what we would call "rebloomers" - these contemporary cultivars put out flower buds on both old and new wood and therefore, if the buds on old wood are killed off over the winter the Hydrangea still will flower later in the year on new wood.

(B.) So...I'm pruning now (this morning), in late winter/early spring. I am not cutting back or reducing the plant in size, I'm essentially just cleaning. These Hydrangea get filled with deadwood pretty quickly. And, seemingly, as a rule, anytime anyone does prune them, they just top branches (I suspect in late summer!) about 8" off the ground and it leaves behind this mat of dead stubs that clutters the base. When cleaning up in the springtime - since we don't deadhead -  the flowers from last season need to get cleaned up ("need" meaning, for visual reasons; for order) - and often the snow and perils of winter have broken a good portion of the branches still holding on to last seasons flowers...

(C.) - I suppose it possible, at times with MATURE plants, a good hard rejuvenation prune - in late summer - may be helpful to give them a fresh start and a reason to vigor (not really a verb...but...).

Method
This was a sizable project (today's: depicted in images above) taking about 90 minutes in deep focus to prune this cluster of 7 plants. In this garden, there are still another 20 to 25 macrophylla to prune. I performed the work with earplugs in, something I like to do so as to keep me in a meditative space. I need standard hand pruners only,. I've been using Coronas this season, not Felcos. $24 a pair vs $60 and the same cut as far as I can tell. I go through 2 or 3 pair a season, so, it's relevant.
I start at the tips closest to me combing through one branch at a time. If it has a old flower, I cut it off to the next bud. Many branches won't have a flower but a large pointed terminal bud. Chances are its cooked from the winter, but you can't really tell for sure, so I leave it. Any breaks I take back to the highest bud. I go down each branch and eliminate the dead laterals. I get down to the ground and I clear out all those dead stubs and the number of full length dead branches. For the most part, this is it, just deadwooding, but every so often there is a crossing branch I take out or "other things" that I don't like - but this is very minimal.

​

Today.
Weeping Mulberry doesn't seem to find its potential around this region but, elsewhere, I see it as a well pruned winter sculpture.

I have a couple that I am able to work with but there is always a "conflict" with the client - they can't help but take trimmers and pruners to it and hack it back during the summer months when it grows super fast. The aggressive and control oriented pruning always leads to the heavy production of buds and shoots; 18 months later the tree is a mess.

With the two I worked with today...we are starting with one of those messes.

Method:
One can't cut at a Mulberry heavily - it will just cause a violent bud/shoot reaction. At the same time, we're starting with a mess - there are 1 to 2 inch branches crossing each other throughout the body of the crown. So, I allow myself two to three "big cuts" on each tree but keep them deep in the interior where they MAY be less likely to push buds (my speculation as there is little sun in there and everything on the inside is already dead) and only one "big cut" on either of the major skeletal branches. We'll deal with the fallout from this, if there is any, later. After these big cuts, I only cut out deadwood.

End Note:
Every pruning job like this, regardless of the species, is moves based on speculation of how you think the plant/tree will react - it's an art, but it may be best to use the term "informed practice" before we turn loose someone's creativity.

"For me, a good plant fulfils a specific function in the garden, and does it well."

In the literature
I read of plants being used as
​Function, not poetry.

In the world of production
Plants may function by
Sequestering carbon or cleaning the air.
Plants may be used to draw lead out of the soil -
Stabilize the bank of a stream or river -
Break the wind, fix nitrogen, or protect
The topsoil of a farm that lay fallow.

But in the garden
Plants are not technical objects.
Plants may “do” something
They signify, make allusions, affect
But they don’t function.
(I am drawn to the word “Gesture.”)

Beware of false prophets
Who write of plants that function.
This is engineering speak
Not poetry, design, nor gardening. 

Bird, Richard. The Illustrated Practical Encyclopedia of Pruning: Training & Topiary. Lorenz Books, Leicestershire, 2012.
IBSN-13: 978-0-7548-2466-4
IBSN-10: 0-7548-2466-7


While my recent work has been interested in the literature on shearing, hedges, and simple topiary, these practices fall into the craft of pruning. My interest, or criticism, has been taking the position that “pruning” - as I see and hear it spoken of and identified with by horticultural enthusiasts around me - is a specific “register” of interest that attaches itself to a larger belief system about the landscape, nature, plants, art, work, knowledge, and history. We may go as far as to say “Its a power form.”
I believe all our “pruning” practices find their origin in fruit production, the management of boundaries and property lines, and the production of wood and timber. The ornamental only emerges from these as aesthetics.
​What has captured me about Bird’s book on pruning is its full inventory of all the different practices we can name in the training of plants. I thought it a good idea to list this inventory in my notes as it gives a good context to the field of training/pruning plants and very much diminishes the great importance ornamental horticulturists put on their pruning practice. Or, with an inventory, it frames the pruner/landscaper as a very limited field of practices.

Pruning is a poetic movement.
The truth of the practice reveals itself only in practice.
It is the practice itself that is concealed -
The novice is paralyzed -
Their action aims to make form into a previous image,
Where as the poet only moves to articulate the practice.

The practice is the truth.
​

To maintain trees at a certain size
For it to maintain "that quality" of a tree
It has to be pruned from the inside
Following more of a methodical process 
That moves in an understanding of growth.
But first
In what may take a couple years -
An architecture of branches must be created.
​Then one can return on intervals
And make cuts repeatedly
In method.
Part of the architecture is about
creating a structure that can be returned to again and again
and easily reduced to its managed form.

One's cuts are much lower than if you were approaching from outside the crown.
From here growth sprouts and grows.

You can't teach pruning.
There are some principles -
You must know how growth and buds form in reaction to cuts -

It is a poetic.

I had my shears in hand Monday, ready to go through all the garden's formal plant elements and tighten them up - but as I stepped to the first plant I said to myself, "I don't need to spend an hour doing this now." It is/was early May, mid spring, and the new growth is just forming. This is the time to "shape" not trim. By this I mean, (this being a garden I was tending for the first time) it was a time to make heavier, deeper shear cuts to "address geometry," not manicure. Early in the season, plants will more aggressively push new buds in response to heavy pruning cuts, so this is the time for some deep disciplining. "Trimming" and "manicuring" is more of a maintenance practice to be done anytime. But this type of maintenance shearing is light and more about an immediate presentation of the garden than making the garden.

“I don’t know why my Hydrangeas don’t flower” is one of the great conundrums that are handed to me by clients. As with all things, I never know exactly, nor do I have an clear answer, I can only offer that coming to understand these things takes place in the process of experiencing and working with the garden. This question almost always comes while looking upon a Bigleaf Hydrangea (Hydrangea macrophylla). Immediately one asks how it may have been pruned, the gardens history and care, considers the soil, and how cold it was the past winter knowing that Hydrangea macrophylla often experiences tip dieback where you loose the flower buds to the winter’s cold. 

A week or two ago I ordered Michael Dirr’s latest edition of “Hydrangeas for American Gardens” (2020) to begin a little study on Hydrangea. I am finding them becoming so popular, even in my own preferences, that some study is a worthwhile investment. At least at the start of this, it was Hydrangea paniculata and its cultivars that I am most interested in.

However, a little tidbit caught me while reviewing Dirr's work on Hydrangea:
Bailey (1989a) provides climatic data for the native habitats that explain Hydrangea macrophylla sensitivity to certain extremes. Honshu enjoys more than 5 months of frost free temperatures. The mean low and high temperatures are 31 and 47 degrees F in January and 72 and 85 F in August, respectively…The conclusions are obvious: H. Macrophylla prefers moderate temperatures…(73).

Most of Dirr's writing on macrophylla is based on studies done at his University in Athens, Georgia and from research done in North Carolina. Even at those southern locations, some of the named cultivars he writes of as not surviving the cold are names I recognize as macrophylla cultivars in WNY nurseries. From this I leapt to: “All these Hydrangea I see that don’t flower - they probably just aren’t hardy enough to begin with.” So. I thought I would do a little research on the cultivars most readily available to me right now and find what research I could on hardiness data.
One key is understanding the “remontants” or re-bloomers. These bloom multiple times because they will bloom on this seasons new wood as well as older wood. A hydrangea that doesn’t bloom on new wood is dependent on old wood to over winter for its flower buds. When they are killed off by frost, no flowers. But with re-bloomers, the old wood can die back to the ground but still produce flowers that season on its new wood.  I believe most traditionally we think of Hydrangea macrophylla as a plant that "blooms on old wood." 


The Study:
Generally, and this is new to me, it seems that plant breeders characterize Hydrangea macrophylla as “undependable.” Thus my curiosity of "why is this such a commonly used plant in WNY?"
To disclose, this isn't the deepest research. A few hours. I made the best sense of things reading a couple blogs, Dirr's latest edition of "Manual of Woody Plants," Dirr's latest on Hydrangea's, and a few wholesale catalogs and nurseries I have here in the office. Here is what I have found on the cultivars:

1. ‘All Summer Beauty’ - Supposedly a rebloomer but noted as inconsistent in its reblooming by Dirr
2. City Line Series. ‘Berlin Cityline,’ ‘Venice Cityline,’ ‘Vienna Cityline,’ ‘Paris Cityline:’ German bread trademarked series. Dirr observes as being heavily covered in mildew in late summer and fall:  writes “I have immense doubts about their hardiness.”
3. Teller Series. Swiss breed. Dirr notes ‘Teller White’ being sensitive to late spring frosts in his Georgia garden. ‘Teller Blue’ - seen locally as ‘Blaumeise’ - is considered the hardiest of the series. Dirr writes, “Most Tellers are not very cold hardy.”
4. ‘Lady in Red.’ Dirr’s 2009 Manual describes this as having “superior cold hardiness,” which at this point, I think means, you are probably going to lose a lot of flower buds to frost and cold in the WNY area. But. I might like to give this a try. (For some reason I feel I saw it referenced as being ideal for container planting - which is how I will try it)
5. ‘Mystical Opal.’ Of the trademarked Mystical Series. Dirr writes of these as “bred for the florist trade,” and their use as pot plants - which I take to mean, these are the ones you see in the super market in one gallon containers. Does not appear that they rebloom. I don’t get the impression these are intended to be a landscape plant. However. I do see them in nursery catalogs.
6. ‘Pink Beauty’ also referred to as ‘Preziosa.” Each nursery I reference lists ‘Pink Beauty’ as a macrophylla however Dirr (2009) lists as as a synonym for ‘Preziosa’ which is actually a hybrid H. macrophylla x H. serrata. The species serrata seems to be getting a good amount of attention the past two decades because of its potential for cold hardiness as its native habitat is in colder, higher elevations.  This doesn’t necessarily translate to ‘Pink Beauty’ being hardier, but maybe.
7. ‘Tokyo Delight.’ This is listed as a macrophylla out of an Ohio nursery but Dirr lists this (2009) as a straight cultivar of serrata. 
8. ‘Nikko Blue. Dirr writes “May be somewhat of a rebloomer.” 
9. ‘Endless Summer’ and ‘Twist-n-Shout.’ First of the repeat bloomers, however, plantain Tim Wood writes of them as still lacking as flowers on new wood don’t bloom until very late in season. 
10. ‘Bloomstruck Endless’ is one of the most recently released cultivars. Cross of “Endless Summer,” which brought the first reality of a repeat bloomer to the market. My study on this seems to record the recent history of plant breeding. 2004 was the year ‘Endless Summer’ was introduced. This has since been improved with ‘Bloomstruck’ series of cultivars which I believe were released in 2014.

What I generally find in the literature combined with my experience is that Hydrangea macrophylla's flower buds, those on old wood, are most often probably killed off. A Hydrangea can be listed as cold hardy zone 4 (for example) but this just means the plant survives, it doesn't mean the flower buds survive. It seems that even all the new rebloomers and remontants, while exciting in concept, they generally seem to be written of as disappointing - however the most recent 'Bloomstruck' series appears to be the best yet and worth my experimentation. 
The thing with a rebloomer is, it becomes a plant that blooms on this season's wood, and thus later in the season, which means a shorter flowering season. It seems the recent improvements in Hydrangea arborescens are perhaps more worth exploring.

​Just some notes.   

Post Script. April 6th, 2021.

I have been watching the Hydrangea this spring. I can see that possibly the buds on the tips get through the winter as they have the opportunity to acclimate to the deep cold of winter. But now, the beds are starting to swell at the end of March, beginning of April. The inevitability of a hard frost here in early April - well - these swelling buds are probably most susceptible to frost/cold damage now. More so now than the first week of February. 

Some notes and bullets.

1. I was thinking about writing this morning. "Writing," not really as "I wrote an essay today," but writing as something one may do all the time, a part of one's process, taking notes, leaves of paper and notebooks, saving a thought for later, posting reminders. I have this "problem" - again, not "problem" to say "a bad issue with something" but "something I am working to solve" - all of the above mentioned items, scraps of paper, notebooks, folders, design notes, post its, etc - they end up scattered about, without connection. But all these pieces floating about are what I am working on here. 
2. I have a note I put up on the board - another mechanism to try and bind things together into wholes - that reads "Give the work form." I think I have heard writers or artists say this. To me it is a saying to recognize that the space of ideas, dreams, inspiration, and creation aren't material and that you have to make something - be it poetry, sculpture, drawing, or sound - so it can find its way into the real world. Give it form.
3. I have spent a lot of time in the past, mostly in the old days when I was in school, with people who wrote many exceptional essays. All of these people, who I was thinking of this morning, could sit down and write wonderful stories and accountings of everyday life. But I could only think of one person, my friend Allen, who, like me (or me like him), collected fragments and scraps..
4. This trajectory on writing started with yesterday's notes that collected on my kitchen table following a Zoom seminar I participated in titled, "Trends in Horticulture." I captured another thought or two this morning as I had coffee and wrote them on the same sheet of paper. 
5. During this seminar, I shook my head a lot. The speaker was someone my dad's age or a little older. His points on "trends" were about edibles, organics, native plants, naturalistic gardening, prairie and meadow gardens - and after a few hours of thinking about it I came to word this issue as - he was confusing a long term social movement he was inside of with a different social thing, a trend. 
6. Edibles, organics, natives, nature... these are all ideological positions one can occupy in their practice. There is a belief system that accompanies them. 
7. The movements listed above are not short term things. These have been growing, to the point of being mainstream, for thirty years. (While at the same time we can find many of their roots back in the arts and crafts movement)
8. Part of my irk over this has to do with the seemingly unrecognized conservative or right wing aesthetic of the local industry. We see this in what follows. I try to map this with neutral description. Please accept my short comings with it. 
9. When "nature" and "the natural" are talked about in the industry, the market, and literature, the words point to different emotions - the linguistic term "registers" might be used here - and someone in one aesthetic/emotional/ideological construct can project themselves into a position of power by using and occupying tender words to point towards their (the speaker) harder forms of making the world. 
10. On the "The Left," we might say you have environmentalists and "tree huggers" - who may express concerns over "The Bee Problem" with a flavor of guilt that we, as a civilization, are doing something wrong and bad, and need to stop out of ethical consideration over the value of the bees life. On the right, the concern over "the bee problem" may be equally intense. On the right one may find the valuable position of "The Conservationist" who will most everyday wake up in alliance with the "Environmentalist." The conservationist tends to have their position based in the protection of nature, protecting the bees as an important resource to everything we humans find important. We need the bees to pollinate the the fruit trees and the flowers we love, to keep everything in nature natural so it can be experienced and visited as something we value in life. These two positions are ideological opposites. (these are just rough sketches)
11. There is of course the basic opposition: One position sees humans in a struggle opposed to nature. Another opposite position sees humans as nature and inseperably assembled to it.
12. We also see an ideological division when "the landscape" is talked about as nature. On the right, it is imagined that when we make landscapes and gardens we "bring nature to the city." The left perspective - which is a very small minority of the everyday world I inhabit - sees "the landscape" and "the garden" as something man made, just as material as brick or glass in the city. 
13. From this point, we see a different relationship between how some speak of gardening and landscape as "art." I am not sure how to imagine oppositional positions here, but I imagine one opposition being "architecture and the landscape as part of art history." It is a monument of human culture. How we make the landscape today is in dialogue with all the landscapes and ideas of the past. This may include conversations about nature. Opposite to this, I think there are a lot of different separate positions. One word, so cliche in garden writing, "Whimsey" comes to mind. Or, maybe the way to think about the opposite of a landscape that is in dialogue with cultural history is a landscape that is in dialogue with the immediate moment. 
14. In some research on Hydrangeas yesterday, I was reading Michael Dirr's 2020 revision of "Hydrangas for American Gardens." I won't try to articulate this difference  as left or right, but it is definitely a different form of imagining. Dirr works back and forth from a number of "positions" - positions I will call "botanical science," "gardener," "commerce." On the one hand you will read pages and pages of dialogue about the history of different botanists attempting (the impossibility of) to classify, with specific name, all the different repeatable observed characteristics of thousands of Hydrangea around the world. And then in his next paragraph Dirr will write "occasionally nurseries will use the name..." to recognize the separation of the pure botanical sciences from commerce. The nurseries and agriculture, while full of their own knowledges as well, are not "University Science."
15. Dirr's work is beautiful to me. It helps inform my own work. But the thinking and work that happens in the Buffalo Horticulture Project is different and has its own specific expertise. Buff Hort works with the built environment; Buffalo Horticulture deals with commerce, and studies plants and construction as commodity forms and art in history. My study in horticulture (among other things) is of plants that are in cultivation and available as materials for us to build the landscape with.