“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.

March 1st. We are probably three to four weeks away from Lesser Celandine's emergence. Going back through my photo albums from the past several years, it seems to emerge at the end of March, beginning of April, depending on the weather.

Lesser Celandine is one of the first weeds to emerge that we need to attack. A Spring ephemeral, meaning, the plant emerges in mid March, flowers in April, and is gone, dies back, by early June. I think what happens with Lesser Celandine, what allows it to colonize and take over so much space so quickly in the landscape and garden, is that it emerges before people are actively tending to the garden and landscape. When it does emerge, it's not unsightly, and has attractive foliage and flowers. “Oh. Buttercups!” How can you feel threatened by buttercups? Left alone, the Lesser Celandine goes through a couple seasonal cycles, occupying more and more space, spreading through seed and root bulblets, and then runs clear across and entire garden. You can’t spray it because it is often nested right in close with your precious ornamentals. It gets out of hand quick. 

Control. If its in the lawn, you can probably attack small outbreaks with manual digging. Most likely solution is spot treating with broadleaf weed control. In ornamentals, manual digging. Watch for it in late winter and early spring. Begin attacking it as soon a possible. Always dig it with a weed knife or trowel. Pull roots and soil out as the roots carry little bulblets that contribute to the plants spread. Attack, dig, and disturb every 2-3 weeks, never allowing it to get comfortable. It spreads, quickly! With larger infestations, some say you can limit its force with constant cutting back to the ground with a weed eater. 

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