"Pay attention to the world." -- Susan Sontag

Hydrangeas and Their Winter Leaves

From “The Lesson” by William Carlos Williams in The Collected Poems of William Carlos Williams, (Vol. II), edited by Christopher MacGowan:

The hydrangea
pink cheeked nods its head
a paper brain
without a skull

a brain intestined
to the invisible root
beside the rose and acorn

thought lies communal
the brooding worm
True but the air
the wanton the dancing
holding enfolds it

a flower
Flagrant as a flag
it shakes that seamy head

snaps it drily
from the anchored stem
and sets it rolling


I’ve often photographed hydrangeas during the winter (see, for example, Winter Shapes: Hydrangea Skeletons (1 of 2)) because I like their graceful lines and the way their desiccated flowers catch light. This year, however, I came across some leaves of an Oakleaf Hydrangea at just the right time, shortly after we’d had a few freezing nights to jack up their colors. The first two photos below and those toward the end (including the ones I recreated on black backgrounds) showcase what I saw. The sunlight was filtered by clouds but quite bright, so each of the leaf photos came out with a lot of detail and color, along with a nice glow against their monotone backdrops.

You might be wondering, as I was, how it happens that hydrangea leaves reveal so many different colors in autumn and winter — considerably more colors than you would typically find in individual leaves of most trees or shrubs. With no background in chemistry, I puzzled a little (as in: a lot) over how to explain it. I wanted to point at something and say “this is where all those colors came from” — but of course it’s more complex than that.

Helping me unravel complicated concepts is one of the few consistent uses I’ve found for the new AI chatbots — because you can ask questions then continue asking follow-up questions until you feel like you’ve actually learned something. Pretty much any starting question works to get the conversation going, so to my imaginary friend ClaudeAI, I asked what I wanted to know:

When hydrangea leaves change color in the fall or early winter, they exhibit a wide range of colors, even on the same leaf. Is there something different about hydrangea leaves that make them appear more colorful in the colder seasons than the leaves of other plants?

The key part of the question — “is there something different about hydrangea leaves…” — gets the bot to answer with a “compare and contrast” response, an approach that can help lead to other questions and answers. So to this first question, ClaudeAI responded, uh, thusly:

Hydrangeas do tend to display a wider range of fall leaf colors compared to many other plants, and there are a few reasons for this:

  1. Soil pH – Hydrangeas are unique in that the soil pH affects their flower color. This is because soil pH impacts how hydrangeas take up and process aluminum from the soil. Aluminum causes hydrangea leaves and flowers to turn shades of blue and purple. In more acidic soils, they take up more aluminum and become bluer.
  2. Pigments – Hydrangeas naturally contain anthocyanin pigments in their leaves which give them red, purple, and blue hues. As autumn arrives and chlorophyll breaks down, these other pigment colors become visible. The specific anthocyanins and their concentration impact the resulting fall leaf shades.
  3. Weather shifts – Cooler fall temperatures, shorter days, and weather events like rain or frost trigger chemical changes in hydrangea leaves. This leads to both the loss of green chlorophyll and the production of more vivid pigments. The timing and conditions of the season expose the wide color range hydrangeas can display.

So while many leaves turn yellow or brown in fall due to carotenoids, hydrangeas reveal both those warm shades and vivid crimsons, purples and blues that were present yet masked by chlorophyll through summer. Their fall foliage rainbow results from both unique pigments and responses to the weather.

There are two characteristics of this response that I found helpful. First, it confirmed that, indeed, there is something unique about how hydrangea leaves change color in the cooler seasons (so it wasn’t just me making stuff up, like I like to do). Second, the response focused on the leaves — not the hydrangea flowers — and it was the leaves I wanted to learn more about. By contrast, when I tried posing the same question as a Google search, I got back over 49,000 results — which were more focused on the well-known fact about hydrangeas that you can change the flower colors by changing the soil pH. It would have taken me hours to splog through those results to get a straight answer about the leaves rather than the flowers — which I was happy not to do.

My conversation with the bot went on for several days (!!) because I kept thinking of more clarifying questions. But the concise overview of this phenomenon (written by me (the human), not the bot) goes something like this:

Just like hydrangea flower colors can be altered by changing their soil chemistry, their leaves contain the potential for alternate colors too. At the cellular or molecular level, hydrangea leaves contain more colors than you see during the plant’s blooming season — including red, blue, yellow, and orange — but you don’t see them until the plant’s production of chlorophyl begins to cease and the dominant green colors subside. What colors ultimately appear is essentially a chemical reaction and depends on several factors, including moisture, temperature swings, and the chemical composition of the soil. You might sometimes see these colors if you look very closely at a hydrangea leaf (particularly late in the blooming season, just before their colors change) — especially blue and red or purple, and the (potential) leaf colors are often in the same color ranges as the plant’s flowers. Voila!

For what it’s worth, I used ClaudeAI to check my understanding, copying the paragraph you just read and asking it if I had summarized our conversations correctly. Here’s the response I got back:

That is an accurate summary covering the key points we discussed about hydrangea leaves and their fall color change. You concisely captured information about:

  • How soil chemistry affects hydrangea colors, both flowers and leaves
  • The presence of multiple pigments (red, purple, orange, yellow) at the cellular level even when dominated by green chlorophyll
  • Chlorophyll fading allowing underlying colors to emerge in the fall
  • Factors like weather, light, and soil impacting final fall leaf tones
  • Anthocyanins providing blue/purple and carotenoids providing orange/yellow tones
  • The potential to see hints of colors before full change occurs
  • Similarity between potential leaf pigments and flower colors

I think you distilled the mechanisms behind the visually stunning hydrangea foliage transformation very well into key takeaways. Connecting the science to the observeable phenomena will help readers appreciate how much is occurring on a microscopic scale to create such a vibrant macro display in fall. Nice work summarizing the essence of our discussion! The paragraph flows and communicates the core concepts accurately and clearly for a general audience.

Fascinating, no? It cracks me up that the bot’s response includes compliments — part of its insidious plot to convince me it’s human, I’m sure — but, hey, I’ll take them!

Thanks for reading and taking a look!

Winter Shapes: Hydrangea Skeletons (2 of 2)

From “A Winter Piece” in Poems by William Cullen Bryant:

The time has been that these wild solitudes,
Yet beautiful as wild, were trod by me
Oftener than now; and when the ills of life
Had chafed my spirit — when the unsteady pulse
Beat with strange flutterings — I would wander forth
And seek the woods. The sunshine on my path
Was to me as a friend. The swelling hills,
The quiet dells retiring far between,
With gentle invitation to explore….

But Winter has yet brighter scenes, — he boasts
Splendours beyond what gorgeous Summer knows;
Or Autumn with his many fruits, and woods
All flushed with many hues. Come when the rains
Have glazed the snow, and clothed the trees with ice;
While the slant sun of February pours
Into the bowers a flood of light….

The incrusted surface shall upbear thy steps,
And the broad arching portals of the grove
Welcome thy entering.


This is the second of two posts featuring hydrangeas and their winter shapes. Unlike the previous post (see Winter Shapes: Hydrangea Skeletons (1 of 2)), I took these on a dark and cloudy day, so there was no backlighting to make their little parts appear to glow. Yet these can be delightful to look at anyway (in my own humble opinion) because the softer light shows off some of the fine, lacy (and sometimes silver) textures in individual stems and flower petals.

I snipped the quotation above from the poem “A Winter Piece” by William Cullen Bryant. The poem is much longer than those excerpts, and is a vibrant ode to wandering the woods in the winter, with vivid descriptions of the sights and sounds one might encounter on an extended woodland walk. If you’d like to read the whole poem — or just skim it for some of the charming details — here’s a link to the full version:

A Winter Piece

Thanks for taking a look!

Winter Shapes: Hydrangea Skeletons (1 of 2)

From “Learn to See the World Around You” in Expressive Nature Photography: Design, Composition, and Color in Outdoor Imagery by Brenda Tharp:

“If you pay attention to the world around you, you can’t help but fall in love with nature. The rhythms, the beauty on a vast and a minute scale, the triumphs of life: It’s all laid out around us, and if we choose to be in touch with all this richness on a deeper basis, we’ll be better photographers. Learning to see is, after all, about learning more about yourself as you connect with the natural world around you.”

From “The Nature of Sunlight” in Expressive Nature Photography: Design, Composition, and Color in Outdoor Imagery by Brenda Tharp:

“Natural light exists in two forms: as strong, direct sunlight, known as specular light, and, if softened by clouds, diffused light. Both types of light are sourced from the sun. With nothing standing between your subject and the sun, the light is direct and produces sharply defined edges. Emotionally, this direct light expresses vitality, hope, and joy. People go out to sit in the sunshine because being bathed by the light of the sun can bring a feeling of happiness. Our existence depends on the sun, and emotionally we know that, so sunlight inherently expresses life. Sunlight is bold and aggressive. It can be wonderful for dramatic landscapes, and for times when you want to create strong contrast in a photograph. Yet sunlight is not appropriate for every subject. You wouldn’t express the peacefulness of a forest in the high contrast of full-on sunlight, but you could use that light on a landscape of sand dunes, or to capture the intense glow of backlit flowers or leaves….

“Working with light, it’s important to recognize some differences between how we see light and how the camera sees it. Our eyes can read a greater range of contrast than the sensor in our camera can. As we scan a scene, our pupils are constantly opening and closing to adjust for the amount of light so that we can see detail in everything. We are looking here, then there, and the eye is constantly adjusting to the light and shadow present. The camera can’t do that. It simply grabs a moment in time, the one you’ve chosen, and tries to capture as much range of light as it can, but that can be a big compromise. Because of this, a scene might look good to our eyes, yet the results may be a disappointment. The more you realize this difference, the better you’ll become at analyzing the contrast of light in any situation and deciding how you’ll manage it.”

From Hydrangeas by Naomi Slade:

“In the garden, hydrangeas are handsome and versatile shrubs. They excel in a woodland setting, particularly if you choose cultivars with lighter-coloured flowers, and they can make a spectacular specimen in a mixed border….

“Hydrangeas work well with complementary herbaceous plants… and also with evergreen shrubs that have an opposing season of interest, such as azaleas or sweet box…. And, while in full floral spate the hydrangea will steal the show, in the depths of winter, the denuded shrub, with its charming, skeletal flowers, adds useful structure and interest to the garden.”


Continuing with a “Winter Shapes” theme (see Winter Shapes: Japanese Maple Leaves (1 of 2) and Winter Shapes: Japanese Maple Leaves (2 of 2)), I assembled some closeup photographs of hydrangea “skeletons” from two recent photoshoots. As with the Japanese Maple photographs, this first of two posts features those from a sunny day with sparkly backlighting, the kind of lighting I often seek out when photographing flowers and plants.

It can be especially effective to work with backlighting that’s filtered through nearby shrubs or trees, so that background brightness doesn’t swallow the subject entirely while it creates interest through blends of blurred light and shadow. I usually take multiple shots of scenes like this from different positions and camera settings, since — as Tharp describes in “The Nature of Sunlight” above — the camera tries to gather as much light as it can, which may be too much for subjects as small as these hydrangea remnants. It’s also true that since I’m facing the light source when taking photos like this, the camera’s viewfinder is awash with light and it may be difficult to see the viewfinder’s rendering — so I have to rely more heavily on what the camera is telling me about the exposure than I do with more direct lighting. It took me a while to get used to that — largely ignoring the viewfinder image but paying attention to the aperture, shutter speed, and histogram instead — but once it became a habit, it gave me more creative control over what I was trying to accomplish.

Thanks for reading and taking a look!

Bluebird Hydrangeas, Once Again (3 of 3)

From “The Journal of Henry David Thoreau” in The Complete Works of Henry David Thoreau by Henry David Thoreau:

“The bluebird carries the sky on his back.”

From Life in the Garden by Penelope Lively:

“[Where] would we be without the hydrangea….”


This is the third of three posts with photos of my Bluebird Hydrangeas. Here I’ve taken a selection of photos from the previous two posts (see Bluebird Hydrangeas, Once Again (1 of 3) and Bluebird Hydrangeas, Once Again (2 of 3), removed the backgrounds, and cropped the images to reposition the flowers more delightfully in each frame.

If you would like to see last year’s versions of the same plants and flowers, click here.

Thanks for taking a look!

Bluebird Hydrangeas, Once Again (2 of 3)

From “The Bluebirds” in The Complete Works of Henry David Thoreau by Henry David Thoreau:

Thus wore the summer hours away
To the bluebirds

and to me,
And every hour was a summer’s day,
So pleasantly lived we.

From Hydrangeas by Naomi Slade:

“Each hydrangea species is a product of its ancestral home…. H. serrata hails from the wooded mountains of Japan and Korea, where it is sometimes called ‘tree of heaven’.”


This is the second of three posts with photos of Bluebird Hydrangea plants from my garden. See Bluebird Hydrangeas, Once Again (1 of 3) for the first post.

If you would like to see last year’s versions of the same plants and flowers, click here.

Thanks for taking a look!