Our brightly colored world

By Dr. John Palka (from his blog site)

We are now headed into the dark part of the year. The winter solstice is less than a month away. For the moment, however, let us think not about these short days and long nights, but back to the summer—and especially to summer’s brilliant flowers. How do all these colors come to be? What allows us to perceive them? Why don’t we see the world in the black-and-white of old-style photographs?

Let’s start our exploration of these questions in the northwestern corner of Washington’s Puget Sound, a stone’s throw from the Canadian border. Here lie the San Juan Islands, hundreds of islands, islets, and projecting rocks so beautiful that people sometimes ride the ferry just to glimpse them from the deck, never even getting off to walk on land. These complex and convoluted landforms are home to thousands of birds and marine mammals, their shores are decorated with exotic-looking creatures bumping up on one another, and every bit of soil is covered with rich vegetation—stands of Douglas fir and cedar, a bright coastal fringe of madrones with their vivid red-orange bark and brilliant white blossoms, and grasses that turn golden with the advance of summer. In the spring the islands are carpeted with wildflowers, and none more richly than eleven-acre Yellow Island.

Yellow Island has been owned and protected by The Nature Conservancy since 1979. Its flora is basically intact, the way it once was on all the islands, and in the spring it is brilliant.

Buttercups
The masses of yellow that give the island its name are buttercups.

The photographer finds it hard to move forward, there are so many sights to delight the eye and invite a picture. The biologist is thrilled that such a place still exists, so close to the densely settled metropolis of Seattle and its surrounding cities. And I, in addition to these feelings, find myself marveling at the colors themselves.

Camas
The purplish-blue camas lily, prized by Native Americans for its edible bulbs, abounds.
Paintbrush
As does the brilliant red Indian paintbrush.

All the Colors of the Rainbow

The plants on Yellow Island glow with literally all the colors of the rainbow, from blue, through green and yellow, and on to orange and red. They call out a question that scientists and philosophers have asked literally for centuries—how do leaves and flowers come to have the colors they do? Indeed, why are objects of any kind seen by us as having distinguishable colors?

The sensation of color is an everyday aspect of conscious experience for most of us, but what makes it so? It needn’t be, for we are all familiar with a world without color, as portrayed in the marvelously evocative black-and-white prints of master photographers. It is also different for those who have some form of colorblindness.

For us to experience a colored world requires the operation of many mechanisms, not all of which are understood by today’s science. The foundation of the entire complex chain of processes leading to conscious experience is, however, the interaction of light with molecules. Inasmuch as there are two partners in this interaction—light, and the molecules that are affected by light—we will need to consider both of them.

Let’s start with light, particularly sunlight, the natural light in whose presence all life on Earth evolved. Thermonuclear reactions occurring within the Sun emit massive amounts of energy that streams out in all directions, through the solar system and beyond. The total quantity of solar energy reaching the Earth is just right to warm the planet to a temperature that has enabled the evolution of life. It arrives on Earth’s surface in the form of a vast range of wavelengths of electromagnetic energy, from the extremely short-wavelength and highly energetic gamma rays and X-rays at one extreme, to the long- wavelength, low energy radio waves at the other. Between these two ends of the total electromagnetic spectrum the ratio of wavelengths (and hence also of energies) is 1018, or 1 followed by 18 zeros. Gamma rays are of atomic dimensions, so short that we have no sensory experience to compare them to, while radio waves are measured in miles. Nevertheless, their basic nature is the same. Extraordinary!

Visible light is a tiny, tiny slice of wavelengths in the middle of this vast range, with ultraviolet (sunburn!) just to the shorter wavelength side, and infrared (heat!) to the longer wavelength side. The spectrum that underlies our experience of light and of the visible world runs from violet to red. Here is what this spectrum looks like on the ceiling of a friend’s apartment, with the colors separated by a faceted glass ball she has hanging in her west-facing window.

spectrumAnd here is the same spectrum seen in a rainbow over the rolling plains of Montana, north of Yellowstone National Park.

rainbow
Rainbows and Flowers

The sunlight that reaches our Earth literally consists of all the colors of the rainbow. But what about the flowers? How do we relate the colors contained within the apparently colorless light that is shining on a meadow to the colors we experience as being the property of the buttercups, the camas, and the paintbrushes?

To come to a deeper understanding, think about a colored liquid that you can handle easily yourself, say red food coloring. You grasp the tiny bottle, squeeze a few drops into a small glass of water, and voilà, you have red water. White light shining in from one side of the glass emerges as red light from the other side. Test it. If you let light shine through the glass and onto a sheet of white paper, you will see a patch of red.

What happened to turn the white light that entered the glass into the red light that exited? When light struck the dye molecules that were dissolved in otherwise colorless water, some wavelengths of light were selectively absorbed. If they were absorbed, they could no longer pass through the solution and be seen on the other side. The color of the light exiting from the solution, therefore, is due to the wavelengths that were not absorbed.

This is a bedrock principle that underlies our experience of color, and that we will explore in several subsequent posts. Molecules absorb some wavelengths of light and fail to absorb others, and the wavelengths that are not absorbed are ones that can reach our eyes and be seen. Notice that there are two partners dancing to manifest this principle, the light and the molecules absorbing the light. This partner dance will be our foundation as we explore the amazing realm of color. For now, just go out into the world and pay attention to the colors you see, being grateful for the privilege.

Watch a silly product morph into a lawsuit

A few years ago someone emailed me information on another garden miracle – this time a product called Mighty Wash. I found my notes on this product as I wondered what I should post about today. The sales information at the time advertised Mighty Wash as “frequency water” (which we’ll get to in a minute). Here’s part of the original advertisement:

Mostly water - plus "pink sauce" according to lawsuit documents
Mostly water – plus “pink sauce” according to lawsuit documents

“Mighty Wash is a new revolutionary way to solve your spider mite problem in all stages of development from eggs to adults…Mighty Wash is a ready to use “Frequency Imprinted” foliar spray. It is imprinted with special frequencies which target fleshy bodied insects. The use of frequency is nothing new to our world, and as you probably know all things have a frequency. What makes our products special is the fact that our proprietary frequencies are holding and stable for at least 2 years and running.

“One attribute of our Mighty wash is that it paralyzes the insect on contact not allowing it to flood out eggs and begin the resistance process! Essentially there is no resilience that can be gained from or product unlike so many others, and without the use of any chemicals. Mighty Wash does have very low levels of our naturally derived botanical oils, along with frequency make it the cleanest solution to your spider mite problem.”

Mites "flooding out eggs" [Photo source Wikipedia}
Mites “flooding out eggs” [Photo source Wikipedia]
When I looked for the manufacturer’s current information (an LLC called NPK), I couldn’t find reference to “frequency water” and its miraculous properties. After a bit of internet digging, I discovered that Mighty Wash was the subject of a bitter trademark dispute.  For me, the best thing about this dispute is the deposition, which states exactly what the original makers of Mighty Wash claim their products do:

“Yeti invented and manufactures three plant washes using a confidential and proprietary formula and process that includes electronic frequency imprinting.”

They accused the defendant of making knock off products “not manufactured using Yeti’s proprietary formula and process” resulting in products “substantially less effective than Yeti’s Products.”

Leaving the legal battle for a minute, let’s see try to figure out how this product is manufactured. “Frequency Water” is water that’s been exposed to vibrational energy or to minute quantities of dissolved substances. That’s the “electronic frequency imprinting” which is referred to in the legal complaint; it’s also called “water memory” and is the foundation for explaining how homeopathic dilutions work.

Homeopathic medications are diluted until nothing is left except water [[Photo from Wikipedia]
Homeopathic medications are diluted until nothing is left except water and presumably the memory of the substance [Photo source Wikipedia]
It will come as no surprise to readers of this blog that there’s no reliable, published science behind any of this. What is surprising is the amount of money these companies make on selling water in a spray bottle. Mighty Wash and related washes (PM Wash, Power Wash, and Ultimate Wash [which is “Mighty Wash without food coloring”]) must generate healthy sales for two companies to squabble over the trademark of a product that is basically…water.

And the Irony Prize goes to the charges of fraud and false advertising leveled at NPK by Yeti Enterprises.

Academic freedom vs. science-based advice

Those of you that have followed The Garden Professors for some time know that Jeff Gillman and I are relentless in our pursuit of gardening myths to explode. Social media – Facebook in particular – seems to be a natural breeding ground for dumb and/or dangerous home remedies that go viral. Most of these have no basis in actual science and are easy to dismiss. Other recommendations may have some science behind them, but a careful review of the literature often shows that the bulk of research does not support that particular practice or product. These ones are trickier to deal with, and nothing has been trickier for either me or Jeff than compost tea.

Nurseries often carry compost tea products (this one is now defunct)
Nurseries often carry compost tea products (this one is now defunct)

The two of us have posted extensively on this topic in the last six years: just use the search function over in the left hand column of this blog and type in “compost tea”. You’ll find enough reading to keep you busy for a while. I summarized the state of the literature a few years ago in the now-defunct MasterGardener Magazine and to be honest the accumulated literature hasn’t changed much in terms of generating solid science supporting compost tea use. But its popularity seems to be increasing among landscape professionals and gardeners alike.

Informed Gardener page

I get a lot of questions on compost tea from Master Gardeners in particular, who are bound by their positions as university volunteers to use science-based information. One of their major resources is the state university associated with their program – and recently this has become a problem for WSU Master Gardeners. Because on the Washington State University website you can find one professor who cites the lack of credible, consistent science on compost tea usage and another professor who provides workshops and webinars on making and using compost tea. Master Gardeners are understandably confused about what they can recommend and irritated that their university provides conflicting information. Why, they ask, does the university allow this to happen?

GP page

The answer is found in one of the most important values that universities protect: the academic freedom for faculty to speak their minds. Ideally this means that faculty can speak up about topics that are unpopular with university administrators without fear of reprisal, but it also means faculty have a soapbox on pretty much any topic they wish. And that’s whether or not they have any expertise or credibility on that topic. (For a particularly egregious example, one needs look no farther than prestigious MIT who has a research scientist with no expertise in biology or chemistry but who publishes articles in marginal journals linking glyphosate – the active ingredient in Roundup – to just about every known human malady.) Universities tend not step into this fray as it is a slippery slope – who decides what faculty speech should be censured and which should not?

GP group

How can Master Gardeners and others decide what information to believe? Well, that’s actually the mission of this blog and our Facebook page and group – to provide the best current gardening science and to help the public increase their scientific literacy skills. Science is not immutable – it advances as credible, published evidence accumulates. When and if compost tea ever becomes a consistent, effective product, we will be the first ones to share that information.

Moss magic

In my opinion, no coastal Pacific NW garden is complete without moss softening the edges of a rock garden or nestling between paving stones. Now that the rains have returned, mosses are lush green sponges, absorbing sound as well as water. They are the finishing touches to our native landscapes.

Bloedel Reserve moss garden
Bloedel Reserve moss garden

A few months ago, however, mosses looked quite different. With our particularly hot and droughty summer, mosses were brown, dry and brittle just like our lawns. But unlike those dead blades of grass, the mosses were only in a state of environmental dormancy. All it took to revive them was water.

Here’s a patch of moss in our home landscape during a hot dry spell. It’s dry and brown:

Dormant moss
Dormant moss

Here’s the same patch of moss 20 minutes after I watered it:

It's a garden miracle!
It’s a garden miracle!

How can mosses recover so quickly? Well, mosses are one of the most primitive groups of land plants still in existence. They lack a true vascular system, so their “roots” are only anchoring structures – they don’t absorb water. Instead, water and nutrients are taken up over the leaf surface. As soon as water hits the leaves, it’s absorbed and literally throws the switch to turn everything back on. Leaves expand, chloroplasts start to absorb sunlight, and the photosynthetic machine is humming along.

In fact, my undergraduate major advisor was a bryologist (one who studies mosses). Jack Lyford’s lab was stacked ceiling-high with shoe boxes. Each box contained a different species of moss – completely dried out of course. All he had to do was take out a piece and place it in a dish of water. Within minutes it was fully functional and ready for study.

So make room for some moss in your garden. It’s a tough and fascinating little survivor.

Your new word for the day: thigmomorphogenesis

I just finished reviewing 4 manuscripts for three different journals and boy is my brain fried. My private reactions ranged from “I can’t wait until this one is published!” to “If I were to use sheet mulch this manuscript would be my first choice.” Anyway, it was the latter manuscript that got me to thinking about what can go wrong with experimental design, which brings up today’s word: thigmomorphogenesis.

This is a great word for those who enjoy figuring out word meanings by deciphering the (usually) Greek or Latin roots. (This exercise also helps you figure out how to pronounce it.) We have “thigmo-” which means touch, “-morpho-” which means appearance, and “-genesis” which means beginning. String them all together and you get the phenomenon seen when plants respond to mechanical stimulation by changing their growth pattern and hence the way they look.

Wind direction from the right creates an asymmetric hedge.
Wind direction from the right creates an asymmetric hedge.

You can easily see examples of thigmomorphogenesis in everyday life. Look at a line of hedge plants where the plants on the end are more susceptible to wind movement and brushing by people, animals or vehicles. They are always shorter, aren’t they? Plants subjected to chronic thigmomorphogenic forces are generally shorter than their neighbors and thicker in girth. (For a longer discussion about how thigmorphogenesis works, you can read my online column.)

How does all of this relate to experimental design? Well, think about what happens if you are testing a product that requires applying it to the leaves of plants once a week. Your treatment plants are touched every week. How can you know that any changes in your experimental plants aren’t due to being touched? The way you eliminate this source of variability is by treating all of the plants the same way. When you are applying the product to the treatment leaves, you apply water (or whatever the solvent is for the product in question) to the control leaves. That way thigmomorphogenesis remains just an interesting tongue-twister and not a fatal design flaw in an experiment.

Little ball of horrors

One of the great things about doing a multi-author science blog is that there will be topics about which colleagues will disagree. One of those topics revolves around the best way to prepare woody rooted plants (trees and shrubs) before planting them. This is an area in arboricultural science that is evolving. A search through our blog archives will find many of these posts and for convenience’s sake I’ve linked one from each of us here.

From Jeff (2009)
From Bert (2014)
From Linda (2013)

Rather than belabor the points that Jeff, Bert and I have already made in our posts, I think I can sum up our major difference here: I like to bare-root trees and shrubs completely before planting (so I can correctively prune all flawed roots) while Bert and Jeff prefer a less invasive approach. What we do agree upon, however, is the deplorable condition of the roots of many trees and shrubs that end up in the nursery. Because I do practice bare-rooting trees, I thought I’d use today’s post as a rogue’s gallery of trees that should never have made it to the retail nursery. (All of these trees were ones that I bare-rooted and root-pruned myself before planting – and all are thriving.)

Ginkgo "knee" root
Ginkgo “knee” root
Interlocking redbud roots
Interlocking redbud roots
Junky Japanese maple
Junky Japanese maple
The duct tape around the trunk is where the burlap bag began. While the roots are in pretty good shape, only root-washing could find the root crown of this tree.
The duct tape around the trunk is where the burlap bag began. While the roots are in pretty good shape, root-washing revealed the root crown of this tree (which the “at grade” part of the tree) 10″ below the top of the bag

Another unnecessary tree failure

The end of August brought an unseasonable rain- and windstorm to the Puget Sound region. We had some spectacular tree failures which I missed seeing as I was out of town. But one of our Facebook group members, Grace Hensley, was on the ball and took some great photos of a fallen purple-leafed plum. The first thing you see is the complete lack of a stabilizing root system.

"Rootless" purple leafed plum
“Rootless” purple leafed plum

Now look at the base of the trunk, which is actually a massive circling root that has girdled the trunk over time.

A big wooden donut
A big wooden doughnut

By now you must be able to see the orange twine extending from the base of the tree to the soil. Yes, those are the remains of the balled-and-burlapped clay root ball that was planted many years ago. Commercial landscapers will assure you that tree roots can grow through the burlap and establish. And this is sometimes true, as in this case.

But what doesn’t happen when the whole B&B mass is plopped into the ground is that circling woody roots aren’t discovered and corrected. Over the decades what started as a small circling root grew bigger and bigger, slowly squeezing the trunk and preventing it from developing girth at that point. It’s kind of like a blood pressure cuff being pressurized but never released.

Trunk growth was prevented by the girdling root
Trunk growth was prevented by the girdling root. The broken part here used to be in middle of the wooden doughnut.

In time, the constricted point becomes so unstable that the tree breaks. Look are how small the trunk that’s still in the ground is compared to the trunk of the tree itself. Windstorms are often the final push these failing trees need.

How long before this neighboring tree fails, too?
How long before this neighboring tree fails, too?

Commercial landscapers say it’s too costly to remove the twine and burlap and clay surrounding the roots, not to mention doing any of the corrective root pruning that might be needed. It’s easier to just plant the whole thing and cross your fingers that the tree lives past the warranty date. This is what happens when you consider a tree as just another design element rather than a living organism.

As a homeowner, however, you can insist that your trees are planted correctly (if you have someone else do the work). Or you can do it yourself. The bare-root method (sometimes called root washing) is an emerging science and it requires thoughtfulness, but it’s certainly better than the conventional approach in terms of long term tree health.