Category Archives: Plant Metabolism & Photosynthesis

This Life: A Memoir, Gambol and Botananomical Tale

Sharpless 249 and the Jellyfish Nebula Image Credit & Copyright: Eric Coles

Sharpless 249 and the Jellyfish Nebula, Image Credit & Copyright: Eric Coles


I hope that you will forgive me this departure into verse, prose, whatever this is…another thread in my life.  I don’t think it is too far amiss, because, after all, horticulture is the ‘art’ and science of growing plants.  Originally I began this as an idea for a children’s story, yes I did, the life of a particular Dandelion, but, probably due to my more recent reading on topics like photosynthesis, cellular metabolism and a biophysics response to the question of, ‘What is life?’…it has morphed…considerably.  When you read this, keep in mind that my intention was to write from the perspective of the Dandelion, a concept pretty incomprehensible to a modern American. 

The Taraxacum Cycle

Stories all begin with a single word, a seed, around which they grow, nurtured over time by the things we all share in common, family, history and experience.  They contain ‘truth’, but are not themselves true, because they must be told in such a way that they lure the reader in and are ‘believable’.  They are organic and grow within us and to the extent that they reflect our own ‘story’, that they meet our expectations, we stay with them and them with us, because there is no story if it is forgotten.  So, the author must manipulate what he knows, he must ‘lie’, to bring you in and keep you, weave truth and lie into a whole.  We take the stories you already know and introduce our own characters, set them in exotic though familiar settings, and, if a writer is good, introduce enough, but not too much, that is ‘new’, different from your cultural experience, your expectation, that you are affected by its unfolding, that you become a part of the story and look at your world in a different way, even if only a little bit.  The word here is Taraxacum. Continue reading

Fiona’s Carrot: Gardening in a Fantastical World


The two Fiona’s of Miss Peregrine’s Peculiar Children, the wilder, organic version of Riggs’ book and the cute Hollywood version of the movie.

[This is a departure from my ‘normal’ posting.  It is an attempt to get to the ‘heart’ of gardening, closer to the spark within us that drives us, the connection we share with the world we live in that has variously drawn us in to the ‘way’ that we have made for ourselves.]

We’re all familiar with the myth of the ‘green thumb’, those individuals magically endowed with the ability to mysteriously grow anything, but as gardeners we see this as the ‘lie’ that it is.  I’ve told people that those of us with a ‘green thumb’ are simply people with the patience and interest to pay closer attention to the natural world and what is happening in it, that we are better observers.  In Ransom Riggs’ fictional world of Miss Peregrine’s Peculiar Children, Peculiars possess powers beyond those of the rest of us, the non-peculiars, normal people.  Some of these might strike us simply as bizarre abnormalities, e.g., an extra mouth on the back of one’s head, the power to command bees some of which live within your stomach??? while others put Peculiars more firmly in the realm of comic book super heroes, such as great strength, invisibility, the ability to create and control fire at will, or its opposite cold and ice…without the tights.  In their world of such possibilities these ‘peculiarities’ elicit fear and, quite often, violence from the normals and worse from those who would take it all for themselves, hence the protective action of the Ymbryne’s.  This is a fantasy story, which places it in a more magical world than stories of science fiction that tend to project our knowledge and capabilities into some future, utopian or dystopian world.  In fantasy worlds the author creates a world and mythology where this is simply true rather than explaining such abilities in scientific terms, and knowing something of magic we accept it at face value.  Such are the abilities of the character Fiona, who is gifted with the ability to powerfully direct the growth of plants, not unlike the character Poison Ivy from the DC world of Batman, though in her case her motivation is to help or protect her friends and others rather than Poison Ivy’s much more self-serving ends. Continue reading

Chilling, Freezing & Surviving: Understanding Hardiness & Preparing Your Plants for Winter


Parrotia persica, Persian Ironwood, has long been among my favorite trees, for its leaf shape, substance, fall color, the overall plant form and for its exfoliating puzzled bark. Hardy to zn4 this plant is tough as nails here requiring no protective effort at all.

[A note to the reader. This is not a scholarly treatment of all of the peer reviewed material on this topic.  There are no footnotes or listed sources.  This is a product of my more than 35 years of horticultural field experience and gardening along with what I’ve gleaned from reading several technical peer reviewed articles on the subject.  Such material is difficult to read and can be off putting and intimidating to even the educated layperson.  This posting is my attempt at interpreting the research and reviews that I read in a way I think is understandable without overwhelming the reader with bi0-chemistry and the technical esoterica scientists must consider in their pursuit of understanding.  Any faults are mine.]

I’ve been thinking about plants and their response to cold having watched the deciduous trees drop their leaves, dug tender plants out of the garden and moved pots around to where they would be adequately protected from freezing temperatures.  We all know what happens to water when it freezes, going from a liquid state to a solid one, its molecules forming crystalline structures, expanded and rigid, responsible for burst water pipes and snowflakes.  Water possesses some amazing qualities, as a solid, kind of counter-intuitively, it becomes less dense floating rather than sinking even taking on some insulative qualities and stopping the convective flow of heat that is normal in liquid water.  At the instant of freezing water releases a small but measurable amount of heat. What happens inside plants when temperatures drop below freezing? How does the plant keep from bursting its own cell walls like the water in pipes within an unheated crawl space or wall cavity of a building?  You’ve seen what happens to plants like Coleus and the sodden black heaps they become upon thawing out. Continue reading

The Subterranean Dance: Plants, Nutrients, Water and Their Relationship in Soil Health

The western coast of North America is home to an amazing array of landscapes each with its particular climate and range of soils.  This is in the California coastal range looking southerly towards the distant Bay area across meadow, native Coast Live Oak, Doug Fir and the Coast Redwood of the Armstrong Grove in the lower creek bottom land.

The western coast of North America is home to an amazing array of landscapes each with its particular climate and range of soils. This is in the California coastal range looking southerly towards the distant Bay area across meadow, native Coast Live Oak, Doug Fir and the Coast Redwood of the Armstrong Grove in the lower creek bottom land.

Third in the Water Series

As I seem to keep repeating, water, makes life possible. Plants and animals, with too little, die. Soil, in a very real sense is alive as well, and requires water to animate it. Without water the teeming organisms that occupy and comprise it, die or lie dormant until they are rehydrated. Topsoil, that thin layer upon which all terrestrial plants rely, is a swarming, largely invisible, community. Its effect on all life are essential and intimate. Topsoil is where all of terrestrial life is grounded. It’s health and vitality reflects that of the life on the surface including our own. As humans we are essentially consumers and, if we are to survive, stewards of the life upon which we depend. Plants are the creators. That is perhaps a bit simplistic because the relationship between plant, animal and earth is considerably more complicated. Life has evolved together, each species, each element, and, because of this, is part of an integrated whole. Continue reading

Following the Vascular Trail: The Path of Water from Soil to Atmosphere

Oak Savanna on a dry hilltop in Shiloh Ranch Regional Park, Sonoma County, California.

Oak Savanna on a dry hilltop in Shiloh Ranch Regional Park, Sonoma County, California.

Second in the Water Series

Try to imagine life without water….No matter how dry it may seem to be here, the soil cracked open in supplication, the lawns toasted and tan, Rhododendrons with their leaves curled and burnt along their margins, Vine and Japanese Maples, their leaves crisped blowing down curbs in late summer’s heat, there is water…everywhere, locked deeply in tissues, bound tightly to soil particles. Like most things, there are no absolutes with water. It is not simply here then gone, but on a continuum of availability. Biological scientists and agronomists will often speak of ‘dry weight’ when looking at growth trying to minimize the variability of water weight in living organisms. They bake the subject in autoclaves reducing water weight to zero without igniting and burning the carbon and more ‘solid’ structure to ash. There is water throughout the structure of plants, hydrating their cells, making possible the many processes at work within them. There is water in the atmosphere even on a blistering hot and clear day in the form of vapor effecting everything from the Evapotranspiration Rate, (ET), to how hot or cold we may feel beyond what the thermometer reads; and there is water in the soil though our plants be wilting or dead of desiccation, and it effectively sucks the moisture from our skin when we work bare handed in it. Water is everywhere even in the dry periods within the desert and, nature is okay with that and has in fact adjusted to it. Our gardens, however, are anomalies we’ve created. We are invested in them and as gardeners we do what we can to assure their survival, and more, their success! Continue reading

On Planting in Drought Conditions: the Relationship of Roots, Water and Soil

I had a novice gardening friend ask me the other day about planting the dry, xeric, part of her yard.  Many of you know how abnormally dry and warm a spring/June it’s been here.  Those of us with gardens requiring routine irrigation started a few weeks ago and we’re expected to be heading into an extended hot/dry period over the next 8 or 9 days with temps over 90 F. (While it is not unusual to experience 80+ deg. days here in June it is unusual when you look at our overall pattern this spring.  Remember that we can also have Junes where it is common not to get out of the 60’s with our famous Portland drizzle day after day while we wait for July and the ‘beginning’ of summer.)  She was anxious to get her new plants in the ground and was asking me about amendments as the soil was baked and hard…. Continue reading

Hiking in Phoenix’s South Mountain Preserve

A Saguaro along the Bajada Trail looking toward the Estrella Mountains in the distance to the west and Ma Ha Tauk Ridge above me to the right.

A Saguaro along the Bajada Trail looking toward the Estrella Mountains in the distance to the west and Ma Ha Tauk Range above me to the right.

(This will be one of several entries describing hikes, botanical gardens and arboretum I visited in southern Arizona this April, 2015.)

Today Julie has work to do (She’s on a buying trip and I tagged along!) so I’m going out, down to the Phoenix South Mountain Preserve to hike a loop on the Bajada (the incline at the base of a mountain formed by the erosion of the mountain) and Alta (or high) trails. The Preserve, at over 16,000 acres is the largest municipal park in the US (Portland’s Forest Park pales at 5,172 acres.) I began my hike going the ‘wrong’ way on the Max Delta Trail having incorrectly read the directions so I added an unnecessary mile by the time I figured it out. The Bajada Trail climbs only 40’ but it constantly wends its way around rocky barriers and down and back up washes filled with tumbled granites…. The hike and region lies within the Sonoran Desert Scrub region, Sonoran, because the majority of the plants are sub-tropical in origin and are associated with the plants of Mexico’s Sierra Madre Occidental and Baja Region, not plants from the Rocky Mountain Plateau. The Salt River, that ‘flows’ south and west through Phoenix, is the northern boundary of this region, where the area becomes transitional as it gains elevation climbing to the Verde River and Mogollon Rim. Okay, too much. Continue reading

Photosynthesis Types: C3, C4 and CAM a simple overview

If you’re curious I found a relatively simple, not too technical, overview on-line titled: 

Photosynthesis – An Overview

There are 3 basic types of photosynthesis:  C3, C4, and CAM.  Each has advantages and disadvantages for plants living in different habitats.

Check it out at:

The bulk of plant species, around 90%, utilize C3, while C4 plants comprise 3% (7,600) of all plant species, but account for 30% of terrestrial carbon fixation.  46% of the Grass Family are C4s, including Corn, Sugar Cane, Millet and Sorgum.  They make up 61% of all C4 plants.  Most C4s are monocots, obviously.  Among the dicots are many species from the Aster, Brassica, Amaranth and Euphorbia families.

C4 plants have a competitive advantage over C3 plants when grown under higher temperature conditions, 30+ C (C4 plants are concentrated in the tropics and sub-tropics where temps are higher), with lower available nitrogen and drought.  With moderate temperatures, available N and water, C3 has the advantage.  CAM have the greatest advantage under desert conditions.

Among other things scientists are trying to engineer Rice, a C3 plant, into a C4 plant, increasing yields and lowering their water requirements for growth.  Rice is the most commonly consumed food plant in the world.

Crassulacean Miracles

Some of my CAM plants: back, Agave colorata, A. americana Medio-Picta; middle, Hechtia 'Texas Red' w/ Sedum 'Anglina', Agave gentryi 'Jaws', Puya venusta, Aloe (?); front, Puya chiliense, Dyckia 'Big Red', Senecio mandraliscae and Agave parryi 'Cream Sickle'

Some of my CAM plants: back, Agave colorata, A. americana Medio-Picta; middle, Hechtia texensis’ Big Red’ w/ Sedum ‘Angelina’, Agave gentryi ‘Jaws’, Puya venusta, Aloe (?); front, Puya chiliensis, Dyckia ‘Red Devil’, Senecio mandraliscae and Agave parryi ‘Cream Spike’

Plants for me are little windows into the working of the world. Beautiful, exotic, grand or seemingly simplistic, perfectly attuned to their place. We are simple animals ourselves our attentions grabbed and later lost by what shimmers and glitters in our minds for a moment. We look, but only partially see. Each plant is an opportunity, maybe a lesson and later forgotten by most of us, unaware that there is anything there to learn beyond our initial attraction to the physical plant itself. The unrolling of a leaf of Liriodendron, like a flag, happening 10 thousand times on one tree, each year across the span of its years, for generations for millions of years. The perfectly memorized pattern of the single enormous leaf of an Amorphophallus as it stretches up out of its corm, fully formed, each leaflet revealed as a piece, entire, not expanding through a growing tip, adding tissue, but revealing itself wholly if we watch. Each plant a miracle to all but the blind.

I was reading an article on UBC’s botany photo of the day site, on Crassula ovata (Jade Plant). It is one of the most common of the Crassula species in South Africa growing on sandy loam soils, with around 12”-18” of rain as part of what some call the ‘Albany Thicket’. Continue reading