Category Archives: Horticulture

Choosing a Tree: Issues of Structure and Growth

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Right Plant Right Place covers a lot. Usually when you hear it used the speaker is referring to matching the plant with the growing conditions: soil, sun, climatic conditions, size, etc. Here, I’m going to address the physical structure and growth of a tree as it relates to place, Carpinus betulus ‘Fastigiata’, in this case, as it is often used as a ‘street tree’. The Upright European Hornbeam has proven its value as a street tree. It is very adaptable to conditions in our region that exist at the curb. That being said there are questions of structure and growth that need to be asked if such a planting is going to be aesthetically successful over the longer term.

Hornbeams across the street from my house after pruning

Hornbeams across the street from my house after pruning

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Desirable Plants, Thugs and Weeds: The Fine Line Between Good and Bad

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Our native Bleeding Heart, Dicentra formosa with Siberian Squill, Scilla siberica…both of these are ‘weedy’ in my garden, the Dicentra spreading quickly from its brittle rhizome while the Squill, an extremely ‘successful’ old fashioned garden plant, persists and increases even in long neglected gardens and homesteads. While neither of these are technically ‘weeds’ they both possess degrees of vigor and adaptability that have allowed them to persist, often in spite of our efforts to limit or eliminate them.

The first in the critically acclaimed ‘Over-Thinking Series’

What is a weed? What differentiates it from any other plant? What about plants like Golden Creeping Jenny? I know those who call it a weed. Is it a matter of generally accepted horticultural opinion? One is on the list and the other isn’t? Is it more than simply a plant we did not plant? We all have those fortuitous seedling volunteers that appear bringing with them a little garden magic. Some of these prove themselves to be quite remarkable and, if found by the right person, if they retain their desirable characteristics when propagated and are stable over time, may become the next rage among the garden fashionistas. They aren’t weeds are they? While not planned for we may choose to welcome certain such plants. To just define weeds as plants out of place, is to render the word almost useless as an aid to understanding our problem.

There is no conspiracy going on in the garden. No malignant intelligence plots and schemes to upset our plans. Not every seed germinates. Not every bit of rhizome or tuber will take over the garden/world without our intervention. Weeds are plants and within the limits of their own genetics they either grow or die. If a seed of Calypso bulbosa finds itself on the ground in the desert. It will not germinate. Eventually it will lose its viability. No one will notice its absence because it never belonged there. All plants possess a degree of vigor. All plants have within themselves a range of conditions they can grow and prosper in. Weeds, are plants that possess the vigor and adaptability to be successful under the range of conditions that we as humans typically occupy. Because we occupy these places, disturb them, because we move about and conduct trade with those elsewhere, we have ‘weeds’. These are merely the plants that do well in the places that we habitually have created. What we should be talking about instead is the quality of ‘weediness’, that blend of adaptability and vigor, that these plants possess.

(Readers should be aware that there are no pretty pictures to either break up the following text or to graphically ‘hammer the lesson home’. Continue reading →

Butia x Jubaea: A Pinnate Palm for Portland – First Test…for me

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Butia capitata at my front stairs along with a new Beschorneria yuccoides 'Flamingo Glow' and a Agave parryi 'Hauchucense'

Butia capitata at my front stairs with a new Beschorneria yuccoides ‘Flamingo Glow’ (I had just removed a Beschornieria septentrionalis, divided and potted the starts up. The replacement has more flamboyant foliage.) Iris douglasiana ‘Canyon Snow’, various low Sedum, Asarina procumbens, x Halmiocistus ‘Merrist Wood Cream’ and an Agave parryi ‘Hauchuca Blue’

My friend Steve has urged me to periodically write about my experiences in the Denial  Zone…so here’s a little something:  We all know you can only go so far with the whole tropical thing in Portland if you’re not going to invest in a greenhouse.  Those of us who try to mimic the tropical look realize that we have to seek out the temperate and a few sub-tropicals that give us that ‘feel’.  Bold foliages are key.  Architectural plants, and just as important strong foliage contrast.  This is not the place for subtlety.  Strappy, fuzzy, split and dissected, compound pinnate and palmate, glossy, drip tipped, bold variegation and wild patterns…over the years observant nurseryman and plant hunters have brought us a smorgasbord of unusually foliaged plants.  Plant breeders have pushed the limits crossing hardy species in ways that mimic their tropical cousins, I’m thinking Hibiscus here.  But still there are certain plants, certain forms and silhouettes, that are hard to replace.

Palms are one of these.  Many of us grow various palmate forms like genus Trachycarpus, T. fortunei, most commonly, while others have used T. wagnerianus, T. takil and T. princeps.  There are many others but of unproven hardiness.  Another form of Palm are those with costapalmate fronds, of these I have a Sabal minor doing fine at home slowly getting bigger in the ground for the last four years, (It’s more than ten years old.  I’m of the age now where I just say something is ten years old because it’s easier than checking.  It may actually be 12-15.) and a Sabal x ‘Birmingham’ I have high hopes for probably destined for a few more years in the pot before I try it out in the ground.  (The genus Sabal includes the Palmetto Palm native to the coastal southeastern US. They tend to be slower growing than Trachys, preferring more heat, often with larger more deeply segmented fronds. For those of you who don’t know, costapalmate are intermediate between palmate and pinnate.  The stem extends into the frond where the segments separate and fan out.  This extension may be slight as it is in Sabal minor. Instead of having the segments radiating evenly from one point at the base, the ‘base’ is slightly elongated stretching it as if it were briefly considering being pinnate.  A casual look might leave the observer thinking that something is slightly off with what appears to be a palmate leaf.) Perhaps others will be found growing in the extremes of their home ranges that can take zn7 and 8 consistently with smiles.  I planted the aforementioned Trachys over the last several years in and near Waterfront Park’s bowl.  (Actually, the T. princeps is new this spring.  Cross your fingers.) They are consistent and durable performers…even through last winter.

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Tools of the Trade: Pruning Shears, Loppers and Saws

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(This is a slightly edited version of the same article published a few years ago in the HPSO Bulletin.)

The Pruning Series, 1

If you garden you will need to prune. Pruning is necessary not only for garden aesthetics but for the health and survival of plants in your garden. Gardens are our own inventions. They are infused with our intentions while the natural forces at play in any landscape work toward their own conclusion. We gather plants from disparate places around the world, put them together on soils in climates they did not evolve with, in intimate relationships we impose. We will have to be involved in an ‘editing’ process that is ongoing within the ebb and flow of plant growth and death that will include shuffling, removals, additions and pruning. Gardens are dynamic. Whether we make ‘good’ plant choices or not our continued involvement is a given. If we are good observers and modify our actions accordingly, we can move our gardens toward a balance that will require less of us. If we have aesthetic priorities that we are unwilling to relinquish, we will have to work to assure they continue. If our knowledge of how the plant will perform on our site is less than perfect and we fail to take all of it into consideration when we planted, we will have to intervene, maybe regularly.

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Landscape and Culture: Redefining the Urban Landscape – Single Use Corridors – Railroads

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R x R below Division St. and 9th

R x R below Division St. and 7th

Landscape, is a human concept. It is more than simply a place, or the land that we occupy. Land becomes landscape when it passes through the lens of our eyes and we ascribe to it not only our own values and emotions, but also the value and emotions of the culture we share as members of this society. Just as we are shaped by the laws and culture of our society so to is the landscape. Without, sometimes, considerable conscious effort we cannot see the landscape free of this ‘cultural looking-glass’. As individuals I don’t think it’s ever possible to look at the landscape neutrally, though over time, our experiences can change us, and so, also, how we value and view the landscape. This is important if we ever want to change our relationship with the landscape we live in, if our role as an actor in the landscape is to change, if we are to, individually and collectively, become responsible stewards of the places within which we live…because it is one thing to say we are good stewards and something else entirely to actually be one.

People continue to be drawn here to the landscape of the Pacific Northwest. We all have our favorite places that hold us, and, unfortunately, over time, can come to sadden us as we see them degraded and homogenized by the momentum of our culture, the economic engine we all depend on, that is still systematically converting our landscape into one that can be found almost anywhere with the exception sometimes of a geography too expensive to alter. Even climate, we are beginning to realize, is within our ability to change, though we are finding, such changes are likely beyond our control. Continue reading →

Photosynthesis Types: C3, C4 and CAM a simple overview

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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: http://www.marietta.edu/~biol/biomes/photosynthesis.htm

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

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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 →

Katsuras as Street Trees: picking the right tree

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photo 1

Sometimes it pains me to take walks.  I was on my way home from the Imperial Bottle Shop and Tap Room, walking down SE 26th south of Powell Blvd when I came across these four Katsura trees planted in a 4′ wide parking strip, no curb parking with a painted bike lane right next to the curb.  Katsura trees 24″ from the bike lane.  How is that going to work?  Trees grow.  Branches extend and caliper up.  Branches hit bicyclists and pedestrians in the face and people crash and or break branches. (Yes, I know these can be limbed up over time but we all know how often that doesn’t happen and what are these trees going to look like if all of the branches are cut off of the street side up to 14′ for traffic clearance.  Trucks regularly use this street.)  And then there’s the whole it’s just the wrong plant for the growing conditions thing.  Katsuras grow in the mixed woodlands of Japan with moderate temps and summer rainfall.  So that looks like 3 strikes out of 4 pitches.  Landscape architects still love these…so do I, but planting them in positions with reflected heat with limited root runs through compacted mineral soils!!!! It’s 90 degrees today, their foliage is stressed even with their water bags filled around their bases.  I have seen many more bad examples of Katsura use over the last 25 years than i’ve seen appropriate.  If you’re going to plant them plant them in a woodland or along the edge where they will be protected from intense direct  sun and make sure they have a long cool root run.  This is so wrong.  Now we’ll all have to watch these limp along getting by stressing until they die or become so damaged someone removes them. Continue reading →

Drought Tolerant Plantings: A Review of Riverplace and South Waterfront, Summer ‘12 (updated Aug. ’14)

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Riverplace Esplanade Bank looking south along the Marina toward the Marquam Bridge

Riverplace Esplanade Bank looking south along the Marina toward the Marquam Bridge.  My last big xeriscape experiment.

The following is an evaluation I initially did while still working for Portland Parks and Recreation.  I’ve edited it a bit and added a few things to make it more current.  I think it’s important for people to know what others are doing, what they’ve tried and what were the successes and failures.  While kind of long it is still a brief look at the conditions on a few sites that were under my care and my observations concerning their performance.  As Downtown area Parks these landscapes are very accessible for those curious to see how these plants have done on the ground.  Now, most of you if your gardening is limited to your own backyards will never have to deal with landscapes so large, nor will your growing conditions, specifically your soil, be the same, I thought that it would be interesting to share this anyway, in addition to letting you know where you can come see how these plants can look in a landscape.  All were planted small as they tend to better adapt to their sites when small, but some are beginning to mature and show what they can do.  Anyway, I view our Parks as a public asset.  There are many valuable and important plantings around us, that the public is largely unaware of.  Part of my role here is to change this situation through promotions like this and by continuing to work with horticulturist to create some kind of database of public and private plantings that is accessible for viewing by the general public. Continue reading →

Erythrina x bidwillii: Coral Bean Shrub

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Erythrina x bidwillii from Piece of Eden

Erythrina x bidwillii from Piece of Eden

Every gardener makes decisions about which plants to buy, which to increase, limit or get rid of. It’s part of gardening. We each have our biases that cause us to tolerate plant ‘behavior’ that an otherwise ‘rational’ person would never choose. A ‘rational’ gardener would not knowingly acquire plants they knew to be tender in their zone nor would they collect plants with growing requirements they cannot provide. Who said gardeners were rational?  Much of our lives as gardeners we spend learning just these things about ourselves and our little plats of earth. Most gardeners are hopeless optimists and find themselves constantly tempering their runaway excitement for a never ending parade of plants, after all we have limited budgets for replacements and only so much energy to deal with too much attrition. Besides, all of that plant death can get kind of depressing.

The reality is that we each draw this line differently. Continue reading →