Category Archives: Site Analysis

On Ornamental Trees and the Remaking/Unmaking of Place: Revising the City of Redmond’s Tree List, part 2

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How Much to Water?

Recommending trees from climates with significantly wetter growing seasons needs to stop if we are to continue growing our population. Landscapes as designed, and managed, are the single largest user of residential water. Recommending trees which ignore this problem is irresponsible. Lower water use residential landscapes are possible. Local codes and recommendations must, however, reflect this priority.

Additionally, how much to water is a bit of a mystery to all of us and especially so to non-gardeners. How much? How often? Our watering practices should be determined by the local precipitation and the tree’s needs. What is commonly done, however, is that we water for our lawns and that largely determines what our trees receive, unless we have separate drip systems. A tree’s root system doesn’t stay neatly between the lines. They quickly extend out well beyond the span of the tree’s leafy canopy. In many cases even 2-3 times as far, taking up water and nutrients. A roots of a tree, planted in a small bed, adjacent to an irrigated lawn area, will move out into the lawn. A tree isolated in a xeric bed with only a few drip emitters, will quickly demand more than such a meager system affords it and such a tree, if it requires summer moisture, will struggle while competing with its nearby  ground level growing neighbors. Again ‘neighbors’ should share compatible requirements so all can thrive on the same ‘diet’ and moisture regime. Continue reading →

On Ornamental Trees and the Remaking/Unmaking of Place: Revising the City of Redmond’s Tree List, Part 1

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Perhaps an odd tree to start this with, Juniperus scopulorum ‘Woodward’, is not a ‘shade tree’. It is not deciduous. It is a narrow, fastigiate form of Rocky Mtn. Juniper that, growing to a height of 20′ with a 2′-3′ spread can serve as a formal accent in colder climates like ours as a ‘replacement’ for the more tender Italian Cyperss, and it can do quite well here with very little supplemental water.

Trees, specifically ornamental shade trees, have become an expected and desired part of our urban lives, at least util their leaves fall and await our cleanup. Many associate long tree lined streets and avenues with urban living. Broad Maples. Lofty Elms. Plane Trees and, in tighter spaces, perhaps Cherrys, Crabapples and flowering Plums. Urban trees provide several notable ‘environmental services’ increasing our comfort level with their cooling shade, their capacity to remove pollutants from the air, cover and nesting places for birds and the sequestration of carbon. Trees are generally viewed as a public good, necessary even for our lives. We can get quite emotional about them. So it seems a bit ‘wrong’ to suggest that this ‘ideal’ may not always be ‘best’ or even desirable.

Broadleaved deciduous shade trees are ‘naturally’ members of mesic, temperate to cold-temperate regions of the world. That is where they evolved and where when we plant them out, where they do best. When we begin planting them outside of their historic natural ranges, especially when we ignore the conditions, the disparities and the extremes between their natural ranges and those where we choose to plant them, then we can have some serious problems. The trees may struggle along, or if we remain committed to making up for our local area’s lacking, usually in the form of supplying more water, they can do reasonably well. But this suggests possible real problems as one moves further away from the conditions of a tree’s natural limits and increase the numbers planted out. Where is this water coming from and what are the impacts of removing this water from its normal and healthy cycling of which it is a part? What will be going without? And, is that cost worth the losses it creates? Our selection and planting decisions depend on how we value that which is lost! In short, the typical deciduous shade tree of our imaginings does not belong here in a desert. Continue reading →

Weeds: What We Need to Do at DCVS

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Looking NE from the gate at Northwest Way, other than a handful of juvenile Juniper there is literally nothing native of value across this roughly 9 acre spread. The other two undeveloped phases are equally bad, having a similar mix of weeds.

The question I keep hearing is, ‘What do we do?’ Many, if not most people living here now, have expressed frustration and more about the Dry Canyon Village South, DCVS’s, landscapes, specifically the berm, the mini-parks,  the Circle and the 25+ acres of undeveloped, uncared, for property we share space with. They ask me because they know I cared for Park landscapes, as a field horticulturist, for almost 30 years, Parks which often included natural areas of over 100 acres, to little neighborhood parks and intensively developed and used urban parks in the downtown core. I also haven’t been shy about my criticism of the lack of care, or of even a plan, for the neglected property we are saddled with. Anyone who has cared for a landscape can see the problem here. Leaving disturbed and neglected properties on their own is not a plan and can lead only to their further deterioration and continuing, worsening, ‘weed pressure on the adjacent developed landscapes. Continue reading →

Weeds, Weeding and the Health of Our Public and Private Landscapes: an example from the ‘hood

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Every gardener is a weeder. Gardens are created landscapes, often expressions of the individual gardener or, lacking of intent and design sense, those of a chosen designer. We live in our landscapes as active, responsible, creators, participants and stewards. Gardeners are trying to create a particular look or to grow particular plants native to their area, or with ornamental value or food plants to feed themselves and their families. Some of us are simply pursuing what we understand to be a healthy relationship with one’s place, to undo the damage and allow a new healthy and vital landscape to grow. These are landscapes of our choice. Our intention and control results in various volunteers and weeds finding their own place and so follows the need for weeding. 

We watch carefully, monitor the impacts of our work, attempt to understand what result is moving us closer to our goal and which might be indicators of further loss. Landscapes and gardens are incredibly complex systems and anyone who claims to have all of the answers is fooling himself and you. Our landscapes are broken, by us and our predecessors. The Pandora’s Box of weeds and disruption was burst open long ago. The only way ahead is to find a new path.  Weeds are here filling the niches we have collectively made and maintain for them. The more one is surrounded by aggressive, well adapted weeds, the more time we must spend controlling them. While this can be significant, gardeners mostly take the work in stride, a necessity to reach our goal, a goal which may be the simple act itself, of working in concert with our place…open to its teachings. Gardening, is a way of life, a smaller scale version of farming and the management of large ‘natural areas’ with their attendant commitment, rhythms and demands. Continue reading →

Spruce Park, Redmond’s Newest Park and Our Neighbor: a horticultural critique

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Redmond’s Spruce Park looking NNE from the SW corner toward Gray Butte and Smith Rock in the background. The border beds which follow much of the loop path are ‘native’ plantings according to the conceptual plan. It is common to claim that most of the plants are natives in designed natural areas, but native is not synonymous with ‘natural’. Although natives are used here concessions have been made including such plants as Echinacea purpurea ‘Pow Wow Wildberry’ and Rudbeckia ‘Goldsturm’. In a strict sense Ponderosa Pine aren’t native to this immediate locale either, they require more precipitation than we normally get and the Autumn Blaze Maples are a hybrid of two northeastern North American species.

A landscape, in nature, is a whole, functioning system, capable of perpetuating itself, through out the seasons and years, relying entirely on its own conditions and the cycling of energy and resources occurring on and within it. This is also the definition of a modern sustainable landscape. Ideally they require no inputs or energies supplied from offsite aside from the sun, precipitation and the normal cycling onsite of nutrients and water. A human made, contrived landscape, as all of those built by us today are, may be ‘judged’ by how well they function on ‘their own’, by how well they fit this ideal. Labor and outside inputs necessary to maintain a landscape are then indicators of how out of balance, how far from ‘ideal’ nature and genuine sustainability, a landscape is. A contrived landscape, which ignores the relationships integral to a healthy landscape community ‘demands’ more and more maintenance and support. Given its design and use, a landscape which ignores its site and relationship requirements will deteriorate from the intended design, losing to death component plants while gaining, increasingly, more unwanted available weed species. Design, conditions and use are essential to determine, in this sense, what a ‘good’ landscape is. Continue reading →

Why Bad Things Happen to Good Plants?: On Root Problems, Root Washing, Nursery Practices and Customers

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“To be, or not to be? That is the question—Whether ’tis nobler in the mind to suffer The slings and arrows of outrageous fortune, Or to take arms against a sea of troubles, And, by opposing, end them?”  Hamlet.

Is the question we face as gardeners as simple as, To ‘root wash’ or not to ‘root wash’, before planting?  To some today it has become ‘heretical’ to suggest that it might not be just a necessary corrective, but an unmitigated good…and not doing so dooms a plant to failure.  The practice of ‘root washing’ in its present form, is relatively new to gardeners.  Horticulture, which is a system of techniques, traditions and science, that goes back to our own species’ first intentional involvement growing and selecting plants, has not always included it.  Practices develop over wide spans of time.  Many are retained, others pass away. Root washing has been around as a method to assess damage to root systems, to ease and make more efficient division, to study root growth or cleanse them of particular infestations.  ‘Bare-rooting’, during a plant’s winter dormancy in temperate regions, has historically been done in the field when harvesting or transplanting many deciduous trees and woody plants for shipping and ease of transport.  In some circles today root washing has become an almost literal flash point, pitting proponent against opponent, ‘science’ against ‘tradition’…yet another fracture line to divide society. The road of the absolutist, as with many other human practices, tends to create conflict as evidence of correctness is lobbed back and forth.  My own view is that, like so many other things today, the subject is somewhat ‘grayer’. Science can be on both ‘sides’, or neither, and reality is rarely so simplistic. Continue reading →

Agapanthus for the Maritime Pacific Northwest: Not all of these are well suited for us…or are they?

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Agapanthus ‘Hinag’ syn. ‘Summer Gold’ a Japanese selection brought to the US by Barry Yinger.
Agapanthus ‘Peter Pan’
Agapanthus ‘Storm Cloud’
Agapanthus ‘Tinker Bell’

A fellow gardener asked the question about whether there were a list of sure thing Agapanthus, plants that a beginner could confidently choose and have success with in most of the maritime PNW.  I’m going to say no.  All of these are South African natives and while many of us can grow these in our gardens, because our conditions overall are marginal, a gardener is going to have to possess a good understanding of their site in particular and some knowledge of the cultivars that they are choosing.  I’m going to borrow here from Manning and Goldblatt’s book, “The Color Encyclopedia of Cape Bulbs”, which discusses the bulbs of the Cape Floristic region and those adjacent areas spilling over into other parts of South Africa. Agapanthus species are native there, endemic in fact, occurring naturally no where else in the world.  I’m also relying here on the SANBI website, the South African Natural Biodiversity Institute which has put together an incredible national program, which all countries should be building for their own countries.  Being a South African plant aficionado I visit it frequently. To this I add my own observations and speculations, having grown several Agapanthus over the last 25+ years in Portland: These come from warm temperate and subtropical areas in South Africa, 10 species total, 3 limited to the Cape itself, all of which tend to occur in rocky grasslands.  Other botanists have downgraded 3 of Manning and Goldblatt’s species and given them subspecies status recognizing only 7 species. Continue reading →

Agave colorata and its Blooming Attempt in ’18

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Agave colorata before flowering initiation, growing nearly horizontal, with a broadly cupped lower leaf holding water. From the Irish’s book, “Agaves, Yuccas and Related Plants”, “The leaves are 5-7″ wide and 10″-23” long [mine were all at the small end of this range] They are ovate ending in a sharp tip….The leaves are a glaucous blue-gray and quite rough to the touch. The margin is fanciful with strong undulations and large prominent teats of various sizes and shapes. A very strong bud imprint marks the leaves, which usually are crossbanded, often with a pink cast [not mine], and end in a brown spine 1-2 in. long.

This is one of the first Agaves I ever grew. Pictures on line of its rosette first caught my
interest, their leaf color, substance and sculptural qualities, the margins of its broad, thick leaves, with their rhythmic rounded ripples, each tipped with a prominent ‘teat’ and spine. This is not a large plant, typically growing 23″- 47″ in diameter and my plan was always to keep it in a pot as it is from coastal areas of the Mexican state of Sonora, found sporadically in a narrow ‘band’ south into Sinaloa.  Agave colorata is very rare and uncommon in nature and growing on steep slopes of the volcanic mountains in the coastal region in Sinaloan thornscrub. It often emerges from apparently solid rock cliffs sometimes clinging high above the water below.

Growing in Sonora and at Home

It is poorly adapted to our wet winter conditions though it is reputedly hardy into USDA zn 8, or as low as 10ºF.  Its natural northern limit is thought not due to cold, but by excessive aridity in the northern parts of Sonora.  I didn’t test it, leaving it outside under the porch roof, bringing it in when forecasts called for below 20ºF, as any plant is more susceptible to cold with its root zone subject to freezing. With perfect drainage and overhead protection, you might be able to get away with this in the ground, but the combination of significant wet with our cold is likely too much…still if someone wanted to try….At best I suspect this one would still suffer from fungal leaf diseases, disfiguring the foliage.

This is usually solitary, but it can be found occasionally in small clumps/colonies up to nearly 10′ across, pushing up against each other on their slowly growing and short ‘trunks’ to 4′ high.  My plant produced just a few pups over the first third of its life.

Fig4-5-color

I wanted to include a climate map of Mexico. This one utilizes the classic Koppen system designating the various climates based on temperature and precipitation and their seasonal patterns. Here it has been modified by Mexican climatologists to better reflect Mexico’s complicated geography…even so, because of the abrupt changes in elevation, and land forms, different climatic conditions can occur in close proximity to one another. Mountains can create wetter and drier areas that on a map of this scale are lost.

Sonora has three distinct geographic areas all running along a ‘line’ from the northwest toward the southeast, the Gulf of California and its associated coastal landscape paralleling the Sierra Madre Occidental, sandwiching plains and rolling hills in the middle.  The coast and plains/rolling hills are arid to semi-arid, desert and grasslands, while only the higher elevation of the easterly mountains receive enough rain to support more diverse and woody plant communities, scrub and Pine-Oak forests.

This map comes from the Arizona Sonoran Desert Museum. The link takes you to one of their pages which discusses the natural history of the desert, thornscrub and tropical deciduous forest of Sonora.

This region also varies north to south, the climate drying as you go north into the Sonoran Desert.  Moving south on down into Sinaloa, and further, is the some what wetter ‘dry deciduous forest’ biome with an array of woody leugumes, including several Acacia.  Agave colorata resides in the transition zone in between, in the portion of  ‘thornscrub’ near the Sonoran/Sinaloan border.  North and south the Thornscrub itself changes in composition.  The Sinaloan Thornscrub serves as a transition zone between the desert and the slightly wetter, taller growing, Tropical Deciduous Forest that continues the south.  All along this band running north on into Arizona’s Sonoran Desert are various columnar cactus a food source for Mexico’s migrating nectarivorous bat species.  It is a unique flora community, containing species from bordering floral regions and other species unique or endemic to this transition zone itself.  The area continues to be under threat, primarily by cattle ranching that moved into the region in the ’70’s and ’90’s bringing with it clearing and the introduction of non-native and invasive Bufflegrass, Pennisetum ciliare, also known under its syn. Cenchrus ciliaris, for pasture.  Bufflegrass is also a serious problem north into Arizona.  In Sonora many of the cleared woody species have since begun moving back in, while the smaller, more sensitive species have not.  Climate change promises to further squeeze it. (The World Wildlife Fund maintains a website with good descriptions of many eco-regions I sometimes find it very helpful when trying to understand the conditions of a plant I’m less familiar with.)

When growing plants like this, one should keep in mind the concept of heat zones.  The American Horticultural Society has created a map of the US delineating its ‘heat zones’.  It is based on the average number of days an area experiences temperatures over 86ºF.  At that temperature most plants begin to shut down their metabolic processes…they slow their growth.  Check out the AHS map (AHS US Heat Zones pdf.) and keep in mind that we are warming up!  The AHS map has us, Portland, OR, in zone 4, meaning we experience 14-30 days with highs over 86ºF each year.  Last summer, ’18, we actually had a record 31 days over 90ºF!  Now consider that the coastal/plains region of Sonora likely experiences between 180-210 such days!  Agave colorata may not need this, but it is certainly adapted to such a level of heat stress.  Something to think about, especially when you consider that we receive the bulk of our rain over the winter when our daily highs and lows average for Nov. 40º-53º, Dec. 35º-46º, Jan. 36º-47º, Feb. 36º-51º and Mar. 40º-57º…keeping in mind that we could freeze on most any of those dates.  The Sonoran Desert receives its minimal rainfall in a summer/monsoonal pattern….This is why bringing such ‘low desert’ plants to the Pacific Northwest can add another degree or two of difficulty to your success!

Aug. 26, 2018 I could have taken a similar picture anytime over the last several years. The stem is completely prostrate. You can see dried leaf bases lost over the years. A different angle would have shown additional rooting along part of its length.
Aug. 10, 2018 This shows the center of gravity problem! Growing in the ground, such as the plants at Boyce-Thompson the crowns were supported by the ground and had a less pronounced ‘lean’. The desiccating leaves, especially the lower ones, is already well advanced here, to me indicating a lack of reserves having lost so many leaves over the years from which to draw, especially given that there is not any prominent ‘heart’ tissue.
Aug 23, 2018 looking a bit spindly as it leans back toward the pots center. The peduncle has much more widely spaced bracts.
Aug 26, 2018 the shriveling, desiccating leaves.
Aug 28, 2018 Here, along the upper half of the peduncle the bracts are separating as the secondary peduncles and buds emerge and develop.
Aug 30, 2018 The secondary peduncle nearly fully extended out with tertiary branching spreading the clusters of flower buds held in a crowded groups in umbels.
Sept 3, 2018 Where the secondary peduncles, branches, form the main peduncle, stem ‘zags’ slightly away giving it an alternating, spiraling form. Here you can see the base-up process of development as branching lengthens and buds mature.
Oct 27, 2018 The entire process has been slowing down, the flowers in the lowest ‘branch’ opening on Oct. 12. Here you can see my neighbor’s bees busy working the flowers, some of the long canoe shaped anthers split open and dehiscing their pollen. The overall structure of the inflorescence and the anthers provide the main visual ‘show’ when these bloom the corolla, or petal structure and perianth is secondary.

 

Growing this in a pot made perfect sense to me, but every decision carries consequences, not all of which I anticipated. Most Agave don’t form a ‘trunk’ growing its leaves, in a tight spiral, crowded along a very abbreviated stem, which adds little to its length to separate each consecutive leaf., but Agave colorata adds a little ‘extra’ slightly separating its leaves, resulting in a weak and kind of puny stem. If you’ve ever shuffled pots containing Agave more than a few years old, you understand that their crown, their substantial top growth, is relatively heavy, A. colorata is no exception, in fact their leaves each seem more substantial than leaves on many other similarly sized Agave. This results in a plant that as it grows begins to lean over, eventually, laying flat across the ground. As a Monocot the stems of Agave don’t caliper up over the years as does wood. These have no cambial meristem which would add secondary growth, and diameter, to the stem and as I said, with its relatively massive and heavy crown, it leans.  This is the same characteristic that gives their small colonies their height.

 

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Puya: Growing These Well Armed South Americans in the Pacific Northwest

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[I wrote this originally about 2 years ago as part of what turned out to be a too long look into the Bromeliad Family.  Here I present only the genus Puya spp. in an edited form with the addition of the species Puya berteroniana.  Go to the original article to read about the shared evolution of the several genera and families that comprise the family, why these are not considered succulents and a look at the armed defenses of many plants.  My plan is to breakout at least some of the other genera as well as I think the length of the original post may have put some readers off.]

Puya: one of the Xeric Genera of Terrestrial Bromeliaceae

Puya chiliensis
The inflorescence is very ‘spiky’ in its structure its many ‘arms’ covered with buds.
Each bud will open over time giving a long season of bloom.

The name “Puya” comes from the Mapuche Indian word meaning “point” (The Mapuche people are indigenous to Chile and Argentina.  They constitute approximately 10% (more than 1.000.000 people) of the Chilean population. Half of them live in the south of Chile from the river Bío Bío to Chiloé Island. The other half is found in and around the capital, Santiago and were mostly forced to the city after Pinochet privatized their lands giving them to the wealthy.)…the assignation is clear and the pointed, spiky, nature of this genus is immediately obvious to anyone.  But there is something easy and comfortable about the sound of the word in your mouth when you speak it…poo-‘yah.  Puya are native to the arid portions of the Andes and South American western coastal mountains.  (Oddly, two species are found in dry areas of Costa Rica.)

Puya spp., populate arid western regions of the Andes Mountains up into southern Central America.  These are terrestrial plants, relying on their roots to find the moisture that they need.  They possess the same basic rosette structure common to all members of the Bromeliad family to which they belong, including their petiole-less leaves, which clasp directly to a compact stem structure, funnelling the infrequent, and seasonal, precipitation they get into their crowns and root structures where they can take it up, a strategy very similar to Agave and Aloe which grow under similar conditions. Continue reading →

Winter 0f ’18 -’19: Cloudy, Mild With a Chance of….On Weather, Zones & Plants

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The center green band of these NOAA charts delimits the 20 year average for each day, the bottom marking the average minimum temp and the top marking the average high temp. The red and blue portions of the chart mark the range of temps between that and their record high and low levels. The dark blue ‘bars’ show the actual recorded temps for those days. This chart shows distinctly the initial cold span with the slight warming to well within normal range, followed by a more irregular cooling. The relative steadiness of these temperatures helped plants maintain their slower, more dormant metabolisms for the month. Typically February has been notable for the stability of its daily temperatures, the relative narrowness of the ‘green, normal, band’ indicates this.
This chart for March again shows the slowly warming/rising light green normal band contrasting with the dark blue bars of our actual temps. The March temps appear colder because they shifted the chart downward. The more extreme minimum temperature swings of Nov., Dec., and Jan. have even out, the lt. blue portion narrowing and showing more consistency.

It’s 41ºF at 5:30am on Mar. 12 as I begin to write this.  We appear to have come out of the longest sustained ‘cold’ period of the winter of ’18-’19 which began on February 4 and continued through Mar. 11, a period of 36 days.  Over those days we had freezing minimum temps at PDX, the official NOAA reporting station for the Portland area, on 26 of them.  On two of those days, Feb. 6 and 7, PDX recorded the winter’s lowest temp, 23ºF, making it a zn 9a winter, mild for us historically and especially so for the temperate US as a whole, much of which was experiencing its own much colder temps.  It’s mid-March and our high temps have climbed well above what they were and our forecasts call for milder, more ‘normal’ highs and lows now locally.  It looks likely that not only are we going to be on the ‘warm side’ of normal, but that our lows have shifted into a pattern well out of the freezing range.  (State ODF meteorologist, Pete Parsons, calls for a pattern of slightly warmer and drier weather than normal over March, April and May with the highest chance of this during May.) 

While weather consists of moments, recorded data points, we attempt to make sense of it in its patterns over time…our experience of it.  In this we are much like our plants.  Plants too have their ‘expectations’ of the weather and those conditions that take them outside of them, outside their familiar patterns, the relatively quick changes and perturbations, as well as the longer sustained patterns, and extremes, are ‘noticed’ and make a difference.  How does this winter compare? Continue reading →