Category Archives: Horticulture

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

“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

Controlling English Ivy and Clematis vitalba in the Landscape

I wrote the piece that follows while still a horticulturist working for Portland Parks about 20 years ago. It remains largely in its original form with a few additions, corrections and updates.  Both plants are still under addressed in the landscape today.  While employed I maintained my license as a public applicator of pesticides, a job requirement.  I no longer have one, nor do I have a consultant’s license.  In many cases herbicides can be an essential part of an effective strategy for the control of an established population of invasive plants.  Invasive plants, like these, which are listed on your State’s Noxious Weed List,  are there because of the the threat they pose to the environment and their capacity to infect and dominate a landscape, any landscape, across our region.  In more than a few cases manual and mechanical methods of control alone are insufficient to ‘control’ the invasion and sole reliance on them will assure the failure of the establishment of a desirable landscape on a site.  Herbicide use is thus justified.  Large scale restoration projects are often dependent upon it.  On a smaller residential property, with commitment and persistence, a homeowner may be successful, but even then they need to understand that there will be a continuing and significant threat of reinfection from surrounding properties, via birds carrying the fruit of Ivies and wind blown seed from Clematis.  For some species, especially when the scale of the invasion and property are larger, its use may be essential.  For many weeds this herbicide ‘threshold’ is very low before its use is a requirement.  In this way scale works for homeowners as their properties and problems are smaller.  Too often though properties are neglected and then the buyer inherits a serious problem.  Using any herbicide will always have potential adverse effects on the environment, so if you choose to use it make sure you do so effectively. If you choose to use any of my herbicide suggestions, you are on your own.  Do your research, understand your problem, to assure that your actions are effective, safe and responsible.

Getting Down to it: Your Viney Culprit is Probably Hedera hibernica, Irish Ivy, or More Rarely H. colchicum

English Ivy, a friend and co-worker announced early on in a then still continuing series of work meetings concerned with various issues of invasive plants, has been a kind of “anti-poster child” for those working in the regional conservation and restoration field.  Its spread and control has been the subject of innumerable meetings, proposals and actions both fruitful and not.  Eradication is no longer considered a realistic goal by many.  The focus, rather, is on limiting its spread and control.  Like other exotic invaders and introduced guests now run amok, from diseases to various shellfish and weeds, once a particularly well adapted species establishes a viable population base, it becomes a part of the disturbed novel landscape…it’s here and we’re going to have to figure out how to deal with it.  This has always been the way of the world.  The difference today is the rapidity with which these changes have been introduced through trade, the peripatetic travels of man (Man in the generic sense) and our never ending appetite for the consumption and disruption of land.

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

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

Gardening in Public, Charismatic Mega Flora and the Need for a Public Horticultural Intervention

We ‘need’ charismatic mega-flora today, plants that scream out to even the most plant blind of us to take notice, those that create such a sudden and uncontrollable ‘stir’ within us that our simple glimpse of them breaks our momentum, our chains of thought, interrupting whatever we’re doing in that moment bringing about a reflexive interjection, cause us to take notice, create an uncontrollable urge to stop what we’re doing and come back for a closer look!  To tell our parents, partners or friends, to drag them back, for a repeat performance or to see if what we saw is really there or merely a mistake of perception.  And they do come back.  I see them every day, sometimes dragging disinterested friends to see this unimaginable impossibility.  I hear them when I’m out working in the private part of the garden with excited voices, sometimes expletives, “Look at this ‘F@#$ing’ thing! Can you believe it?”  I love this. They’ve come for ‘Monte’!

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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.

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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!

 

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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An Introduction for Gardeners to the Eudicots and the New ‘Phylogeny’ of Angiosperms: Genetics and the APG, Part 1

 

 

While working on a blog posting over the spring of ’17, Palms, Bananas, All Monocots…Oh My! Their Similarities and the Differences that Distinguish Them From Dicots…and why this should matter to you! discussing Monocots, I necessarily said much about Dicots, those vascular, seed producing, Angiosperms (flowering plants) with two cotyledons or ‘seed leaves’.  These were the two major groups of Angiosperms that I grew up with in the gardening world…but, while I was working in my career, this began to change, beginning  some 25 years ago.  I’d been aware of the term Eudicots, or ‘true’ dicots, and knew that all Eudicots also fit within the older category of Dicots, while a small portion of the latter, are left outside.  I was unsure how these differentiated and so, ignorantly (not a bad word), blurred the two together as many have been doing since the concept of Eudicots was first put forward.  The differences between these two for me seemed very ‘arcane’ and fussy, focusing on the tiny pores or furrows, colpi, on pollen grains.  But it is more than just that.  To really understand what is going on in the esoteric world of taxonomy, the naming and organizing of plants and their relationships to one another, you need to look at the genetics, the DNA ‘fingerprints’ of a plant which allows us to follow evolutionary paths back from the plants of today through their ancestors to the earliest forms of life on Earth.  It is about the phylogeny, the ‘history’ and relationships that tie plants together. Continue reading

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

[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

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

On Our Expulsion From the Garden: How Our Ideas of the Garden Shape What We Do

There are those who argue that life is short and violent, that we have nothing to look forward to other than our deaths…so we might as well grab for whatever we can now!….that is the path of the nihilist and the greedy, it serves as an excuse, a rationale for their choices, following an ethic of ‘why the hell not!’  This is consistent with the ‘beliefs’ of those who feel the weak get what they deserve, that anything that opposes their idea of dominance, is weakness and failure and they pursue it with the righteousness of a ‘true believer’.  “Only the strong survive”.  If our gardens can teach us anything it is instead that, ‘He/She who has the graciousness to take only what they need and gives back whatever they are able to, live on through the love and lives of those and that which they’ve nurtured, helped, befriended and mentored along the way and in this way have helped build a richer, more complex and diverse world.’  Our true legacy will be best expressed in the richness and health of the world we leave behind, of those that we’ve loved and taught.  As competitive as the world is, it is this positive, cooperative, supportive aspect of life that makes it all possible.  While the world is divided into heterotrophs and autotrophs, those that must consume to live and those able to grow and metabolize that which they need from the world around them, it requires them both, working in a balance to sustain them all.  We humans, ultimately, cannot be any different if the world is to continue on. Continue reading

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

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

Fabiana imbricata: the Andean Un-Tomato, a Non-Heath That Looks a lot Like its Cousin Cestrum

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Fabiana imbricata has an appearance much like the upright and shrubby Erica arborea…maybe mixed with an upright form of Rosemary…providing a remarkable texture in the garden.

In gardening and botany one of the first things we learn is that not everything looks as we might expect that it should!  Fabiana imbricata, is a member of the Tomato Family, the Solanaceae, yet, if you don’t look too close, it looks like it might belong to the Ericaceae.  At one time I was planning to take advantage of this similarity as I was attempting evoke a South African feel in part of my garden substituting this for one of the many tender South African heaths as the correct Erica species are either too tender, of borderline hardiness for my conditions or are simply difficult to come by.  It was sharing an area in the garden with Restio capensis, Eucomis spp., Melianthus spp. and others to give an impression of South Africa, not a strict species for species duplication of a community.  I didn’t quite pull it off….I’ve done much the same thing when substituting tropical looking temperate plants for the real thing when evoking a tropical feel.  It’s a matter of manipulation…a sleight of the garden hand.

Its Chilean Home and Garden Merit

Fabiana imbricata is not from South Africa, though it shares Gondwanan roots, and is endemic in Chile, occurring very frequently throughout much of its Andean range.  It is in fact identified as a ‘keystone’ species strongly effecting the composition of its local plant communities.  It can be found growing from well into the dry region of Coquimbo in the north, just south of the huge Atacama Desert, south into the wet Aysen region with its many islands and inlets south of the Lake District or Zona Sur.  The vast area stretches along much of Chile’s length which can be driven, on often tortuous mountain roads, for over 1,700 mi., stretching from the arid city La Serena to the small, rainforest town of Tortel, in the south, a distance almost 500 miles further than the drive from Vancouver, BC to Los Angeles, CA….There are not that many plant species in the world that span a similar latitudinal range with its accompanying climate differences.  As you look for this plant moving from north to south through Chile, the soils and its particular niches change along with the temperature and rainfall.  You are more likely to find this growing exposed in rocky scree in wetter regions to the south, while it tends to be more commonly found on sites more protected from the sun’s intensity and into better soils as you move into the arid and hotter north, more protected from the sun’s tropical intensity.  No surprise there, but overall this is an adaptable plant succeeding in cool rainforest to arid, desert like, conditions.  As would be expected across the more arid portion of its range fire is an important factor in maintaining the plant communities balance, riding it of other competing woody plants  and even aiding it in germination, when followed by ample winter/spring rainfall, though this is obviously not essential for its continuing survival in rainforest areas where fire is much less frequent.   This is a very adaptable species and as we live near the Pacific Coast in the northern hemisphere, which mirrors much of the range of conditions, we should be able to have success with it, if we pay attention to its cold limits.  Those away from the Pacific Coast, especially those with ‘continental’ climates or strong influences from them, will have to pay closer attention. Continue reading