Category Archives: Plant Choice

My ‘Droughted’ Weedy Lawn: What do I do With it Now?

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This little stucco house, in the Woodstock neighborhood, is one of Julie’s favorites. It sits on a little rise clothed in an unbroken sea of Juniperus sabina Tamariscifolia (?) punctuated with several Italian Cypress. This landscape has been here for decades and appears to be completely weed free. It’s xeric with enough density to choke out weedy interlopers.  By not adding supplemental water many of our more common weeds are discouraged. Even if you wanted to apply a pre-emergent herbicide I don’t know if it could get to the soil. There is no way for anyone to enter this to remove volunteer Blackberries, Clematis, Canada Thistle or anything else for that matter. Junipers are strongly allelopathic containing chemicals in their shed foliage that build up in the organic layer on the soil surface discouraging successful weed germination.  Many other plants including our West coast Manzanita are allelopathic as well and can be used similarly.  Generally, allelopathic plants require several years to build up an effective layer of weed controlling old leaves to be effective, so our efforts will be necessary for some time.  At minimum don’t remove this layer of old and decaying leaves!  Junipers are also highly competitive in terms of their roots for water and nutrients.  Do I recommend this landscape…not necessarily, as it provides little ‘useful’ space offering little more than a very ‘defensible’ border, though it does have its attraction.   It provides shelter for some birds and critters, including rats, unfortunately, and fruit to those interested, while posing a minimal weed/seeding hazard to other landscapes.  It is a very simple landscape.

We can do much better than we have been doing with our landscapes…we have to!  It is incumbent upon each of us to grow our landscapes well, whatever they are, whatever they demand of us.  Our inability or unwillingness to do this is symptomatic of a society today that doesn’t  place priority and value on life, first!  (If you are reading this, you probably aren’t part of this ‘we’.)  The fact that we don’t have the time, resources or interest is indicative of how far out of balance our own lives are.  This isn’t a new phenomenon.  I don’t mean to shame or blame anyone here.  Modern societies have long been out of step.  We place a premium on our personal freedom, the idea that we have moved beyond nature, that technology will do for us whatever we need.  Nature will keep ‘chugging’ on without us so that we can devote ourselves to our more personal goals…and so ‘nature’ has been left largely on its own as if what we do will have no significant or damaging effects…but that isn’t really the way it is.  So, what do we do about that dead weedy lawn out front? Continue reading

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The Opposite of Freezing: Plants Have Upper Limits Too

It’s Sunday, July 30, and 87º outside, our forecasted high.  We’re at the front end of a forecast that is calling for two days over our record highest temperature ever recorded in Portland.  I’m looking at it now, Monday, the 31st calls for 92º, August 1 for 99º, 108º, a record, on the 2nd, 110º, another record, on the 3rd, before ‘cooling’ to 105º on the 4th and 95º the next day.  Our average high for this time of year is 82º.  The current record is 107º set on Aug. 8, ’81 and matched on Aug. 10, ’81.  That may not seem that high to people in the SW, but it is here and here is what matters.  Temperature is a local phenomenon.  It’s okay if we whine about it.  It’s hotter than we’re used to.  Hotter than what the local native flora and fauna are ‘used’ to.  For native species it’s not just about preferences, though we may use that word when we talk about their requirements and limits.   Continue reading

Manzanita, Rock Roses and Friends: The Strength to Stand

Choosing the right plant is not an easy process.  We pick a design theme, make sure our plant choices are a good match for our site conditions, are compatible with their ‘bedmates’ and won’t become overly burdensome, in terms of the maintenance we are able and willing to perform.  There are a lot of variables here.  Our expectations of how a plant performs in the landscape, as individuals and as a composition, are important as we assess their performance over time and decide how we will respond to them.  Many of us are attempting to create gardens that require less of us in terms of maintenance, that fit the conditions on the ground with minimal intervention on our part.  We may chose to create a xeric garden to minimize or even eliminate supplemental irrigation.  If we do, the plant choices we make, their spacing, the size of plants we purchase, even the timing of the planting and the soil prep we do, are all important in our success or failure.  While we attempt to keep our specific site conditions and our goals in mind, we need to be prepared for the extremes of conditions, like weather, that can occur occasionally, even if only once every several years.   Continue reading

Failing Landscapes, Failing Practices: A Look at Tri-Met’s Landscapes and How We Could Do Them Better!

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I include this photo, taken beneath the west approaches to the Marquam Bridge, an ODoT property not Tri-Met, as a reference for what is commonly found in transportation rights-of-way. This is not a problem solely with Tri-Met’s landscapes. It crosses the southern end of South Waterfront Park which was one of my responsibilities for 15 years and so I’m familiar with its level of care or lack thereof. The nearest portion, to just beyond the nearest piers, was entirely neglected for the entire period except for where I cut it down to reduce the amount of weed seed I had to deal with in the Park. There is literally nothing that was intentionally planted in the entire space. It is a landscape composed entirely of weeds and it is possible because landscapes for ODoT are of an extremely low priority. It is the neighboring properties that bear the brunt of their decision. It will be interesting to see if they come under increasing pressure over the years as the expensive and undeveloped properties to their south are developed. Currently the Knight Cancer Institute is developing a hundred yards or more away. The Marriot Residence Inn, immediately to its north, has had no effect on its level of care.

About a year ago I posted a series of three articles on Tri-Met’s landscapes along the new Orange Line.  They were a critical assessment of their design with many photos and explanations for my criticisms.  I had a brief correspondence with the project manager after the first two before he stopped responding.  I had asked about the maintenance schedule that they had with the contractor who would be doing the work.  I did not receive it.  Part of the reason was mine, as new ideas came up for me, my interest wavered and I moved on.  Still, I’ve never received anything.  Now, a year later, I decided to reassess the first portion of the landscape that  I wrote about, as it is a section I regularly walk and ride by bike to downtown or to just get out.  I would encourage readers to see my previously posted reviews. Continue reading

What Really is a Sustainable Landscape & Why it Matters

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I took this at Cape Horn in early May ’15 in one of the ‘wet’ woodland ‘terraces’. The native Delphinium gives it a fantastical appearance. If we could create this landscape anywhere in the City I can’t imagine that it would withstand the level of use and inevitable abuse it would receive let alone the ‘weed pressure’ it would suffer. Perhaps there are a few places that such a landscape could work but it would require that we have all of the surrounding landscapes ‘under control’ and that we educate the public so that they would understand and respect it enough to stay away. Our numbers alone even if most behaved themselves would make its survival difficult.  Ultimately, this is just what is necessary, re-establishing the public’s relationship with nature and the wild world.

(I’ve made earlier postings on this topic, but this piece actually predates those.  I wrote this in 2013 while still working as a horticulturist for the City of Portland Parks and Recreation as a member of a Bureau committee that was working to define ‘sustainable landscapes’ so that we could begin to make our policies and practices more consistent with our ‘desire’ to create sustainable landscapes and protect the relatively intact ones that remain.  This was a difficult process.  We spent a lot of time discussing/arguing about what constitutes a sustainable landscape and ultimately the direction that Parks should be headed.

There was a large divide between those of us who saw ultimately, that the only truly sustainable landscape was one that recreated those native landscapes that preceded the massive changes that European Americans brought with them, so that our efforts should be on these, and those of us who, having spent much of our professional lives in the field doing maintenance in created/urban landscapes, arguing that these new landscapes played a necessary role in the modern world and that our designs and maintenance of them could be moved in a more ‘sustainable’ direction.  These urban/functional landscapes, whether for active sports, community gardens or even many passive uses, provide places and venues for activities that native landscapes cannot.

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There is space and need for many different landscapes in an urban area. This is in the garden at South Waterfront Park along the Willamette River and is intended to be a contemplative refuge from the business of the city. It is layered and carefully orchestrated though its goal is more aesthetic than to be a ‘natural’ plant community. It requires considerable regular ‘grooming’ and editing to maintain in order to show off the plants to their best advantage. This garden was designed for multi-season interest especially through the summer when our native Willamette prairie landscape slides into dormancy.

The organizational structure of the Bureau has been built around three primary landscape ‘types’: ‘natural landscapes’ which tend to be larger and border more densely populated sectors of the City, ‘contrived landscapes’ that are dispersed throughout the City and serve the more traditional Park functions for sports and more casual social use and the ‘enterprise landscapes’ of Golf and PIR that serve very narrow functions and depend on those uses for much of the revenue that supports them.  These are operated and maintained by discrete groups within the Bureau, have different cultures and priorities and view sustainability very differently.   Because these are all in a highly urbanized area the degree of historical disturbance and the continuous pressures that a concentrated population apply to them, they can never by truly ‘sustainable’ in that they will always require our active stewardship to counterbalance these pressures.  This is not to say that we give up on the idea of balanced/dynamic landscapes of appropriately chosen plant communities.  We just need to remember that these are urban areas and be good stewards of the land.  We can even move ‘high use’ landscapes in a more sustainable direction, both in their design and in their maintenance.  It is incumbent upon us to do this to ultimately minimize the pressures put upon them and natural areas by weeds, invasives and human use.) Continue reading

Losing Our Urban Landscapes: Sustainable Goals and Our Crisis in Leadership

The Brooklyn switching yard. These areas must be kept clear. The fence line to the right, next to the container yard, is typical, here filled with common weeds, aggressive invasives and Tree of Heaven.

The Brooklyn switching yard. This ‘landscape’, in a modern utilitarian sense, is ideal.  These areas must be kept clear. The fence line to the right, next to the container yard, is typical, here filled with common weeds, aggressive invasives and Tree of Heaven…and it doesn’t matter.  It works and that is the priority.  Whatever results elsewhere…is not.

The following is intended as a template for action or a beginning point for a discussion that is long overdue.

Landscapes are more complex than most people realize.  They can go seriously awry in a very short time.  Undisturbed native plant communities are relatively stable and are able to respond on their own, as they have for millions of years…if the disturbances they suffer are relatively small.  Unfortunately these plant communities have been decimated in urban and most rural agricultural areas severely compromising their abilities to respond in a positive and effective manner.  The addition of invasive species to the region puts even stable, undisturbed plant communities at risk.  Because we are not all ecologists, or even gardeners, what can we realistically do to stop or reverse this process of landscape degradation?  The decline of our landscapes is linked to a long history of practices that have ignored the value of both our native and contrived landscapes, a belief in a right to ‘dispose’ of the land in whatever way we so choose and our denial that this destruction matters.  We have done this through our land management practices, our designs and the uses of the land itself even those that may seem unrelated, many that have become automatic in our society and are directly related to how we live, work and play today in the modern world.  Our active threat is inherent in the way that we do business.  Our attempts at correction are, too often, limited to only slight modifications that do not put any undue ‘pressure’ on our local economy, business or the privileges that we have come to see as ours.  We are a society that has, in short, become disconnected from the realities of life at the local level and what is required to support it.  We see a limitless nature that is there for our use.  Whatever we may need, we believe that we may merely buy from elsewhere, an elsewhere that is limitless though undefined.

To turn this situation around, or to make significant improvements, requires that we examine what we are doing now, that may be working against the goals that support life and landscape,…and stop.  We have to stop doing the things that are working to continuously disrupt the ‘healthy’ functioning of the landscape.  If we don’t do that then all of our attempts at improvement, all of our tweaking of our system, will come to nothing.  We cannot ‘save the patient’ with good thoughts while they bleed out. Continue reading

Summer Tree Failure

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A failed Norway Maple on SE 49th. This picture was taken June 28th, five days after a big rain event. You can see that this tree has been struggling for some time as evidenced by the dead branches still in its crown and the stressed flagging leaves up there. The girth of the trunk is greater than the width of its planting space. It is pinched beneath the overhead lines and the requirements for street trees regarding road clearance. It’s height has been ‘controlled’ and limited over the years.

Trees fail all of the time and when they are older, this can be quite spectacular, or devastating, if your car, home or an individual have the misfortune of being in the its path.  Like most people I used to believe that most such failures happened as the result of storms, and many do, but it is relatively common for trees, or major limbs, to come crashing down with calm conditions in the Spring. The new flush of growth brings with it a great deal more tissue and water weight than a tree in active growth has previously supported or, for a tree struggling, compromised by the burden of significant rot in its core and/or limbs.  Look at any tree and look at its girth, its canopy spread and on many species, its long, often horizontal limbs and try to imagine their weight.  To help with this fill a couple of buckets with water, lift them and try to hold them horizontal away from your body.  Trees are static structures, comprised of countless overlapping fibrous layers, much of it hard and rigid with a great deal of compression and torsional strength.  The were ‘born’ for this.  Few of us would last for more than a few seconds trying to support so much of our own weight on extended arms.  We shouldn’t be surprised when they fail, even as elegant and as well ‘engineered’ as they are. Continue reading