Category Archives: Horticulture

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

Bromeliaceae and Dangerous Plants: Adaptation, Climate Change and Gardening in Portland

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I don’t know what this Bromeliad is, but it is statuesque, the inflorescence reaching well above my head. I took this shot next to Burl’s ‘chateau’ at Rare Plant Research just south of Oregon City. He moves a lot of tropical exotics in and out of his greenhouses every year. This is what a lot of people think of when they picture a Bromeliad.

I awaken and come down stairs at about 7:00 am…it’s a warm 66ºF outside.  I was up late last night, until after 12:00 am, keeping the air flowing through downstairs in an attempt to cool the house.  This is on the warm side for us here in the summer.  On rare occasions our lows can drop to as high as the low 70’s…such temps tend to occur more frequently in more recent years when ‘heat lows’ settle in around us and we suffer through ‘heat alerts’, whenthe air stagnates and turns ‘brown’ and we can become caught in one of those cycles of days where our highs remain in the upper 90’s and low 100’s.  Our all time record high of 107º, in August of 1981, was during such a cycle that I had the privilege of experiencing as I was here in Portland visiting a friend and attending my brother’s wedding.  On the 6th it hit 99º.   The high rose the next day to 102º, 105º on the 8th, 104º the next, 107º on the 10th, the humidity at 15%, then cooling to 97º on the 11th.  I remember taking turns trying to cool ourselves, without any air conditioning, submerging in a tub of tepid bath water, Continue reading

What to do about Bamboo?

[Please note that I wrote this in 2004 as an article in the HPSO Bulletin.  A recent FB posting has prompted me to revive/revise and repost it here.]

My first significant relationship with a bamboo,15 years ago, (this was the summer of ’89 when we moved into our current home) was a fatal one.  Phyllostachys aurea, Golden Bamboo.  I had heard all of the usual stories, yards lost, asphalt heaved and cracked, good neighbors gone bad.  Our new house confronted me with several problems, that I knew would get worse if I put them off.  It was another example of a homeowner picking the wrong plant for a screen, or failing to take the precautions to contain it.  With my limited knowledge and biases I had no doubt about what I needed to do.  I got my shovel and chased every rhizome down.  I was thorough and a good hunter, none survived. Continue reading

Palms, Bananas, All Monocots…Oh My! Their Similarities and the Differences that Distinguish Them From Dicots…and why this should matter to you!

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I use a lot of Monocots in my garden, among them in this picture are the Colocasia esculenta ‘Black Magic’ with its huge dark velvety heart shaped leaves, Arundo donax ‘Variegata’, the Giant Reed, whose clasping leaves show us that this is a grass not a bamboo and the white speckled, green, heart shaped leaves of my Zantedeschia x elliotiana ‘Flame’ just behind the reaching stem of Arundo.

Many gardeners are self taught and haven’t formally learned Botany, the science that helps us understand plants in a more formal, academic way, though they may be excellent ‘gardeners’ in terms of their growing of plants.  Botany provides a pathway toward the understanding that many of us crave, that for others is an unwanted burden..they are happy with the doing.  For them the task of learning botanical latin, binomial nomenclature and the classification system by which we organize and study the various species, understand their structure, development and common history…is of less interest.  No doubt a good many fall somewhere in the middle.  I have always been among the more curious ones with regards to this. 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

The Strength to Stand: Surviving the Load of Ice and Snow in Portland

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The morning after the big snow along the front of my house. To the left, splayed out and weighted down, is my Butia capitata. This one, from Argentina and not used to snow, had me worried, but it sprung back. The Oleander to the right, next to the sign, was bent down to the ground from its 8’+. Further back is one of my Chinese Windmill Palms, Trachycarpus fortuneii, bent under a snow load it is used to from high in the mountains of southern China.

Many of us who garden in the Pacific Northwest, and especially those of us in Portland this year, will be visiting our garden centers and favorite nurseries this spring and summer with a little more anxiety and need as we look for plants to replace those that have succumbed to this winter’s cold, ice and snow loads, all of which were more severe than what we have come to expect here.  But before we pull on our boots and don our rain gear to head off for shopping there are several questions that we need to consider before we make our purchases.  Not all of us draw up plant lists, but most of us at least carry in our heads a wish list of plants we have seen in other gardens, in magazine spreads and while on vacations, but if we want to avoid some major mistakes and move our gardens toward the kind of landscapes that we really want, we are going to have to put on our reality goggles and critically assess our choices…that is, if we want to avoid unnecessary losses in the future. Continue reading