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?

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Weather is always full of ‘anomalies’, odd little data points popping out from the overall trend. Last year, a mild winter after the previous, frigid for us, winter of ’16 -’17, still set record low temps on two February days, 23º on the 21st and 24º on the 23rd, while this year, as consistently cool as it was, on nine days saw lows with warmer than the ‘normal’ low. As far as highs go, we were above our normal high on only one date this year, on the second we hit 50º, when the normal was 49º….We never came close to breaking a high temp record as we ranged from 8º to 43º below our recorded daily highs for the month.  What may be the most unusual fact about February was that half of the mornings saw freezing temps, nothing extreme, other than the frequency.

It was not a cold February.  We set no record minimums and in fact came close only a few days.  Those two days we dropped to 23º were 8º and 3º off of the daily records.  The closest we came to setting a cold record during this stretch wasn’t recorded until Mar. 2, when we recorded 26º, 1º short of the record, that record itself wasn’t all that cold compared to others for nearby dates.  While weather is comprise of a string of moments, of recorded conditions, our study of it breaks down into probabilities and patterns.  As we approach the Spring equinox, as the relative position of the sun moves northward, the likelihood of freezing temperatures drops.  There’s nothing surprising about this.  Each consecutive day adds a little more time for the sun to heat us here with sun slightly higher in the sky, a more direct angle for heating the Earth’s surface in our local area.  The range of high and low records, these charts, just give us an idea of what to expect.  Probabilities are highest that temperatures will be in the normal range.  Records should be relatively rare.  When we see them being set or approached too frequently we know that something is out of balance or that perhaps there is some other larger cycle at work that we haven’t considered.

Here I’m going to talk a little about ‘normal’ temps, in the world of NOAA, the National Oceanic and Atmospheric Administration, the federal weather folks, and what that means.  Normal is a statistic, not a magical boundary.  Abnormal, those temps outside of the ‘norm’, don’t connote or mean, that there is any ‘wrongness’, it is just a statistical artifact that labels something as ‘outside’ an expectation.  On most days, for most instances, there is a tendency for conditions to occur within the ‘limits’ of normal.  The ‘normal’ band of green on the chart illustrate this for each month and is built up from recorded temperatures over the recent 20 year period.  For example on those coldest days, Feb. 6 and 7, where we recorded 23º, the normal minimum was 36ºF.  Over the last 20 years the average low temp for that date was 36º.  They got this value by averaging the minimum temps over 20 years for each day.  The table shows this average for each day and it indicates a very stable cycle through each month.  The ‘flatter’ the bottom of the green band is, the more historically consistent the temperatures have been.  The ‘narrower’ the green band is the narrower, the more consistent, the daily swing of temperatures has been.  Wide fluctuations in the red or blue bands show the range of temperatures and give an idea of how ‘volatile’ weather conditions have been and suggests a range for what might be possible.  Averages always diminish the extremes. 

When we record a temp below the norm, it is not unusual and a look at their chart for each month will show this with the records for each date setting the thus far recorded limits for each date.  It would be freaky in fact to live where days followed very closely this average, something like the winters in San Francisco, where its location on the peninsula surrounded by large bodies of cool water moderate all its temperatures.  As you would expect, as recorded temps get closer to their record values for a date, their frequency and probabilities of them occurring, diminishes, always keeping in mind that new records can be set, though their likelihood is less. 

Our weather occurs within a limited, ‘open’, global system, as energy, in the form of heat from the sun is added to it, continuously, warming the whole system, the heat moves around in patterns from warmer to colder areas, losing it out to space in perfect balance as the Sun ‘feeds’ it.  Our atmosphere serves as an insulator protecting us, and the surface, from catastrophic daily temperature swings as the Earth spins on its axis as we expect.  The ’tilt’ of our axis shifts the ‘focus’ of the sun’s energy north and south, seasonally, as we revolve around the sun, our axis remaining stable and fixed shifting the intensity and patterns of flow of that heat as it seeks the elusive goal, stability and uniformity.  Compared to the vast majority of the volume of space even the most extreme temperatures on Earth, are moderate.  Life can exist, certainly as we know it today, with essential liquid water, in only a very narrow range of temperatures.  In more recent human history we have been adding significantly more of the insulative gas, CO2, to our atmosphere, which has slowed the Earth’s ability to radiate away heat and the whole string of events that follow that has been set in motion, a process that won’t move in a necessarily linear and even manner.  The warming is expected to cause more chaotic swings as the system gets ‘pushed’ out of balance…. 

Normal varies from place to place along with the variation of physical differences associated with place.  Normal for the PDX location will not be yours or mine, but in the Portland area it will be relatively close.  My winter minimums tend to run warmer than those at PDX though not always as does my precipitation and wind.  Over Portland’s cold period, I experienced freezing minimums 21 times, five fewer days than PDX.  My minimum over the entire period was 26ºF on Mar. 4 when PDX recorded 24ºF.  On Feb. 6 and 7, I was 3 and 4 degrees warmer.  Does this make much difference?…hard to say.  As I said, when it comes to plant survival, it is all about patterns and a plant’s capacity to respond to those conditions.  Many horticulturists have noted that cold extremes, that come later in the winter, tend to be easier for most plants to respond to and that cold extremes that come in late Fall early Winter can be more deadly and a consistently ‘ramping’ up of cold temperatures better ‘prepares’ a plant to tolerate extremes.  The ‘yo-yoing’ of daily temperatures that we frequently experience here in the PNW can be deleterious and can effectively reduce a plant’s maximum cold tolerance.  Next I’m going to do a quick review of our winter preceding February.

Our winter was shaping up to be maybe the mildest that I could ever recall in my 34 years here.  In November, on the 9th and 19th, PDX recorded 32ºF…no other freezes, for the month.  On only 13 of the days did we record temps below daily normals as it declined through the month from 43º-37º.  I did not freeze at all at my location.

In December, PDX recorded four minimums of freezing or below, with the coldest at 31º.  Seven days were below the norm which ranges narrowly from 37º-35º.  Again, this was a milder than normal month.  I did not freeze at my location.

In January, PDX recorded five minimum temps of freezing or below with the coldest at 29º on Jan. 1, when I hit my first freeze.  My second and only other freeze, was the next night, both just below freezing.  PDX normal minimum ranges from 35º-36º with January historically our coldest month.  On ten days PDX was below the normal range, me slightly less so…still mild.  Through January Portland was in the midst of a zn 10 winter with one date pushing it into 9b which ranges down to 25ºF.  My own two minimally freezing temps kept my garden in zn 10! and it showed with even a casual examination. 

There was damage.  Most of it was either attributable to cool temperatures that greatly slowed plant metabolism and any consequent growth, impairing a plant’s ability to replace damaged foliage, and the wind I typically am exposed to out of the south, which tends to tatter and shred my larger leaved plants, having a greater effect on those from warmer climates, and the other factor being that of ‘radiant heat loss’, that phenomenon that can occur on clear calm nights when the surface temperature of leaves can fall below the actual air temperature, this is what causes frost to form on your windshield.  Plants, like Cannas and Arundo donax, are particularly sensitive to radiant loss, their tissues when damaged, then desiccating and turning crispy brown before many other plants in my garden.  This all changed of course, with the arrival of February’s cold.

The Movement of Heat

Heat moves in one of three ways all of which are a factor in our comfort and the well being of our plants.  ‘Solid’ bodies or masses radiate heat away which can be absorbed by colder bodies.  This is what our very hot sun does, radiating heat, in the form of light, electro-magnetic energy, away, seeking a balance.  It passes through space without heating it, converting some of it to heat when it strikes solid bodies asteroids, moons and planets.  It does this on Earth heating masses that in turn radiate heat away to other near by bodies.  Here the atmosphere, with its moisture and gases, contains some of it, slowing its loss, moderating the temperature of the Earth’s surface.  The moon, without an atmosphere to impede the movement of heat has swings of hundreds of degrees as its surface moves in and out of the path of the sunlight.  (There is no atmosphere or water bodies to move the heat around on the moon as wind or ocean currents.)  Heat radiation happens at all scales, on large and small bodies.  Think about those winter periods of long sustained cool/cold weather when the ‘body’ of your house cools in response, it is radiating heat away, and, even though we heat our homes, and within the inner spaces, the air, may be heated to 70º, it continues to radiate away heat and we can still feel cool inside, because our bodies are radiating heat, transferring heat toward the cold of our homes mass while it radiates it outside and away to the cold sky.  (Our homes also lose heat as a result of convection, the wind passing by its surfaces drawing heat away.)  

Heat is also lost through conduction, which is heat moving through a solid mass from warm to cold.  This can be a very rapid process, depending on the material that composes the mass, like the metal heat element on your stove top to the bottom of a pan.  It also ‘explains’ why when you stick out your tongue when its -20ºF nothing much seems to happen…at least not immediately, but when you touch it to a solid, cooled to the same -20ºF, like metal, which conducts heat very quickly, your tongue freezes.  This helps explain why the soil of your garden, when exposed to freezing temperatures doesn’t itself freeze immediately.  The heat from deeper down is conducted closer to the surface, moving toward the cooled surface.  Sustained freezing temperatures are required to freeze the upper soil level and even longer periods are required for it to go deeper.  This helps protect the crowns, the meristematic tissue of your plants, from quick cold snaps.  Remember that heat is conducted through ‘solid’ mass.  A mass like loose mulch, or your down jacket, creates insulative air pockets that slow both radiation and conduction.  Porous soil, with a loose mulch is a much more effective insulator than is heavy, compacted soil without mulch.  These pockets also inhibit the movement of air and water, preventing them from moving heat through ‘convection’ which requires physical movement.

The third mode of heat transference is convection and occurs only in liquids, like water, and air…not solids.  The component parts, the molecules of air and water, are in continuous movement relative to each other, their molecular bonds strong, but the separate molecules unbounded, in other words, fluid.  As volumes within a liquid or gas heat, they rise…as they cool, they drop.  This sets into motion what we call convection currents which is a cycling from warm to cool and back again, in cyclic patterned flow, transferring, gaining and losing heat continuously.  As the sun, the heat source, warms the Earth’s surface, its waters and air, they are set into circular motion moving from warmer to cooler regions within the space.  This happens on a worldwide scale just as it does in much smaller, contained volumes, like the water in a pond and the air in a room.  There is a vertical component to this cycling as well as a lateral one, warmed air moving out away from those areas of the Earth’s surface receiving the most energy, changing with the seasons and even time of day.  Within these cycles the warmed air or water, rises and later cooling, drops and returns, away from warmer areas, toward cooler, the cooler water and air dropping and moving back towards the source of heat as the warmer air, set in motion, moves away.  This creates a very complex pattern of movement that is quite stable within a range, but very difficult to predict narrowly, especially when too much heat is added and the system moves out of balance as has been happening in more recent years at an accelerating rate.

[The sun has not varied its output significantly over this period, but the whole system has been pushed out of balance as the atmosphere itself retains more heat.  The warmed atmosphere, in addition to containing more energy, picks up more water.  This ‘wetter’, energy laden air, is capable of releasing it in more severe weather events around the world, not evenly, but in response to the many factors that influence our daily weather. Since the sun won’t be reducing its output any time soon, thank god, we need to create ways to recapture the excess Carbon in the atmosphere to reduce its insulative value to keep the Earth’s heat from increasing as it surely will, even if we stop adding to atmospheric Carbon.  It is not just a matter of reducing CO2 production, but a necessity of recapturing it and storing it away.  The Earth as a system has functioned for several billions of years largely in balance before our petroleum habit which has fueled resource extraction, the removal of forest and the reduction of life in the Oceans, in which nearly unimaginable amounts of Carbon were once sequestered…scientists have actually calculated this.]

From this comes the trade winds and ocean currents which are in constant motion, and with larger, more stable patterns, over many centuries.  Smaller variations occur regularly, which set even smaller yet, generally shorter lived movements, into motion, yielding our changing daily weather patterns.  For example the Gulf Stream has for many centuries brought its relatively warm moderating waters to Great Britain giving them a mild climate impossible at the same latitude of western North America.  Should the Gulf Stream  become disrupted and change course, the changes will be catastrophic there.  Around the equator a seasonally consistent pattern assures the patterns of rainfall we’ve come to associate with tropical regions and other phenomenon like the equatorial band of the ‘doldrums’ where the heat tends to draw the air up while surface movement, wind, seems to stagnate.  Now days as more heat is added to the system tropical storms become more frequent and potentially more intense.  Closer to home is the normal cycling in the tropical oceans as they warm and cool which sets us up for El Nino and La Nina weather patterns at temperate latitudes, but as the overall global heat balance warms, these patterns begin to fluctuate, causing breaks from ‘normal’.  Another climate casualty appears to be the breaking down of the Arctic polar vortex this winter, the consistently strong, band of wind that normally encircles and contains the cold air at the Earth’s two poles, allowing an abnormal amount of polar air to spill down into the continents while warmer than normal air circulates up toward the poles.  (How does it do this, contain the cold?…in a way similar to the ‘air wall’ technology used in places like Costco where a large cooler is kept cold by strong directed air flow at the opening which slows the loss of cold air from within or similar ‘air doors’ at shopping malls.)  This ‘chasing’ of heat around the planet creates our weather.   Our weather is not some independent property of the Earth fixed and impeturbable, it is a direct response to the heat within the system of the Earth.

A Little Weather History

Our late, sustained, colder than ‘normal’ weather, has not been that unusual for us…it wasn’t that cold.  Historically, and generally, much of the Portland area has been in the zn 8 range or in more extreme, outlying cold pockets, sometimes down into the zn 7 range, but this old pattern seems to be changing, becoming milder.  In my 35 years here it has been a very rare occurrence to drop into the low teens.  I can only immediately recall one such sustained period, about a week in February of ’89 with below freezing highs.  There are still three record lows held by that ‘storm’ on the days of Feb. 4, 5 and 6 of 14º, 9º and 15º.  Broad leaved evergreens suffered and died across the area.  I particularly remember removing destroyed Escallonia and Choisya from Parks though others suffered damage.  Many other evergreens responded by defoliating suffering additionally by the accompanying winds that desiccated tissues.  Other records for February in the teens appear in the chart above over my residency, but I don’t really recall them, in ’95 and 2011, and there were likely other dates in the teens, but the chart only shows the still standing records, not the old records or all of the times temps fell just short.  And, of course, a quick check shows that every record daily minimum in January is in the teens and single digits, with one of -2ºF, the only negative, set in the abysmally cold winter of 1950, well before my time in Portland.  More sever cold, used to be more common here.  We’ve all seen those old photos of cars out on the ice of the frozen Willamette, even on the Columbia!  Interestingly, only two of those January records were set during my Portland residency and they were in 2017, remember…I certainly do.  Those two minimums weren’t flukes as that entire month brought colder than normal temperatures with more than a few below 20ºF.

As a region we’ve remained within the bounds of a zn 9a winter this year, not having dropped below 20ºF.  For you new arrivals, understand that this has not been normal, but of course our ‘normal’ appears to be changing.  You can not determine a trend from a single year.  Those of you who dismiss out of hand any plant that will not tolerate the bone chilling extremes of a zn 6 or 7 out of a fear of losing it to cold, need to reconsider as the plants of the cool/cold temperate regions, which comprise this group, tend to come from regions that are more polar in their latitude or are subject to the cold typical of interior continental areas and often tend to receive summer precipitation as well  The conditions here are different and your plant palette should reflect that.  Plants from cold temperate regions have different requirements and if we don’t understand this we can lose them as well.  

[Our climates in the US are warming.  A good indicator of that is the ratio of daily record setting high extremes to the number of daily low extreme records across the US.  This is the overall trend as the continent and globe warm, with the expected anomalies and variable ranges.  Some areas are setting as many as 20 record highs for every record low.  Over the last 20 years we have been setting roughly 2 record daily highs for every one daily low.  Here’s a link to an Associate Press article on the story.]

[It is interesting to note that having just come out of the winter period I’ve described that now, Mar, 18,19 and 20 have warmed to near record setting highs!  On the 19th Seattle set an all time record high of 79º for the date, the warmest March day for any date in 125 years.  An area of high pressure has parked itself over the Interior Northwest and Pacific Canada, allowing temperatures to soar to unusually high levels. The same day here we were 73º while PDX recorded 70º…the daily record is 73º!  Today, the 20th is shaping up to be even warmer having just approaching 72º at 1:30 pm…a new record high!.  These wide swings in daily temperatures over relatively short periods, from colder than normal to record highs is what many climatologists are telling us will become the new norm.]

Latitude and Cold

Latitude determines day length throughout the year as well as the effective length and extremes of climate due to solar incidence, the changing angle of the sun, the effective length of seasons.  The quality, the extremes, the effective length of winter, varies directly with latitude.  Latitude, along with elevation, landform and position relative to oceans and large bodies of water, effect the intensity of temperature throughout our seasons.  Winter can mean something very different from place to place and it involves more than temperature extremes and precipitation amounts.  Latitude determines the solar energy available to heat the air and surfaces as well as to power photosynthesis.  Climate and the pattern of cloud cover can decrease this through their ability to reflect away the suns rays.  Historically, over our winters, our regular cloud cover reflects much of the sun’s energy away with its reflective top surface while trapping heat beneath it, thus moderating our winters.  Latitude, works with climate and weather to help set these parameters for your garden and thereby what it can offer the plants you bring into it.

Each species evolved within a specific geographical range across a limited range of latitude.  Species are adapted to the conditions this sets for them, sometimes very narrowly.  Each species will have a differing ability to live outside of this range.  Whether or not you can offer a particular plant what it requires in terms of temperature extremes, latitude, by exposing a plant to ‘longer’ periods of cold than it is adapted to can stress it, just as taking a temperate plant and moving it to a more tropical location where warmth and sunlight can present an impossible challenge.  Temperate plants like Apples, for example, tend to be less productive as you move them toward the equator into regions without a pronounced and long enough cold period, stopping them from forming flower buds and precluding their ability to grow fruit.  Another plant, growing at high elevation at a more equatorial latitude, may be able to survive your minimum temps at temperate latitudes, but the fact that your winter at 45º may stress it for a longer period, with its shorter days while potentially exposing it to soil fungi and bacteria, may bring about its demise.  The metabolism of all of the plants and soil organisms slows in winter, the populations living within soil can shift radically changing the soil conditions below. This can be a factor.

Plant Response to Cold

A few words on plant responses to cold, a topic I’ve covered more extensively previously…whether you attribute a plant’s hardiness to its genetics or some other pattern, understand that plant health is complex and a healthy plant, like you and I, or any other organism, is considerably more tolerant to extremes of conditions when it or we are healthy and robust.  We should not think in terms of what a plant will survive or tolerate, as that is focusing on the wrong end of the ‘horse’, but on whether we can realistically provide the conditions under which the plant will thrive.  A plant tag that tells us hardy to zn 7b does not tell the whole story.  The more our growing conditions compromise the growth and health of a given plant, the less hardy it will prove to be.  This is why it is imperative that a gardener understand their site, why we need to observe and consider it before we plant.  Well, maybe not before we plant anything, but we do need to understand what we have, how it’s doing and what that means.  We need to live with our gardens and not just rush out to impose a new plant or design on it because we may want to.  Many of our plants will die for us, prematurely.  This is a hurdle all gardeners have to learn to cross, we need to note the conditions and what we may have done or not done that helped lead it to its death.  We are an active and potent component in our gardens and they are not ‘plug and play’ despite what we may wish, and trying to create one that is, in which we have banished plant death, is naive and ultimately defeating.

Where did our plants come from and what were conditions like there.  This gives us a basic understanding of its requirements, beyond, sun or shade, moist, well-drained and its cold hardiness rating.  Plants evolved in complex relationships with other plants and wildlife, in other soils, at various latitudes and elevations, different degrees of maritime or continental influences.  Plants are neither abstractions nor fixed stable objects, they are dynamic and very much alive.  They vary widely in their adaptability, but they have limits and if their metabolic systems can’t function as they need them to, they can’t ‘run out to the store’ and buy what they need, though they can, effect conditions to some extent, by growing, modifying their own growing conditions, as will their neighbors, but only so much….They are very dependent on everything around them.  We ourselves are capable of living only within a very narrow temperature range, much narrower than the plants of most of the temperate world.  We get around this buy wearing clothes, seeking or building shelter and searching out what we need or doing so by trading with others.  Plants are limited by their being fixed to place.  They have already adapted to a much wider range of conditions than we have so we should respect the limitations that they have when we garden.


A shot of my back garden taken on Feb. 9, after a few days with freezing minimum temps and our heaviest snow of the stretch of cold, nothing compared to all of those up in the Puget Sound area.  Previous to this my Melianthus, Cestrum, Abutilons and several more tender Salvia, Senecio, etc., had actually looked good.  The Musa, Hedychium and Cannas had begun to decline earlier…this finished their leaves off…yup, pretty much froze them back.  This garden can look pretty winter desolate as I have relatively few plants that are part of the typical evergreen garden backbone, no Rhodies, my neighbor’s Camellias back me to the north on the right, no Pieris, Sarcococca, Nandina….I have one remaining dwarf Tsuga from my original planting, a couple Mahonia and a few Aralia, Phyllostachys, Pittosporum, Fabiana and just recently added back in a Cephalotaxus harringtonia ‘Korean Gold’, a Daphne odora ‘Maejima’ and there are sweeps of lower evergreens like Iris, Mondo Grass, Carex and Acorus that act as ‘knitters’.

What I do to Protect My Plants

What did I do this winter for protection?  First my true tropicals, those plants intolerant of freezing, which don’t really even ‘like’ to spend time below 50ºF, I moved into the basement where the temp doesn’t drop below 55º.  Here too I moved more recent divisions and cuttings that I was trying to coax more growth out of before Spring…and, yes, I have grow lights.  Some plants are shuttle into a darker basement corner, my goal not to push active growth, but only to preserve them.  Certain other plants I’d taken cuttings of because I didn’t want to dig, move and store the mature plant.  Interestingly, these all were still fine until the February cold really set in, specifically my Salvia chiapensis and Salvia africana-lutea, both died back by the middle of that month.  Surprisingly, a few like the tender Senecio mandraliscae, Blue Chalksticks, was still alive in a large pot sheltered under the porch roof except further out where the ends collapsed.  Another one, in the ground, next to my front stairs with a few Agave relatives and a Butia palm, I covered with an upturned pot on the coldest nights…and it may be okay.

Many of my plants that I grow in pots are damaged by winter wet more than they are by our typical zn 8b cold, of course I selected these for this and I’ve lost some of those I didn’t understand fully before acquiring them, it is true that dead plants tell no tales, but we need to remember them and their ‘whys’.  These, my porch dwellers, with a couple of exceptions, spent the entire winter out, under the roof, protected from the rain, which, overall, has been significantly less than normal, (we’re about 6″ behind normal, about 25%) as well as from possible radiant heat loss.  The exceptions were a few zn 9b Agave, Aeonium and a handful of succulents I was concerned about should the temp drop below 25º…bringing them right back out after the immediate threat was gone.  Even so, my potted Mediterranean Fan Palm, several Sabal palms, Puya, Hechtia, Dyckia, Fascicularia, small Oleander, Fig, Bilbergia, a Chusquea cummingii even my Cycas panzhihuaensis, reputedly a zn 8a plant and the cold hardiest of the Cycads, all spent the entire winter outside.  My Oaxacan Dioon spinulosum, as a Cycad with a sub-tropical, zn 9b ‘disposition’, went into the basement early, it’s fairly big and not the easiest thing to move with stiff somewhat pokey ‘leaves’.  I also have an increasing, but still small collection of ferns, in pots, looking longingly, but so far unsuccessfully, for in ground homes, including several Pyrrosia spp., though I do grow P. lingua and P. hastata in the ground, Blechnum chilensis, Dryopteris sieboldii, Woodwardia unigemmata and others that I baby wanting them to grow to greater size…so for me, intention comes into the decision as well.


Nothing fancy here for storage. This all faces south with about 7′ of roof overhang on a concrete slab. There is living space beneath which probably contributes a little bottom heat. This is very wind protected. I have two other protected areas, beneath roofs where I’ll move larger pots that I don’t want to move up and down stairs. This is where winter dry/cold tolerant plants hang out,  A large Agave colorata, which had its bloom cycle interrupted by winter, is in the far corner on a dolly which I wheel back and forth.

I have other indicators of the winter’s mildness, my Grevillea x ‘Pink Pearl’ never stopped blooming.  It died back by 30% in the winter of ’16-’17 having passed dangerously close to losing the entire plant…it rebounded with robust growth!  G. miqueliana was undisturbed as well.  My Tecomaria capensis ‘Hammer’s Rose’, experimental for me, was still hanging on to flowers in its spot on my south facing retaining wall coming into February, hopefully it will rebound as it took about a year at that site to get established.  I’m hoping for a much bigger show in the future.  At the base of that is my Iris unguicularia, (sorry Paul, I can’t remember the name you said they assigned to this one time subspecies now species!), blooming better than it ever has over its more than dozen years there, held back by neither cold nor pelting heavy rain and snow.  The cold did eventually knock off the leaves of my Cestrum x ‘Orange Peel’ zn 7 and C. fasciculatum var. ‘Newellii’, one site rated as zn 9 another zn 8.  The ‘Orange Peel’ has come back from much colder and this year the stems themselves seem mostly undamaged, though the plant is getting large and could use a ‘cutting back’.  The ‘Newellii’…we shall see.  It is a much less robust plant and I wish it was more floriferous here, so if it is gone, I won’t be replacing it.  I dug and stored it several years running.  My several Arailaceae, Schefflera delavayi, Pseudopanax ferox, Metapanax delavayi, x Fatshedera i. ‘Annemieke’ and of course Fatsia japonica ‘Spider Web’ and ‘Camouflage’, didn’t even blink.  I don’t expect much blinking amongst my herbaceous garden members either with the still relatively mild temps and somewhat less soggy conditions other than perhaps my South African Wachendorfia which I know should be in a little better draining soil (last year I dug and divided in Fall and held in pots until Spring, it grows like a bit of beast that way.)

I’ve been gardening here for 31 years now…this is not the garden I began with, just as I am not the gardener I began as.  Over most of those years I also gardened in many Park sites across the City as a horticulturist.  Non-gardeners have a tendency to see a garden they like and want to import it in part or in whole to their own location, maybe mix it with pieces of others they like too, and then sit back and enjoy it in its ‘static’ glory and finality, fixed and forever…we all begin somewhere.  They have a lot to learn.  I’ve worked in the landscape/horticulture field for 40+ years and have learned that everything matters and you don’t always know how much.  What works in one garden is not always directly transferable to another, even one close by.  The variables are many and they way they impact one another complex….This shouldn’t discourage you.  Hopefully, it will pique your curiosity.  You can never know too much about your site, and the micro-sites it contains, just as you can never know too much about the plants that you invite into your garden and their relationships with one another, whether exotics from around the world or a native a seller guaranteed you success with.  We begin to understand that even ‘bulletproof’ natives have their requirements and the conditions on our site may not be so natural after all, as our attempts at gardening can be more akin to a bull in a china cabinet.  There is always more going on than you might think and I believe that our plants ‘know’, at some basic level, how much we pay attention, how much we care.

In time we begin to see micro-sites and shape them, developing a sense for how and what ‘kind’ of  plants might fit it, searching our memory and querying friends for one that might be better suited, modified by its established neighbors, that pull excess soil water away, but not too much, to keep it just like ‘Goldilocks’ would like.  Gardeners commit to their gardens for the long term.  It is like any other such commitment, yes, even that one, and just like it we get everything that comes with it, the weather, the neighbors and the wildlife.  We can look at these as obstacles to overcome or take them as a given, use them to shape our gardens into something special and unique…not ‘boilerplate’.  Gardening forces us to adapt and give up our preconceived notions least they frustrate us throughout our gardening lives or drain our wallets as we relentlessly try to overcome them.  Climate and weather are part of this necessary adjusting and our maturation as gardeners.  Those with a ‘green thumb’ seem to be inclined this way, observe and adjust, all while staying patient, curious and expectant.  Those who don’t, keep throwing money and plants at a landscape without thinking too deeply about what is really at work in it.



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