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.
We are just beginning to emerge from one of these less normal ‘testing’ winters and many of our gardens are suffering losses. We have two choices, to plan for the ‘normal’ variations in our conditions and accept the losses that are occasionally visited upon our gardens or we severely limit our plant pallets in a conservative attempt to prevent any such future loss. Many of us will find the later unduly limiting and will risk a degree of loss. In my previous post I spend considerable space discussing many of the variables that influence a given woody plant’s ability to with stand the loads put on plants by ice and sticky wet snow. No plant is ‘bulletproof’. The sturdiest of plants can be compromised by growing conditions and the care and abuse they receive over the years and, weaker plants can be improved in many ways depending on the care they receive. Our care will never be ‘perfect’. It is important to keep in mind the plant characteristics that can either lead to success or failure when a plant is put under physical stress. The gardener will also have to decide for themselves how much damage they are willing to accept in their gardens, because most damage is not immediately fatal.
Our landscapes rely on woody plants to give them more structure and variety in height and mass, helping us literally shape our experience in the landscape and garden directly effecting the visitor’s experience. In temperate climates, such as ours, we often look to woody evergreen plants to do the same during our colder months when our deciduous and herbaceous plants ‘retreat’ until their Spring returns. When we make the decision to reduce our water use, to go xeric, we must change the palette of plants we choose from or be willing to live with gardens that suffer and under perform while drought reduces them. Our best, most appropriate, choices will be able to more than simply endure the conditions that they must live with, they should excel. Whether a plant succumbs to our local drought conditions of summer, or fail catastrophically under the load of snow or ice that our area subjects us to every few years, the result damages our gardens and landscapes.
I will be reviewing the performance of many of the plants in a landscape I’ve reviewed previously on my blog at South Waterfront Park and Riverplace, specifically, the xeric plantings that I began several years before I retired. Please review my earlier postings for a more complete review of their planting and performance.
Cistus corbariense has sprawled to densely cover the entire bed
Cistus x corbariensis
The first planting I’ll review I did not do, it was a result of a redesign to the recently completed South Waterfront Park when the adjacent roadway was reconfigured. About a dozen Cistus corbariensis were planted on a south facing slope next to the new sidewalk and SW River Pkwy. In 2000 the slope was cut back and made steeper. The Cistus were essentially planted into the fill soil that the hill was created out of during site construction minus the topsoil layer which was scraped away here. The dozen or so plants did well and over time filled in and eventually smothered the Kinnickinnick beneath it. This is a lower somewhat sprawling mounding shrub. Very little was done in terms of maintenance, no pruning or shearing, other than keeping out the most aggressive invasives, i.e., Clematis vitalba and Himalayan Blackberry. Nothing seems to have been able to compete with the planted Cistus. Often Cistus, when planted here in the Willamette Valley grow vigorously. These didn’t though they were steady. I attribute this to the slope, their southern aspect and and the poor rocky clay soil. They received some though not regular irrigation. Very often these plants ‘flop’ open here and can provide an opening for invaders when doing so. These did not. For 16 years +or- they have performed well. Under richer, better growing conditions they may not last so long. These were battered this winter by fallen Alder branches causing them to splay open somewhat, but very little breakage occurred. There overall density and ‘sturdiness’, a combination of branch strength and flexibility, has served them well.
Garrya elliptica ‘James Roof’
This is a tough plant. I only planted this one and it took a lot of physical abuse in the form of being tromped on and broken when it was young. It is growing high on the bank above the Willamette somewhat shaded by a Red Alder to its north so probably offering minimal protection from the snow. Keep in mind that all of the plants reviewed here received relatively minimal amounts of ice when compared to other parts of Portland, particularly, NE. Like all of the other plants in South Waterfront they have a foot or so of sandy loam topsoil on top of graded fill, fill that was the site of industry for decades and among other things is very compacted creating distinct layers that are resistant to both water percolation and penetration by roots…not ideal. The good news is that the snow and ice did nothing to this plant. At around 7’ tall it is relatively stocky, likely due to its abuse and its location on the unirrigated bank.
Arbutus x ‘Marina’ having suffered both vandalism and two winters that froze it at least partially back. It began as a single stem tree.
Arbutus x ‘Marina’
I’m a big Madrone fan. Over the years I probably planted at least a couple of hundred of our native Arbutus menziesii in various Parks, most of which never made it for a variety of reasons. I would routinely plant them in groups of three in the fall hoping at least one would make it. Sometimes it worked that way sometimes not. Somewhere around 2009 or ’10 I decided to plant three Marinas understanding that while not as cold hardy, they generally were more likely to establish and then grow more quickly. All three made it. My records are incomplete, but their second winter the cold did one of them in and hammered the other two resulting in plants that sprouted back from their bases with several shoots. They remain today, occasionally suffering winter cold damage. This winter they seem to have again survived the cold and have been unbothered by the ice or snow. They are ungainly and sparse looking bushes. They have since been passed in stature by by the surviving Pacific Madrones I’ve planted along the river. If I had the site I would try these again on a steeper south facing bank above any cold pockets. It would be interesting to see where these might be doing good around the City. A selection made in the San Francisco area, I haven’t given up on this plant as suitable for certain sites.
Quercus suber
Anyone who has ever seen a Cork Oak with mature bark, will inevitably remember and be drawn to this tree. I’ve seen them in the Lake Merritt area around Oakland and San Diego Botanic Garden most recently. The Elizabeth Miller Garden north of Seattle, has a specimen, still relatively small, that is beginning to exhibit the texture of more mature bark. I planted three of these here on the bank of the Willamette just north of the Marquam Bridge in South Waterfront. While still small they are beginning to exhibit their ‘treeness’ with an upright form, soft drooping branchlets and small cupped evergreen leaves, all qualities that ice/snow resistant woody plants often have. I suspect that they may have bent under their winter loads, but they regained their posture.
Arbutus menziesii, Pacific Madrone, another iconic and under planted tree in and around the Willamette Valley. Note the beer bottle to the lower left, this is a Park after all.
Arbutus menziesii
I love this tree, a ‘trash’ tree to industrial loggers. An occupier of many of our cut over forest lands and burns west of the Cascades, it can often be seen growing up in thickets, that show its attributes poorly. In the Willamette Valley it historically clung to steep slopes above the river and on abrupt rocky hilly knobs scattered around the Valley. I long ago saw this as an ideal tree for Parks near the river where slopes were sufficient, a tree that was often ignored by designers of big public capital projects in favor of those more typically cast as riparian trees like our native Ash and Alder, but many of these sites bake hot and dry in summer stressing bottomland trees. The Madrones are also much more difficult to establish in the landscape and to grow to larger size in the nursery. Public projects often specify larger caliper trees for instant effect. Madrone take time, but they can abide given the right conditions. A nice grove of them continues to expand in the sandy dry fill of Kelley Point Park. Once established, these are very tough and will continue on to maturity baring physical abuse, which they can often grow out of. Their achilles heel is supplemental summer water the application of which can be nearly instant death. Our penchant for watering landscapes is a death sentence for these. So their success is dependent upon equally tough xeric neighbors and a strict avoidance of summer water. While these have relatively large evergreen leaves, none of these smaller trees where damaged by the snow and ice. Strong branch angels of attachment and relatively slow growth help these out in addition to their relatively open canopies which provide less surface for snow and ice. To be fair, all of these are young small trees, a survey of mature Pacific Madrone, might suggest otherwise. Still, I would not hesitate to recommend this tree.
Cistus x obtusifolius
This is planted in three different beds in South Waterfront Park, the planting furthest south, suffers greatly from surface runoff from summer irrigation and winter rains due to the shallowly wave like undulations of the concrete esplanade which collects and ‘focuses’ water instead of allowing it to evenly sheet off from a more uniform edge. The plants in all three beds held up well to the snow and ice, but the overall health of of the southern planting has suffered due to soil moisture. The healthy stands have a tight rounded form with tiny evergreen leaves and have suffered no breakage or significant damage. The healthy plantings are raised slightly above the surrounding ground, receive neither runoff nor any supplemental irrigation. Under dry conditions I still think this is a superior choice.
Arctostaphylos x ‘Austin Griffiths’
This is a superior hybrid Manzanita, generally starting blooming in January. Our cold snap delayed it somewhat this year. It’s biggest problem seems to be its vigor and stature. It is not a small plant. Paul, at Xera, expects this plant to reach 12’. I don’t doubt that. This is the fastest and tallest growing of the species and hybrids that I’ve planted. There are 15 +or- plants in three different groups, two in the South Waterfront Park portion, the north end of which abuts the Newport Grill’s fenced garbage enclosure and a third grouping well north along the Riverplace Esplanade across from the marina. This northern grouping contains plants that are significantly smaller than the other two growing in the much poorer fill soil they have to contend with on the bank they were left with from the original, mid 1980’s construction. These plants are smallish and appear to be well rooted. To the south, growing in the compacted soil layers, the plants grow larger and more quickly, the result being, that one toppled completely over while several others visibly heaved the soil and undoubtedly breaking roots. I suspect that the better soil layered on top of the fill encouraged quick top growth, with the roots spreading shallowly versus going deep. It has been suggested that given our better quality soils here that it would be good practice to cut these back in their first years to reduce the top growth and develop a better root to shoot ratio. I suspect this is true, but I was reluctant to do this at the time. Planted further away from the esplanade and further down the slope, with a band of Spiarea and other plants between them and the esplanade, I was eager for them to get up so that they could be seen. Maybe a mistake in retrospect. My successor was going to see about attempting to re-establish these by trimming torn roots, righting and bracing them in place. Doing some kind of top pruning, thinning out the remaining branches on all of the taller plants weather toppled or not, would probably be a good idea. Other taller species and varieties, like ‘Dr. Hurd’, not planted here, would likely benefit from a similar thinning of their crown. Sometimes even a simple heading back of all of the stems might be beneficial to encourage rooting and more compact top growth.
Keep in mind that many Manzanita are ‘burl’ formers and can come back easily after fire or damage, from their well rooted burls once established, but whether burl formers or not deer naturally browse Manzanita. These two natural forces keep them more compact. The more vigorous it grows the more fire resistant it is, but the more palatable it is for deer. Remember, nature normally ‘prunes’ Manzanitas. Eliminating these ‘threats’ in your landscape can have repercussions.
Quercus wislizenii
I planted several of these California Interior Live Oaks along the bank, first up on the northern Riverplace Esplanade, two of which were quickly gnawed down by Beaver, which has resulted in a multi-stemmed evergreen shrubs and one of which has quickly been calipering up a nice trunk. The untouched plant was once surrounded by a planting of Ceanothus, the other two were more in the open where they were more exposed to the Beaver. The trees in the South Waterfront portion are more widely scattered south of the Newport Grill location and being younger, are still much smaller. None of these appear to have suffered any snow or ice damage which isn’t surprising given their overall sturdiness. Of course as more mature sized trees there will be much greater forces on these from any accumulating snow or ice. Like the Cork Oak mentioned earlier, these have branches that are relatively flexible. The larger leaf size of course provided a much large surface area for snow and ice. These coming from interior California they evolved with very different conditions so it is hard to say exactly how well these will do as mature sized trees. The multi-stemmed trees could be problematic later unless one stem comes to dominate and shades out its competitors. It is not unusual for these to have a more brushy juvenile phase.
Garrya x issaquahensis ‘Glasnevin Wine’
I planted this in Fall of 2012 at the top of bank in South Waterfront. It is struggling in part because it is in an area where the public/homeless occasionally walk through to stash their belongings. I planted it here near the north most overlook because it would be very visible for those walking by in the winter to see. Because of this it is still very small and subject to being stepped on or over, though it is slowly gaining girth and, I hope, the vigor to overcome the ‘conditions’ here. For now the ice is the least of its worries. Hopefully, in a couple of more years it will be worth posting a picture of it.
This is such a sad little thing and it should be gorgeous! Arbutus arizonica, stomped and abused. I keep my fingers crossed, that despite its limited top growth, it is able to keep expanding its root system and increase its vigor to eventually triumph.
Arbutus arizonica
As I mentioned before, I love Madrone, and this one from the mountains of southern Arizona, the Madrean Sky Islands, look it up, these are fantastical places, is an exceptional tree. Unfortunately only two remain of the three I planted, the one lost in a horrible irrigation accident, which was fatal. and the other two flattened by homeless and/or ignoramuses, who have seemingly singled them out to sometimes step on, prostrating the trunks and no doubt stressing them severely. It has been five years so I don’t know if they will ever recover. Again, ice and snow are so far not an issue…yet for these…I wish!
Fremontodendron ‘San Gabriel’, on of the taller California Flannel Bushes to 18′ or so and hardy to zn7b. This one gets as wide as tall and is welcome to smother some of its smaller neighbors.
Fremontodendron x ‘San Gabriel’ (F. californicum and F. mexicanum)
I am excited about this plant. It took a good three years to get it established, before it began to put on significant growth. Now standing next to it it is over my head and just visible from the esplanade if you know where to look. Ultimately it will get 15’-20’ tall. As it gains in stature it will be very noticeable when it blooms and it is far enough from the esplanade that it should never require regular pruning to keep it in bounds as pruning these can literally be a very irritating experience. I had some concerns about this plants ability to withstand the ice and snow and it still may become an issue, but it weathered this last winter unscathed.
Ceanothus thrysiflorus ‘Oregon Mist’
Ceanothus thyrsiflorus ‘Oregon Mist’, ‘Skylark’ and ‘Eldorado’
All three of these are nice selections of our native Blue Blossom with very different habits and leaf characteristics. None of these had an issue with the snow or ice on these sites. There are at least a dozen ‘Skylarks’ while I planted only 3 each of the other two. I hear stories of gardeners whose plants toppled or failed and it begs what were the conditions that they were growing under. None of these ever received any supplemental summer water and all three were growing in unamended compacted soils, sometime including rocky fill. Fast vigorous growth for these translates into a short life. I imagine problems would include top heavy growth, out of balance with the roots, and faster growing weaker more prone to failure under load. ‘Oregon Mist’ is a larger growing form with leaves that are small for the species type. ‘Skylark’ tends to stay somewhat smaller and more compact, 6′-7′, reducing the chance for winter failures as discussed here. My only issue with ‘Eldorado’ is that it has begun to throw green reversions, something I haven’t seen before. It also is looking a little gawky because some of the surrounding plants, grasses and deciduous shrubs, have shaded out the lower growth on it which is revealed now in winter. Not so pretty. If you want to maximize strength in these, full sun, no summer water at all, no crowding and by all means no amendments or organic mulch! They need it rough to mimic their natural growing conditions.
Arctostaphylos rudis, a perfectly adequate, xeric west coaster for the right spot.
Arctostaphylos rudis
So far this is an unimpressive plant. I know, maybe not fair. It grows along the top of bank just east of the Garden at South Waterfront. Ultimately a low plant to maybe 2’ tall it is still small and compact with small to medium sized leaves for a Manzanita, these plants have suffered no snow or ice damage. I don’t expect it ever to be a problem. At some point its unique shredded looking bark will become more apparent. A coastal Californian from sandy soils I did have some concerns about it here on this flat portion of bank, but it has adjusted well to the rain despite our getting more than double what it’s used to.
Halimium ocymoides. This is the healthiest remaining planting of these in the Park. The brown is from Zauschneria and Iris that have died down.
Halimium ocymoides
These ‘other rock roses’ are beginning to decline, but mostly because their more vigorous neighbors are encroaching and beginning to crowd them. Low, twiggy, compact ever’gray’ plants with brilliant yellow ‘rose’ flowers, these tend to spring back after the weight of snow and ice retreats.
Arctostaphylos canescens var. sonomensis. Two remain in this spot the others have been overwhelmed by too vigorous neighbors.
Arctostaphylos canescens ssp. Sonomensis
My only error with this plant was to plant it too close to other somewhat faster growing shrubs which have been overwhelming some of them. This same relatively slow growth rate results in a sturdy compact plant. Two of them have formed strong plants that are completely undamaged by this winter’s snow and ice. Like all of the other plants here these have had no supplemental water. One difference is that these two beds, removed from the riverbank, just west of the esplanade, were bulked up a bit with a few inches of pumice and were topped with 1/4-10 gravel in an effort to raise the crowns above the otherwise flat beds that are surrounded by concrete walkways that shed water into them.
[There was contention on this point during the design phase of the wider landscape as it was the LA’s intention to direct as much hard surface runoff into the beds as possible while being planted with choices not particularly adapted to such winter wet soil conditions. I later made the decision to begin bulking and building up several of the most severely effected beds within the Garden area and here.]
Arctostaphylos x ‘Pacific Mist’
This low broad Manzanita, planted in four areas near the marina and restaurant ramps, has been very successful suffering no snow or ice damage. While Manzanitas seem some what brittle, a couple of these were broken a few years ago by people tromping through them, breaking off big pieces from the main stem, overall they are durable. I suspect that because of their structure, they grow in what I would call a somewhat stiff ‘heap’ with many curving branches growing back and forth over themselves, but separate, not quite upright enough to gain the height and stature of many of the taller Manzanita. This seems to give it a more spring like character, the snow and ice, loading it, pushing it straight down, where the lower branches help spread and share the load. The entire plant has a broad base because of this with the ground itself supporting the lowest branches which in turn support the upper structure. I grow this one at home as well where I have to keep nipping it back to keep it out of the sidewalk and street. Such treatment doesn’t seem to compromise its ability to carry a snow load even though it promotes a taller somewhat narrower overall structure.
The damage you see here of this Cistus x dansereuai ‘Jenkyn Place’ is typical of several of the Cistus on these two sites.
Cistus x dansereaui ‘Jenkyn Place’
While I’ve planted these in two somewhat unexpected places, just above the Willamette’s high water mark as delineated by the rocky rip-rap on the bank, one next to the restaurant’s ramp and the other by the ramp to the north breakwater, these plants with their dark, narrow resiny leaves have performed well, at least until now. These grow with many thin upright stems forming a relatively dense dark mass. Up until now this has served these well. This winter has exacted an aesthetic price. While the plants don’t appear to be compromised too much, in terms of their health, these were splayed open and leaned over to a point to which they haven’t been able to stand back up, compromising their uniformity and revealing, in some cases, bare stems. If you look closely there are several branches that split and tore down at attachment points as well. Cistus don’t tend to re-sprout from older wood when cut back hard, I don’t expect new shoots to arise from these now exposed stems, but we shall see! Had these been lightly sheared periodically, tipped back, it would have likely promoted more sturdy growth, but these are ‘secondary’ plants in a large landscape. Time and labor are not available. This response to load is common to several of the other Rock Roses I’ve grown. In their case, as true Mediterraneans, they were more likely to experience periodic fire than they were to heavy wet snow and ice loads and, didn’t develop a sturdier structure.
Carpenteria californica ‘Elizabeth’
I planted several of these scattered near the top of the bank in positions where they would get some protection from the late afternoon sun. Overall, given all of the conditions on these sites, compacted relatively poor soil without irrigation these have done okay. They are much smaller than others I know or planted in the Portland area including the one in my own garden. None are over 5’. None suffered any damage. Mine at home, that I periodically selectively cut back because of its tendency to form a gawky somewhat scraggly appearance, is generally below 8’ tall. While some of its stems bent under the weight, none broke. In general this is a pretty stiff upright grower.
Quercus hypoleucoides, the still immature 12′ or so tall canopy, reminds me more of arcing bamboo culms than an Oak tree.
Quercus hypoluecoides
This evergreen oak’s narrow leaves don’t present a lot of surface for snow and ice to cling to, but, at least as a young tree, it is fairly dense. None of the handful of these here suffered any damage. Their growth rates very widely on this site. The one pictured above has topped 12’ or so with relatively vigorous branching and a dense silhouette. The others have been considerably slower, none of them have attained even half of the faster growing ‘brother’s’ height. These seem to possess the strength and flexibility of most of the other evergreen Oaks I’ve planted along the river here. These are all small juvenile trees, this is far from a definitive look at this group of Oaks. A broader survey of such Oaks in the Portland area is needed.
Arctostaphylos x ‘Sunset’ a proven and durable plant all along the west coast.
Arctostaphylos x (A. pajaroensis and A. hookeri) ‘Sunset’
A tough, durable Manzanita that is more tolerant of supplemental water in its early years, but wean it early any way. Both parents of this hybrid come from a very small area near Monterey Bay. Many species and populations can be found today on only very small properties. They were in decline even before the massive habitat loss that a growing urban population has brought. This plant forms into a compact, fairly dense shrub. The single planting I made here, left of the restaurant’s ramp, has not suffered from the snow and ice at all. This particular planting I didn’t adequately space, I tried to do too much here, and the A. ‘Sunset’ are outgrowing, overwhelming their near neighbors…my bad!
Ceanothus ‘Emily Brown’
Ceanothus gloriosus var. exaltatus ‘Emily Brown’
I’ve planted these in several places at the top of the bank and all are still performing well, in some cases, too well. Some are duking it out with Sunset Manzanita for space. This is one plant that we should have been tipping back both to make it more dense and to limit its spatial desires. The plant in the picture looks a bit messy because of the taller growing Zauschneria ‘Silver Select’ that grows up through it, dying back for the winter, now giving it a rather unkempt appearance. None of these have suffered any damage from ice and snow this winter.
Cistus x pulverulentus ‘Sunset’. I remember having a crew of about a dozen guys here tearing out the original grasses, cutting through the poly netting that was intended to reduce surface erosion, good idea, horrible material to deal with down the road. The ground was summer baked brick hard.
Cistus x pulverulentus ‘Sunset’
There are three double rowed bands of this planted on the bank around the marina. You either like its hot pink flowers or you don’t, I do. This is another low compact rock rose with wooly/felted evergreen leaves somewhat smaller than its typical mature size at about 1 1/2’ tall and maybe 4’+ across. Given that these have suffered through eight winters here I think they look good. A few holes here and there doesn’t detract too much from the overall appearance. I’ve not gardened with these for a longer period anywhere else. Many Mediterraneans tend to be relatively short lived in our climate and soils and can require periodic removal and replacement to maintain the original design intent.
Arctostaphylo pajaroensis ‘Warren Roberts’ with its still fairly tightly held buds.
Arctostaphylos pajaroensis ‘Warren Roberts’
One of my favorite Manzanita, so far, for several reasons. All of the selections are beautiful with their unusual and brightly colored spring growth that follows their floral display. This is the selection I have planted the most beginning with my first planting of it at home more than 15 years ago (It was removed in preparation for a home remodel/expansion.). This one tends to be a little lower and more broad than the other selections of this species, with very sinuous branches giving it a scale that fits into even many relatively small local urban lots. While these can easily be thinned over time to expose more of their beautiful bark, these in the Park have received next to no thinning or pruning. Their growth rate is moderate, producing ‘springy’ growth that came through the ice and snow completely undamaged. This species is limited to a very small area along the central California coast, in the Pajaro River area, mostly west of Salinas, the town of my birth, toward the low hills above the Elkhorn Slough area, not an area known for its snow or Ice. Many of the Manzanita, all of them indigenous to western North America, with the exception of the ground hugging Kinnickinnick, are concentrated in California, a large number of which are limited to the relatively dry hills, dunes and draws of the coast…yet they are proving sturdy here!
Rhamnus alaternus ‘Argenteovariegata’
I only planted one of these here, next to the Harborside Restaurant, midway down the bank. This is obviously a tough site forcing it to grow in compacted fill. Normally a relatively vigorous grower, which is why I planted down the bank as I did, this one is stunted, still under 5’ after seven years, these typically grow 8’-15’ tall. This one suffered no damage at all this winter, nor has the larger and older plant on SE 28th Ave in the Reed College hellstrip. Its stiffly upright habit and small leaves seem to serve it well.
Quercus chrysolepis, the Canyon Live Oak, still small after 8 years, but cute anyway and intact!
Quercus chrysolepis
My Oak comments repeat, I only planted three of these and they are still small, young with mostly juvenile foliage…and they did fine. These three trees have been slower to establish and exhibit top growth than either Q. wislizenii or Q. hypoleucoides nearby. Why??? I don’t know unless it is just their tendency. Still, strong and flexible is the ticket! I suspect that these too would be fine as mature trees as long as their structure is not compromised.
Arctostaphylos viscida ‘Sweet Adinah’
Arctostaphylos viscida ‘Sweet Adinah’
Another gorgeous silver/white leafed Manzanita. This one was replanted in Fall ’12 as it was a temporary campsite for homeless people and the earlier planting was destroyed. This one is just over 2’ tall, probably because of the difficult soil conditions and it has weathered the snow and ice without damage. It is planted just above the rip-rap…(that’s the river reflecting the roofs of structures on the marina docks). These won’t survive inundation, but the last time that happened here was the ‘big flood’ of ’96, a 100 year event. Nothing lives forever and all of these xeric plants do better here than most of the riparian plants have, despite the distance to the river.
Ceanothus impressus ‘Vandenburg’
Normally, grown under good conditions, this is one of my favorite Ceanothus. These, as I discussed in an earlier post, were decimated by previous snows, not because they are a some how inferior selection, but because they were planted too close together and I suspect because of irrigation in their early years that increased their growth rate. Tight spacing of many woody plants will force them into a more exaggerated upright form as they reach for light. These, essentially grew into popsicles on a stick, stretching to light, creating dense masses atop a too long lever. These were specified to be planted on 30” centers because the architects wanted it to fill in quickly!!! This is all too common in big capital projects. The contractor refused to space them more widely when I pressed him. During the 3 year establishment period, which the same contractor oversaw, these received regular irrigation and quickly grew together going vertical. By the time we got maintenance responsibility, the masses of them were impenetrable. I shut down the irrigation across the entire site immediately. A couple years latter, with a significant snowfall, the first plants began toppling. Today only a few remain. Sturdiness is a product of DNA, site conditions, spacing and maintenance. Only DNA is fixed, the others we can effect through our decisions and actions…good or bad.
C. ‘Vandenberg’ is the only xeric planting I review here in the Riverplace section that I did not plant. All of the others were intentionally Fall planted and received no supplemental summer irrigation. Did this stress them, undoubtedly. In my memory none of the relatively few losses of any of these xeric plantings were directly attributable to drought stress, rather, they were from vandalism, intentional or simply indifference, plants repeatedly stomped on or literally pulled out by their roots. I do suspect that some of the herbaceous plantings, not reviewed here, may have been lost to drought during their establishment periods.
Arctostaphylos densiflora ‘Harmony’
Arctostaphylos densiflora ‘Harmony’
A selection of A. densiflora that eventually grows taller than A. d. ‘Howard McMinn’. These were planted in the Fall of ’10 and like the other Arctos on this site are growing relatively slowly. The remaining plants, those not killed by vandalism, are doing well and haven’t suffered damage at all from snow or ice.
Arctostaphylos densiflora ‘Howard McMinn’ leaning a little but still secure and unbroken.
Arctostaphylos densiflora ‘Howard McMinn’
These were planted three years earlier in ’07 just north of the ‘Harmony’ planting at the top of the bank behind some Mahonia aquifolium ‘compacta’. These were quite slow to establish and are still small for ten year old plants. They now seem to be ‘leaning’ down slope some though the roots seem intact and undisturbed. The top growth is quite small in diameter, even wiry and dense. There didn’t seem to be any breakage on first inspection.
Ceanothus cuneatus ‘Blue Sierra’ showing a branch tear.
Ceanothus cuneatus ‘Blue Sierra’
This plant grows in a relatively pronounced herringbone pattern with variously oriented ‘sprays’ of branches, all quite stiff. A few of these were scattered across the site and suffered some, though pretty minimal, damage. The picture shows a branch, sweeping upward, that forks into two similar sized branches, a structure that can be problematic, and in this case, levered one side down resulting in a tear in the supporting main branch below. This is not a ‘fatal’ injury. Within a few years, after pruning away the torn end and cutting back the undamaged half of the branch a bit, barring more damage, the growth habit will likely ‘smooth’ over the injury.
Arctostaphylos bakeri ‘Louis Edmonds’
Arctostaphylos bakeri ‘Louis Edmonds’
A striking plant with its gray/green leaves contrasting with its dark purple bark, these plants are doing well, again growing relatively slowly due to soil conditions. None of these seem to have been bothered by the snow or ice at least those that survived previous vandalism.
Cistus ‘Snowfire’
Cistus x ‘Snowfire’
These have been good performers on this site, at least up until now. When planted in mass, uniformity becomes more of an issue and these were just that. The snow has caused several of them to ‘open up’ leave a few broad holes in them as you look across the planting. While not a fatal injury it is certainly not attractive. As with several of the other Rock Roses an occasional light shearing after flowering will tend to keep these more compact and less likely to suffer this kind of ‘damage’. Cutting earlier will sacrifice the flowers and cutting too deeply into the wood may result in leaving dead stubs visible that won’t re-sprout. Again, we never had the time to do this.
Cistus ‘Elma’
Cistus x cyprius var. ellipticus ‘Elma’
I am conflicted about this plant. I first planted it some 20 years ago on a different site…its still there. That is good. I think my problem has been that I never tipped these back and as a result they get rather rangy. The photo shows branches growing nearly horizontal through itself. This is a very flexible plant, bending greatly, without necessarily breaking. All of this sounds good, but in my case has resulted in plants that are rather messy looking. These ‘need’ pruning, not to protect them so much from snow and ice, but to improve their overall form.
Cistus ladanifer ‘Blanche’
I love the flowers on this Rock Rose, probably my favorite and the foliage too, dark green and resinous with the heavy aromatic scent of labdanum once used to create incense and in perfumes, but the plant itself, at least here in Portland has grown fairly quickly to over 6’ and has suffered in the snow and ice, breaking and tearing many branches down. I also had these begin to lean after previous wet winters when their roots seem to lose their ‘grip’ in the soil. I still like this plant, a lot, but think that it deserves a periodic and judicious pruning to protect its structure and maintain its upright form.
Cistus x platysepalus. The snow did squash this one. The prostrated branches to the side were once upright. The ‘brown’ is leaf fall from the nearby Taxodiums, Bald Cypress.
Cistus x platysepalus
This is another one of my more preferred Rock Roses, I even like the sound of the species name as it comes off my tongue ‘platy-sep-al-us’, for ‘broad sepals’.
[Wonder what all that Latin in those binomials means…if anything? Yes, they exist for more than to confuse us! Take a look at this online botanical dictionary from Caltech!]
The picture shows a very irregular looking plant that suffered beneath the ice and snow…it did. I would still plant this one anyway, though were it in my home garden I would periodically tip it back to keep it more compact, starting from when it was a small plant to make it a little more sturdy. If I were still caring for these I would tip it all back to help it fill back in. I wouldn’t tear these out and I can be kind of ruthless about that.
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All of the shrubs and Oaks I’ve discussed above can be grown here successfully and can even withstand the scattered winters with heavier than normal snow loads and ice like this one, if we pay attention to their structure, their overall form and growth rate. There is no ‘silver bullet’ group of plants that no matter what will perform here year after year…. Well, that’s not really true, but it is a ridiculously short list given the possibilities, because an ignorant or indifferent gardener can ruin almost anything.
Native trees and shrubs, as species, are all ‘adapted’ to ‘their’ own local conditions. As I discussed in the previous post, these conditions include the wider plant communities that these are a part of, and can have a powerful effect on how they grow their, their structure and strength. Native plants will fail in a pristine plant community. They will, overall, survive long enough to reproduce themselves, or neighbors will. Nature has different standards than we do for our landscapes and gardens. Just because there may not be toppling trees and shattered branches in an undisturbed forest when we’re there to see them doesn’t mean that it doesn’t happen. Many of us have unrealistic expectations of the plants that we grow. Sturdy growth must be supported by us the gardeners. In our haste to grow a larger plant we must be aware that we could be setting it up for failure. We must be willing to provide thoughtful selective pruning to encourage a stronger structure, given the conditions that we have here, pinching back new growth here and there, selectively thinning out the denser canopies of certain plants, with holding irrigation, nutrients and amendments for plants unable to limit their growth in the presence of such abundance and learning to tolerate a certain amount of damage, acknowledging that life can be a trial and that perfection is an impossible goal, unless you’re Disneyland (or Washington D.C.), where fantasy trumps reality everyday.
Shrubs have different habits and forms, some, like Oregon Grape are suckering, sending up mostly unbranched vertical shoots, that can be periodically removed to keep them from looking to ungainly, these by the way hold up quite well to our varied winter conditions. While the Asian Mahonia x media group tend to branch heavily up high and, retaining its leaves, presents a huge dense mass for snow and ice to cling to. Many shrubs sprout readily giving the plant its characteristic rounded form, each shoot growing with similar vigor. Whether evergreen or deciduous these share a lot of structural characteristics and can be treated similarly…the difference being that many of the evergreen shrubs in this group may not sprout if they are cut too far back into ‘older’ wood. Other shrubs have a more fountain like form but can become quite gnarly over time if left alone or surprise the gardener with their size which may expand every year. These are often prone to tip layering whenever arching branches come in contact with the soil and can form crowded, congested colonies. And finally, is that group of shrubs that have a more architectural and permanent structure that must be monitored and sometimes limited and directed in order to produce a strong and beautiful structure…that stays within the limits of the garden. Most shrubs are not ‘plant and play’. Depending on your site and growing conditions, they will require your participation if they are to be effective members in your garden’s dance.
Plants, like other life forms, begin to weaken after they reach maturity, their growth rate slows and they approach death. Their care and pruning must acknowledge this. The effective ages of shrubs and trees in the garden can vary from just a few years to many more than one of our lifetimes. Our gardens are artificial, contrivances, but are still communities of living organisms and, as such, we are required to participate in them. When I review the ‘histories’ of the plants above I can begin to see where my/our intervention could have effectively improved a given plant’s performance in the landscape. Sometimes there are practical or logistical reasons for having not done these tasks. Sometimes its ignorance at the time or a misguided hopefulness. But as gardeners we eventually realize that a garden’s success relies on our participation as much as it does on our particular choices when we planted it. A good gardener matures along with his/her garden. We make better choices, improve our practice and recognize when something is beyond our abilities and so scale back and adjust our expectations. Gardening is an ongoing experiment into life. A winters’ storm is just another page in the story for us to learn from.
‘Natural’ landscapes are the result of all of the ‘players’, the plants, the growing conditions, even of the native fauna, each playing their role, fully engaged, in a robust coherent system, each immediately responsive to the next. Quantum physics looks at life as coherent and entangled systems, connected intimately, directly and instantaneously, in a sense, always striving for the ‘betterment’ of the whole, the cell, the tissue, the organ and organism, the wider community. This ‘should’ include us….It does include us, whether we take on the responsibility or not. In our current society our gardens and landscapes are too often separate from most of our lives, incidental, forgotten and too often neglected. We forget that we garden for the garden, care for our landscapes, as much as we may do it for ourselves, it is an obligate and reciprocal relationship…whether we recognize or admit it or not, it is our responsibility, part of our purpose, ultimately, in being here. Both gift and debt. The life in the landscape/garden doesn’t just happen, it is participatory contingent upon our active relationship with it. When our gardens ‘fail’, when our wider landscapes ‘collapse’, in whole or in part, it is likely because of us, our choices and actions. In a sense gardens are always ‘looking’ for proper relationship, we only need to choose to participate.
GardenRiots 