Problems with Municipal Street Tree Code

First off, a slightly late Merry Christmas to all! We hope no one’s grandma got run over by a reindeer this year.

Well with the holidays more or less behind us, I’m certain we must all have our mind on just one thing, which of course is street trees. Is there anything more enchanting than the silhouette of bare winter branches against a dark, rain-soaked sky? Come to think of it, perhaps there is.

I’m going to dive into what I think is wrong with municipal street tree code, and in so doing I’m sure this is going to sound like another one of those really negative posts. Am I just here to pick on municipalities for creating policy on this stuff? If we’re doing things so wrong, then what are my suggestions for positive change? Well, with the publication of this blog post comes my commitment to follow it up with something productive. That may take me a few weeks but we’ll get there.

Let’s start with an example of why I think this is necessary. Coincidentally, Lance Wright recently posted the following commentary, with photos, to Facebook:

“Portland has been planting Parrotia persica frequently as a street tree, probably the cultivar ’Vanessa’. The species is ‘decurrent’, with weak apical dominance, as it has a shrubby form with competing leaders. Often times these tend to sucker and sprout, even without pruning or damage, as does the tree pictured here forming a very congested silhouette down to the ground. These can also be quite broad relative to their height…making them a questionable choice for narrow parking strips such as this. As street trees are rarely pruned /trained this is what you can get. This one has been in place less than five years and is already encroaching into the street and taking over the sidewalk. Some Parrotia are better behaved, but I often see this in SE Portland. I do love these in the right place…I have a 30+ year old one in our garden!”

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Photos by Lance Wright

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So I’m just putting that out there as an example to introduce the topic. It is apparent that something has gone wrong in this instance, because the result is less than desirable. It is worth exploring what that might be.

Rather than Portland, however, my frame of reference here will be the Street Tree Guide for the City of Port Angeles, since it is the city closest to our nursery that has any kind of street tree code. This document is available online here.  (Parrotia is on their list as well! By the way, if any such document exists for Sequim, it is not online that I can find. Let us hope this means it is not too late to craft a more sensible policy!)

I want to begin by saying that I don’t think there is anything wrong with just having guidelines in general that concern street trees. One has to start somewhere, and something is better than nothing. No city, nor its residents, want street trees to rip up sidewalks, drop heavy cones on cars, or otherwise become a public hazard. I can also say this policy is not in any way consistently enforced, as one can tell just by looking around the city. Whether we think a high level of enforcement is good or bad, I would put forth that a city should have the goal of drawing up a plan that allows for easy and consistent enforcement with a minimum of ambiguity or exceptions. That way no one feels like they are being treated unfairly.

Unfortunately, however, a quick look at this document reveals some inconsistencies, which I will describe. One also finds quite a few errors of spelling, word spacing, underlining and layout that make it look a bit sloppy and unprofessional. I’m not saying I’m always perfect in that regard myself, but it jumps out at me. (I’d be glad to fix that!)

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(Click images to enlarge)

I’ll skip over the first page, which I don’t consider to be the most controversial or problematic part of this document. Moving on to the second page, we have a set of guidelines which mostly make good sense and are fine, until we come to the part about minimum caliper requirements. After some consideration I’ve concluded that these requirements are a big part of the problem. Having looked into this topic a bit, I’m wondering if there’s something I’m missing, because the reasons I’ve unearthed so far for establishing minimum caliper requirements just aren’t great. Generally they seem to have more to do with project bids by landscaping firms, rather than individual homeowners: municipalities don’t want landscapers cutting corners on tree size to reduce their costs and appear more competitive. There is also the issue of tree replacement: if a large tree is lost there may be a perceived need to replace it with something immediately substantial. (Even this is debatable, as I hope to demonstrate later.)

The main problem with caliper standards is that they are far too limiting for everyday homeowners or gardeners. The homeowner is going to have a lot more tree options if not restricted to what is available in a large caliper. Also, if they are paying for the trees themselves, this could be the difference between buying a tree vs. not buying it at all, if they are on a tight budget. In my view the homeowner should be automatically exempted from this requirement except perhaps in instances where they are responsible for the loss of a large tree that is being replaced. There are other reasons why cities should be much more open minded about this as well, but I’ll get to that in the follow-up post.

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So here we have the list of recommended large and medium trees for Port Angeles. First of all I notice that at least half of these trees are going to be difficult to find in any size. Suppose we classify trees three different ways: those recommended by municipal tree code of Northwest cities, those available in our local nurseries, and those that are actually the best performers in our region. We would have three very different lists, with some overlap, but a lot less than you might think. This discrepancy is unfortunate but there it is. For example, not once ever in my life have I seen Osage Orange in a nursery around here; it is exceptionally rare in the Northwest.

Then I notice that some of the medium trees grow larger than some of the large trees. So that’s interesting. In general some of the heights seem a bit “off” for what may be expected in our climate. But then others are accurate enough. This leads me to think parts of this list were assembled from a city or cities in a different climate, as some trees grow to a smaller or larger ultimate size in our climate than described by many popular references. A good regionally specific reference as to what ultimate sizes for trees we can truly expect in our climate is found in Trees of Seattle, by Arthur Lee Jacobson (2006). The reader will find some major surprises as to how certain tree species (commonly sold, and otherwise) have performed in the Northwest over time. However, even in that book, some gaps exist for species that haven’t been established in our region for very long.

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I find it interesting that small trees are not preferable. This may be because they don’t cast as much shade or contribute as much canopy for wildlife habitat or sequestration of pollutants. There may be other reasons I haven’t thought of. I think we ought to regard this principle with a great deal of flexibility, as the homeowner may wish to use the space for something besides grass and one huge tree that shades out everything around it.

In general the selection here doesn’t excite me too much. The first thing I would take off the list of small trees is Prunus virginiana. It is ugly and suckers everywhere: I know this because I have been trying to eliminate it from our property for years. I would also note that Acer davidii (never have I seen this in a large caliper, BTW) certainly looks far better in about half shade than in full sun. Ideally a street tree should be adapted to mostly sunny and relatively dry conditions; species should be selected with this in mind.

So taking those lists together, here are the main things that stand out. I know it’s kind of buried down here, but the following issues are really the central point of this post:

1. All the recommended trees are deciduous.

2. The majority of these trees are native to climates where it rains all summer.

So to the first point, although I don’t automatically hate all deciduous trees, I am an advocate of using broad-leaf evergreens far more than we do around here. Some have been accused of looking “gloomy” in our winters, but for the most part I think they add interest by giving you something to look at in winter besides bare sticks. Many of them have interesting foliage, form, or bark that is very appealing when the winter sun hits it. There are literally hundreds of options for broadleaf evergreen trees that do well in the Northwest; many of which you can read about in books such as Trees for All Seasons. Even if you are not a huge fan of broadleaf evergreens, there can be no sensible reason why ALL the trees on the list need to be deciduous.

But I am sure this all comes back to the caliper requirement. Broadleaf evergreens are generally grown in containers, rather than produced in the field, and are thus seldom available in the large caliper desired. Put another way, because they are container-grown rather than field-grown, they are more expensive to produce to get the same size as a comparable deciduous tree, and thus are not produced because of the lack of demand for the more expensive option. Doubtless this is a major reason they have been largely overlooked.

Now to the second issue. I am aware that some planting areas are irrigated (at least until the irrigation system breaks), and there is a certain amount we can get away with as far as using trees native to climates with more rainfall during the growing season. In the follow-up post I will discuss what I believe makes the most sense as far as selecting and planting species that are well adapted to our region. But, taken together, tree species native to China, Japan, and the Eastern United States, all places where it rains all summer, make less sense here than species better adapted to dry summers. As my readers are well aware, we have a dry-summer climate here in the Northwest. Thus, I simply don’t think it makes sense to recommend continued planting of thirsty trees. It makes even less sense when we consider that our summers have been on a warming trend and water resources are likely to be increasingly strained over time.

Still, I’m not drawing too hard of a line: some tree species from wet-summer climates perform adequately here, and examples of them can be seen in cities all over the Northwest. Some perform well in Port Angeles but not Portland, since Portland is that much hotter and drier. Some of them perform well but only on good soil: in less than ideal soil conditions they languish and die. For example, Cercidiphyllum japonicum, a relatively popular/available selection from the list, really needs heavily amended or deep, fertile soil to do well here without irrigation in the long run. One could recommended it for, say, Mount Vernon, a city built on deep, alluvial soil. But for much of the Northwest this species isn’t a great choice.

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Here is where more problems and inconsistencies pop up. But before getting into that I would say there are large parts of this list I certainly agree with. Many of these trees are inappropriate as street trees and ought not to be used, no doubt about it!

“Large Evergreens” – I can see why something like a 200′ tall douglas fir doesn’t make sense as a street tree. Still, I would think you’d want to allow for quite a few exceptions to this rule, especially for those species which develop dome-shaped canopies, have exceptional drought tolerance, and/or remain compact in stature. I can’t believe they forgot to mention Leyland cypress, the scourge of the Northwest. Also I find it interesting that deciduous conifers and true cypresses are not mentioned here; though obviously they are also not on the approved list. There are a few rather large Monterrey cypresses around Port Angeles, which are on the large side for a street tree but make quite a statement!

The next six things on there are certainly problem trees. However, I would question whether Platanus occidentalis is really so much better behaved than P. x acerifolia, which is on the approved list. My impression is that all Platanus have rather aggressive root systems, but perhaps there is some variation.

Then you get to “palm trees.” This is the part that tells me some snippets of this document were pulled from a completely different climate. I would like to know where in the Pacific Northwest anyone has seen palm trees cause the problems this document accuses them of: invasive root systems, damaging sidewalks, weak wood that breaks easily. In California, larger species of palm trees have moderately aggressive root systems but even these don’t have the capacity to crack sidewalks. Palm trees don’t even form a woody root system. Most problems with palms are associated with species that won’t even grow long-term in our climate (Washingtonia and Phoenix species, mainly). These problems include being messy, harboring rodents, dropping huge leaves and sticky fruit at random, and being a major fire hazard when the older leaves aren’t trimmed off. But none of these issues were mentioned in our document, so I’m just saying let’s be honest about what those problems are.

Most importantly, because we cannot grow those problematic species of palms in our climate, all the concerns about them that I described don’t mean much here in the Northwest. Our most popular hardy palm, Trachycarpus fortunei, is quite well behaved, has never been known to harbor rodents, possesses fruits that are small and not messy, and I’m darned if I’ve ever heard of one catching fire.

Now as far as using T. fortunei as a street tree in our climate, I think that it is too small-scale to be impressive, besides which it prefers summer water. There are some nice ones in Port Angeles (including some right along Eunice St. as street trees) but they can also look a bit weather-beaten with exposure. So to clarify, I’m not advocating its use as a street tree; I mainly want this document to make sense from a horticultural standpoint.

(Now Jubaea chilensis as a street tree, I could get behind! The Seattle Arboretum invested in some large ones a few years back, which so far has paid off as they are looking great [except for people stealing the fronds for Palm Sunday]. It has also proven hardy in Victoria. Notably, this species is native to a summer-dry climate. Of course, one may still complain about the fact that it may take decades for enough clear trunk to be produced that the fronds are above head height.)

So moving on from palm trees, I have no problems with the next bit, although I will say I have noticed quite a few of these being used as street trees in Port Angeles. I find it interesting that Fraxinus are prohibited generally; certain ash cultivars have been very popular street trees in other municipalities, especially in the interior West, and remain so even now with new plantings continuing. Three specific ashes are mentioned and it’s ambiguous as to whether the widely used types should be allowed. Also, as long as we’re considering birch, we may as well ban them all equally since they are all aggressive surface rooters that are greedy for water and can get significant pest problems when they get too dry (though I’ve seen less of this in Clallam County than in, say, Seattle or Olympia, no doubt because summers are cooler).

Moving on to horsechestnut—wait, didn’t we just see that on the recommended trees list? And it’s certainly more LARGE than medium. Also it reseeds itself. It does great here and is very well adapted, but if we are concerned about reseeding potential, we probably don’t want to recommend it.

Fruit bearing trees—mixed feelings here, since there is something to be said for planting fruit trees in publicly accessible places. However the problems with them are substantial: dropping fruit on cars, staining sidewalks, etc. There would need to be some assurance that they will be pruned annually and maintained to fit the space. I don’t expect that to be realistic in most instances.

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Overplanted trees: YES! I’m on board with not using any more of these. But let’s add to the list virtually anything else native to a climate with wet summers that is reasonably common—perhaps granting exceptions for a few tough species that still do pretty well here (eastern US oaks, for example). As long as we’re telling people what not to plant, we might as well be consistent!

Ok, that is enough with the critical mindset for now. In a future installment, I promise to offer constructive thoughts on the topic in general, on what types of trees should be used, and will be so bold as to recommend at least a starter selection of appropriate species that would make great street trees in the Northwest.

The Amazing Resilience of Trees

Happy New Year! It has been a while, but since I did a general business update last time, I think I will talk about something else today. There is not much exciting to report about December’s big freeze, as we weathered it without much damage; unless you call the major expense of heating three large greenhouses for a week “damage” which I just may. (Did I mention that this is a great time to order more plants?)

Of all the blog posts I have written here, the one that continues to get the most hits is this post about how to prune your leyland cypress. At the risk of stating the obvious, this tells me that a lot of folks are searching the internet for useful information about how to prune them. And they may be disappointed to find that I basically say not to bother planting them to start with if they are going to need pruning constantly. But I’ll stick by that statement because it still makes plenty of sense if you stop to think about it. Perhaps it also tells me that way too many people are planting leyland cypress.

But if you’re determined to keep your leyland, and really want to know how to prune it; well, I’ll tell you. You’re best off shearing them annually at minimum, preferably right before new growth starts in spring; and it’s best if you don’t cut into old wood. You don’t have to shear; individual pruning cuts will also work, but doing it that way may take longer, depending on your methods, equipment and the height of your plant(s). That is about all there is to it, I think.

I wanted to revisit those trees at Independent Bible Church because of a dire prediction I made; which was basically that, since someone cut way too much green material off of them, they would mostly be dead or in otherwise sorry shape by now. Well fortunately I am not always right about everything, and in this case the trees have proven exceptionally resilient. Mind you they have a lot going for them: they are in the perfect climate and they are on an irrigation system. I have to admit some of these trees actually look great and are now making a shapely screen just like they are supposed to. I took these pictures in September.

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Now some of the ones that were really chopped up still look ratty and probably always will. Because for most conifers, including these, you still can’t cut into old huge limbs and expect new growth to come out. The remarkable thing though is that none of these trees has actually died (except, of course, for the ones they removed entirely). Some of them probably lost 90% of their foliage but are still hanging on and trying to grow out of it. I have to admit I didn’t expect that.

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So there you go. No matter how much abuse trees are subjected to, they still do everything they can hang on. Aren’t trees amazing?

While we’re on the subject, I thought I’d revisit the trees at Carrie Blake Park, which I rather ungraciously dubbed as “hell for plants” in this blog post a couple years ago. I think I had good reason to be irked at the time, but things are looking much better there now.

If this is of interest to you, you may wish to go back and read the post I am referencing before going on. If I were really ambitious it would be nice to produce a side-by-side before and after comparison, but I did not always take the same pictures of the same trees, and certainly not from the same angle. Let’s go through some pictures I took last August.

Remember those sad garry oaks that had way too many of their lower branches pruned off of them? They actually look pretty nice now, for the most part.

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You can see where some of them did some serious resprouting along the trunk where branches had been removed.

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In some cases this was pruned off yet again, but at least they didn’t limb the trees up any farther. Also the maintenance folk seem to have missed a few of them. (Captions are below the photos from here on out.)

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Remember the oak that was pruned to just two branches? Here it is now, hanging on and looking better.

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The amur maples generally look pretty good; it seems they ought to be fine.

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The European birch, mysteriously enough, continues to hang on; and doesn’t look half bad.

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Here’s what became of that arborvitae hedge. It’s hard not to feel bad for whoever paid for all those arborvitaes. At least the ones that survived look decent now.

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I guess this thing is our native Ribes sanguineum. Eek. Perhaps not a total failure, but this doesn’t exactly get one excited about the beauty of native plants. There are better choices.

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Arctostaphylos x media, actually well adapted to the site, continues to flourish.

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Vaccinium ovatum continues to look about as dead as it always has. Sorry, I think it’s a bit too late for fresh mulch (and anyway bark isn’t the best).

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Likewise, kinnikkinnik continues to have problems at this site (though there is a decent patch or two, such as around the Vaccinium pictured above). OK, someone can remove this now.

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This site really has a lot of potential. Maybe I’ll have the chance to be involved here sometime.

This may (or may not – ha) lead me to a future blog post about the challenges municipalities face maintaining such landscapes or gardens, and a possible solution.

I’ll also provide an update on the low-impact garden at Carrie Blake Park this summer. I really doubt Agave ‘Blue Glow’ endured the drop to the upper teens that we had last December, but I haven’t gotten out there to check on it yet.

Dryland Plant Management in the Nursery and Landscape

So, to follow up on a recent post, we hear that the proposed Seattle green code provisions have been shelved for now. Apparently they are going start over next year and consult various horticulture/landscaping industry representatives this time to draft a provision that makes sense. I have mixed feelings. Partly I almost think it would be (dare I say) funny to see the rule go forward more or less as originally proposed, just to see how nurseries and people would respond. Imagine Swanson’s selling 75% native plants… heh heh heh. Anyway, I read that there is going to be some big meeting about it on September 5th. I am really bummed that I did not get invitated, especially since all the ideas I sent them were so well-received by my readers (including many who didn’t comment on my blog). But I’m actually not that bummed, since we have a lot of things to do out here that are funner than sitting in meetings; and Seattle is far away, with lots of traffic, and politics, and people who sit in meetings. At least that is our perspective from the far away land of Sequim.

I wrote (more or less) against the rule, but (in part) not for the same reasons other people wrote against it. I really like this post about it by Mark Turner, a respected authority about native plants, who presents a very well-thought out and balanced view. On the other hand, I note that many of these letters make two major points which I believe are false: one, that native plants pose special problems when it comes to producing them in the nursery and/or growing them in your garden; two, that native plants offer such a limited selection as to be uninteresting or unexciting. I can see what people who make such comments are getting at, but ultimately I don’t buy either of these points as valuable refutations of the green code provisions as originally proposed. For me this whole issue really comes down to water use: that should be the central focus in crafting this provision. So in this post I shall attempt to demonstrate that nursery plants are not really that difficult to produce or cultivate. In a future post I may attempt to expand upon point number two.

In my letter to the Seattle City Council, I stated that “native and water-wise plants are, broadly speaking, not difficult to grow either in nurseries or gardens.” This is likely a somewhat controversial statement, since its runs contrary to what most other people writing letters to the Seattle City Council on this topic (at least, the ones I got to see) seem to think about growing our native plants. So while not everyone may agree with me, I still consider this to be a matter of education and adjusting to different practices from what nurseries and gardeners are usually accustomed to. For that reason I am happy to divulge some of our methods when it comes to successfully producing and maintaining these plants. Perhaps over the winter I will have time to revise and expand this into more of a formal article and put it on the Desert Northwest web site.

Dryland Plants in the Nursery

Some think that dryland and/or native plants are unamenable to nursery production and therefore will never become popular. Our starting assumption, then, is that there is nothing wrong with the plants, since they are obviously well adapted here, being native; so there must be something wrong with conventional nursery production. And, based on our experience, we find that the main thing that can go wrong with these plants is supplying too much water, especially in the summer. Most growers have their plants on a sprinkler system that is timed to water at regular intervals. Frequently the sprinklers are set to run for a couple hours every day (overnight, ideally) during the growing season. A few smaller growers hand-water everything and can use that method to regulate how much water plants get. It should come as no surprise that we do not believe one should indiscriminately water the crap out of everything in a climate that has a pronounced very dry season occurring reliably every summer.

So we don’t want to soak our plants to death with timed waterings, but we sure as heck don’t have time to hand-water it all either. So we have decided to say “no” to timers and “yes” to sprinklers. Using sprinklers, we water more or less often depending on what the plants need to maintain good growth, and on the weather. What this looks like is during a typical summer heat wave, the plants get water perhaps every 36 hours or so. During periods of cooler weather watering goes to a 60 – 72 hour schedule. We think it best to give the plants a very thorough soaking when watering, and then let the plants dry out somewhat between waterings. We just wait until they really need it before we turn the sprinkler on. (As an aside, some nursery people are afraid to thoroughly soak plants when watering, because they may get too wet and start to rot. We believe this is only a problem if your soil mix is too heavy, or if you are not letting the plants go dry enough between waterings.)

In conventional nursery production, the problem of keeping plants watered is frequently aggravated by over-fertilization. Potted nursery stock that is given the maximum amount of fertilizer it can handle without burning frequently develops an excess of top growth that is not able to be sustained by the amount of roots in the pot. Such plants also get very rootbound which is not ideal. Sometimes retail nurseries find themselves having to water such plants twice a day to keep them from drying, which is always a hassle. Additionally, once these plants are set in the ground it takes a couple years for them to develop a large enough root system to sustain the top growth. Although such plants will frequently come out just fine in the end with proper care, we don’t think this is the ideal way to grow plants.

Our method is to give plants basically as little fertilizer as we can get away with without compromising quality. Also, we use only organic fertilizers. Sometimes our plants may not look quite as full as conventionally grown stock (but then again, sometimes they do!) but we know that it is important to have a plant with a strong and healthy root system so the plant will experience little or no setback when transplanted to the ground. However – and here it might sound like I’m totally contradicting myself – “as little fertilizer as we can get away with” is often more than might be expected for certain plants. For example, we find that Ceanothus and Arctostaphylos are pretty heavy feeders in general, and sometimes surprisingly so, despite their preference for harsh sites in the wild. Really clever soils people could probably explain this, but all I can say is “go figure.” (Well, now that I think about it, there might be some connection with their adaptability to fire ecology.)

Some people – and we went through this phase for a while there – think dryland plants need extra gritty soil for the super good drainage they need to survive in containers. This, we think, is sometimes a little bit true, but mostly not really. As long as you are not watering too frequently – and that’s the important part – most dryland plants will grow just fine in an ordinary, reasonably well-drained commercial potting mix. This is even true of seriously deserty plants like sagebrush. A bark-based mix with some pumice is ideal, and a little compost won’t hurt anything either. It’s true that certain plants require extra grit, but these tend to be in the minority (unless you are specializing in alpines, in which case you probably already know what you are doing and don’t need to read this). Beyond “alpine” it is difficult to generalize about which plants these are: usually just a few species per large genus. Cacti and succulents are a mixed bag; many of these do require gritty soil, but a surprising number of hardier types really don’t care what you put them in and may even respond to a richer mix by putting on vigorous growth; bearing in mind the aforementioned caveats about watering.

Finally, since we have dry summers, a lot of our native plants are adapted to stop growing in the summer. We find that they are better not messed with in summer. Potting up, planting out, anything that involves messing with roots should be done in spring if possible; the second choice would be fall. Of course they’re not doing much in winter either, and wet/rot can be an issue when transplanting at that time, though many species don’t mind.

Dryland Plants in the Garden/Landscape

Water-wise plants, including our dryland natives, may fail in the landscape for numerous reasons, but I think the most frequent are too much water, not enough water, and inadequate soil preparation. There are definitely some misconceptions that need to be addressed in this area. For one thing, dryland plants are (for the most part… most succulents excepted) not so tough that you can just plunk them out in a harsh, awful site with terrible soil and not water them at all. Why not, you ask? They’re native. Well, when something seeds itself in the wild, the first thing it does is send a taproot straight down into the subsoil as fast as possible so it won’t dry up in its first summer. The same species planted out of a container doesn’t have this advantage (especially if the soil has been compacted or scraped off), so it will need a little help to get established.


Time sequence of container-grown plant vs. self-seeded plant.

In actuality, native plants, generally, will appreciate much of the same treatment that is usually provided for “normal”/”conventional” (whatever) plants: they respond as well as any plant to soil amendment and mulch. The main thing one must do differently is watering.

But let’s back up for just a moment and address soil amendment. This does not have to be complicated. Some swear by double digging, but we are of the opinion that this is generally unnecessary. Usually a healthy top-dressing of compost, left on the surface to decompose over time, does the trick. If you want to use less compost, even a little circle of it around each plant, several inches deep, goes a long way towards successful plant establishment. The only time we might not think soil amendment so important for dryland plants is if you actually have existing native topsoil at your planting site. Unless your house is really old, this is probably not you. Usually the native topsoil is scraped off and/or compacted beyond usefulness during new construction.

So, having amended the soil and mulched – and mulch an be a lot of things, including wood chips and rock; but not beauty bark, which is evil because it does not promote healthy soil – the big question is how to water. It probably goes without saying that dryland plants will not grow in a swamp, so we will assume average to well-drained soil here, though a surprising number of these plants will be fine on heavy clay as long as it dries out for a couple months in summer. The best way to water is with the watering basin method. You want to finish your planting hole with a nice, big, deep watering basin so that when you go to water you can fill the hole up all the way, and the water will work its way straight down into the soil. This will encourage deep rooting, as opposed to the shallow rooting that often takes place under conventional irrigation that only sprinkles the soil surface. How often you will want to do this depends on your soil, and how established your plants are; but generally you will want to do this as infrequently as you can get away with before your plants start to wilt, which may be anywhere from about once per week to once per month during the dry season. So we see it is not really a major time-consumer, because you are not out there all the time watering things by hand daily: you just have to pay attention. You’d better believe those new little plants are sending roots straight down as quickly as they can during this process.


Plant root development under various watering techniques, redrawn from The Dry Gardening Handbook by Olivier Filippi.

Conventional methods, by contrast, suppose that once you have installed your irrigation system and set the timer, you can pretty much forget about things. This mentality leads to the failure of native plantings that end up getting too wet. It is motivated by the short-term convenience of not having to pay attention to the planting and hand-water until the plants become established. If we consider how much it costs to install and maintain an irrigation system (they always break, of course), and the cost of all the water that is used, perhaps we can say it is time to re-educate people about more practical ways to create sustainable plantings and gardens. A little more care in the first year or two after planting goes a long way towards sustainability of a water-wise landscape.

And that is where I shall leave it for now. I hope that has been helpful, or at least interesting.

On a completely different note: you still have one more day to come and visit us at our September Open House! Don’t worry, we haven’t sold out of awesome plants yet. Come and see us if you can!

Carrie Blake Park, Sequim: Hell for plants?

I think I may have discovered the place of eternal torment and damnation for ill-fated plants, and it’s right here in Sequim, at the popular Carrie Blake Park. I go there with my family quite a bit to walk around and enjoy the wildlife, and so my son can play on the toys. One part of the walk is planted with native plants, and looks like this:

Looks like it has potential, right? The native plants section is planted with perhaps 15 species, some of which will be pictured below.

One of our most special native plants is Garry oak (Quercus garryana) – although common in Oregon, it is quite rare this far north. Here in Sequim we have the remnants of an outlying oak prairie, which we would think is rather special except that most of it has been destroyed as a result of urbanization or agricultural practices. Here’s one that’s managed to survive being urbanizated; in fact they cared about it enough to route Hendrickson Road around it:

As you can see they are stately large trees, looking as much like a western oak as any of the California species, yet specially adapted to the Northwest in drier areas. And because they are quite slow growing and lack bright fall colors, they have not really caught on as a popular shade tree for gardens.

So, getting back to the park, there are a number of these planted along the trail pictured above, and near the north entrance to the park. In my visits I had been enjoying watching them develop and slowly assuming their typical rugged shape. So imagine my shock one day when I was walking along the path and saw this:

That’s right, you’re looking at a Garry oak that was once full and beautiful, with almost all of its branches pruned off. But wait! It doesn’t end there:

I’m sure this one (above) was pruned slightly less severely only because some of the higher branches were out of reach.

A row of three Garry oak sticks (above). If this is a bit difficult to make out it’s because, well, there’s not much left to look at.

Here we’ve managed to prune off every last one of the side branches while retaining the forked leader – brilliant.

Sometimes Garry oaks grow with multiple trunks, so it’s great that the natural form of this specimen has been, shall we say, emphasized.

Welcome to stumpytown, ye sad little trees.

The mad pruner strikes again!

Even Oregon ash is not immune to this treatment.

The funny thing is this pruning tactic is not achieving its desired end, which I can only suppose is to direct growth to the top of the tree. These trees are fighting to live by sprouting branches all along the trunk. These goofy looking sticks are about to look even goofier, like columnar little oak pom-poms, or something like that.

Let’s take a look at the other side of this path. Overall this seems like someone’s well-intentioned concept was poorly executed. This site appears to have heavily compacted, poor soil. I’m guessing this was planted with the usual “native plants require no care” mentality which really isn’t as true as most people think.

Here (above) is one of several flame maples (Acer ginnala) that is obviously under stress – note the numerous shoots arising from the base, and dead branches. I may be wrong, but if I had to guess I’d say the soil was probably not amended when this was planted. This is a challenge for balled and burlapped trees, even native species. Think about it: if a tree has half its roots cut off when harvested from its site of production, wouldn’t it need to be babied along a little bit at planting time? Of course, there may be something else going on here as well; I didn’t look closely at it.

Kinnikkinnik (Arctostaphylos uva-ursi) was heavily used here, but did not look good with extensive dead patches. I have to wonder if these plants were from a natively sourced kinnikkinnik, or a cultivar such as ‘Massachusetts’ which is poorly suited to our dry summers. Again I don’t claim to have the answer but my suspicions are aroused.

Evergreen huckleberry (Vaccinium ovatum) is a great plant but it hates compacted soils. This was one of the better ones – many were stone dead (could someone have thought to remove dead plants from the planting before taking the time to slice and dice oak trees? Anyway…). Actually, a lot of our native plants will handle dry soils, but not compacted, dry soils. Additionally, when many native plants seed themselves in nature, they have the advantage of being able to quickly put down a very long taproot from an early age to ensure a constant moisture supply from the subsoil, an option not available to containerized plants that are planted out with branching root systems. In the background you can see some rather stumpy looking Mahonias which are making it but not really thriving. This planting illustrates very well that even native plants are not 100% tough and care free, and sometimes need a little help.

And then we have this random European birch (Betula pendula) tree. Why? I don’t know. It’s neither native nor drought tolerant. Actually, I think birches are among the worst possible choices for dry-summer Northwest gardens, and vastly overused here in general. Yeah, I know we have a native one, but even it still isn’t appropriate for dry sites like this. (Looking closely you can also see two more dead evergreen huckleberry plants in this picture.)

One plant that has actually performed well in this setting is this excellent form of our native Arctostaphylos x media, which combines flower and leaf appearance, vigor, and adaptability as well as I have ever seen with this hybrid.

In other parts of the park, one wonders if caretakers have heard of the term mulch. If you’re a balled an burlapped tree with half your roots cut off, imagine trying to get established competing against this much grass, and with no summer water.

Here’s the top of the tree – not looking good.

Again, an investment has been made but is not being well cared for.

This tree on close examination was obviously planted at least a few inches too deeply. It’s really a waste of money and effort to just plunk things into the ground without proper planting knowledge for things to survive and grow.

You can see that the base of the trunk was covered right up. One little branch of this poor tree is still trying to live!

This tree is certainly alive, and doesn’t look half bad on top, but has obviously been a repeat victim of “weedwhacker blight.”

On the same tree we have this really splendid pruning cut.

To line the south entrance to the park, purple leaf plums have been chosen. Unfortunately, their visual impact suffers from the fact that you can about see right through them.

Purple leaf plums are among my least favorite trees (though, I acknowledge, some cultivars are worse than others). In general, they only do something interesting for about a week and a half in spring when they are in bloom, and then look ugly the whole rest of the year. They have poor form and many of them seem to be pest and disease magnets.

And three random cherry trees. I’m not sure why. At least they look better than the plums.

Many of the flowering cherry trees in the park are in poor health, though. For example, Mr. Mad Pruners might have expended a little effort on this one, like, right at the base.

Another example of great design, poor planting choice – this worthless Nandina ‘Plum Passion’. This is one of many plants that has obviously been developed for impulse appeal at the nursery rather than long term performance in the landscape (the subject of a future blog post!).

The lack of upkeep in this meditation garden would probably not make Sequim’s sister city in Japan proud. The only thing to meditate about is how long it would take to pull all those weeds out of it.

This extensive planting is almost well done if a bit too orderly and unnatural for my taste.

As you can see, Monsanto-manufactured RoundUp remains the weed control method of choice. Although I suppose things would be worse if they just let everything go.

In places this planting perhaps seems to have some potential. But perhaps it wouldn’t hurt to note that Euphorbia myrsinites, which reseeds itself freely in Sequim, is a Class B noxious weed in Washington State.

This is new. I’d call this really a colossal waste. Any of these that manage to survive the summer will be eaten by deer this winter. Even from a design standpoint, this would still bother me if better plants were chosen. No further comment.

Nearby is posted this sign showing plans for a large undeveloped area. Click to enlarge.

A close up of the garden plan (click to enlarge). Not to be rude or anything but to me this looks like the confused, uninspired bastard child of a bunch of people’s competing interests. (But then that is pretty much how the City of Sequim functions in general, as far as I can tell from reading the paper.) The space allocated for each concept/section is insufficient to effectively demonstrate any of them well. And why reduce “drought tolerant” to one small area? Why not have the whole thing be drought tolerant – or at least most of it? Perhaps more importantly, shouldn’t the whole thing be deer proof? Who’s going to stand guard to protect all the other plantings from voracious naughty Bambis?

Well I’ve probably gone on long enough about that. Now to some positive news. First, it should be noted that not all of the trees and plantings in the park are dead, ugly, or abused. A proportion of them, even including some newer trees, are healthy and look great.

Also, I really like this:

Under each of those little cages grows, we hope, a little Garry oak (the cages must be to protect them from loppers-wielding Sequim city maintenance workers). You can also see more of the remnant of the Sequim Prairie oaks on the hillside behind them. I’m curious to know whether the restoration area was in fact previously oak prairie, as the soil there appears to be more moist than they usually prefer. The grasses there look nothing like the dry bunchgrasses of a true oak prairie – it’s going to take a lot more work to restore this area fully if indeed that is the goal of those behind this project. One other thing that would be nice to know is whether these oaks were in fact sourced from Sequim Garry oak populations, or brought up from Oregon, which would be less ideal. (The Northwest oak prairie, by the way, is not an entirely natural construct: they have largely persisted from the Holocene warm period (c. 5,000 – 9,000 years ago) when our climate was warmer and drier, by the repeated controlled burning practiced by Native Americans who used the Camas that grew on these prairies. Left to itself this ecosystem would have been out-competed by native conifers long ago.)

My take: the city of Sequim needs to hire someone with true qualifications in horticulture including at least an associates degree in horticulture and CPH (certified professional horticulturist) status, and preferably some formal training in botany so that person will actually have a clue how plants grow. (I have no idea who is responsible for this – perhaps someone was just doing as they were instructed by someone higher up – but if they ever studied horticulture I can’t recommend their place of study!) With a major overhaul in the management of Carrie Blake Park including knowledgeable caretakers, and a lot of luck, perhaps what looks like a plant hell now will someday prove only to be plant purgatory.

How to prune your Tam Juniper

The picture pretty much says it all.

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Pardon the blurry picture.  I’m not sure why that happened.  Our new place in Sequim came with many plants that will not be part of our final design for the garden.  We’ll certainly have a few other Junipers – especially those native to the West – but we have other plans for this spot near the entry to our residence.

Death of a Eucalyptus

Last night another in a series of ferocious windstorms to hit the Northwest this fall/winter swept through my garden. I’m not sure just how hard it blew, but it had to be at least in excess of the 52 mph gust recorded at Shelton before it stopped reporting. I’m amazed the power is still on. The skies opened up blasting rain and wind for about 20 minutes, and the windows shook. The wind was so powerful that it blew a waterfall of rainwater off the roof, bypassing the gutters. After it died down a bit, I went outside on the suspicion that my large E. viminalis, already leaning from the last windstorm, had come down. Indeed I was correct: the surprise was, though it had been leaning strongly to the north from the previous storm, the west winds last night were so strong they picked the tree up and made it fall to the east!

Well, that’s too bad. It was my largest eucalyptus, and measured about 64′ tall. (I have one still standing that is a little taller but not as massive.) It was a very beautiful tree with a nice weeping habit. All the seed capsules on it are unripe – I think it may grow back from the base, but who knows how long it will be before it can produce seeds again. I really wanted some seed from this tree as it is a beautiful form of E. viminalis.

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I planted this tree in June 1999 as a 1′ tall seedling. Here is the last picture I have of it still standing up, in August 2006. It had a beautiful weeping habit and white bark. (Ah, summer…. that sun sure looks nice right about now, doesn’t it?)

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After the infamous December 14th windstorm, our most powerful in 14 years, this tree developed a precarious northerly lean. Closer inspection revealed some damage to the base of the tree where the wood split. Uh oh, thought I. Since it isn’t close to any structures, I didn’t do anything about it.

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Finally, here it is after last night’s storm…. not lying down pointing north, but pointing east. The force of the wind to lift this tree and make it fall the other way must have been incredible! Fortunately, it narrowly missed knocking over a number of other large eucs, though it did break a couple large branches off some. Podocarpus macrophyllus is smashed, but it should stand up again with a little help.

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A close up of the base reveals the problem: root rot that didn’t heal up properly. And I know what caused it. When I planted this tree I buried it too deeply, about 3″ below the soil surface. Then it had some problems in its second winter: the wind knocked it over, but I stood it back up, and it seemed to be OK after that. Now I can see that it never really recovered from this: there is a huge scar where there should be roots to anchor the tree.

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These two large E. dalrympleana also came down in the December 14th windstorm. I was disappointed to find that they, like the E. viminalis, were loaded with unripe seed capsules. If only the wind could have waited another year! However, it should be noted that these two eucs also had root problems. Because they were planted close to a structure, and planted too deep, their root systems developed unevenly.

In fact, all the eucs that have fallen over had some kind of problem with the root system – either they were planted too deep, too close to something, or on soil that was too wet. I still contend that eucalypts planted properly and in an appropriate site are very wind tolerant and present no hazard to anything nearby. But as you can see, a lot can go wrong – plant with caution! I no longer suggest planting the trees deeper than they were in the pot, unless your garden is on pure sand.

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Here’s a tree that’s not so wind tolerant: Acacia dealbata var. subalpina. This one, my largest specimen at 44′ tall, blew down on December 12, before the big windstorm even hit.  It didn’t have any visible root rot problem; the wind heaved it completely out of the ground.  They are beautiful trees, but should be used in wind sheltered gardens only. Thankfully, I have a couple more of these in my garden still standing, and I really hope they will produce some seeds.