Kanzan/Kwanzan cherry tree and pollarding

This is a question which may not belong in this forum, but if not perhaps it will be moved to another forum and I hope will be notified of that --

We in our townhouse strata have several Kanzan or Kwanzan cherry trees, not sure of the correct spelling, which have grown 'way too tall, especially the one in my front patch, where I am attempting to create a "Japanese" garden, ultimately.

The trees are healthy when they aren't eaten by caterpillars in the early summer [this winter we have tanglefooted it]. The question before us is whether or not to pollard them. They were planted perhaps in 1985-86, so are up there in years. They are too large for their location, both roots-wise and height-wise [as high as the top story of the townhouse, almost] for a number of strata owners. I think mine has reached too high owing to compensating for some shade from the building and adjoining tall evergreens protecting it from morning sun -- it gets only afternoon sun from 1:30 pm onward, in summer. The landscaper has pruned it a bit but was reluctant to prune just to produce sprouts all over it.

Our landscaper, who has taken courses etc. and is interested in trees and plants, is suggesting pollarding one as a test, such as mine, then selecting future sprouts for lower branches, for the residents to see. Do the experts here and/or at UBC Botanical Garden think that this tree is too old for pollarding and that it might be killed? It is very vigorous, and sprouts from the base quite frequently. If it is a possibility to pollard it, how low should it be pollarded? The landscaper is suggesting not pollarding too low -- from my impression of web-based reading this is probably a good idea.

Could I have some opinions asap as we will be meeting with the landscaper in a few days...

 

Japanese cherry trees are spoiled by heavy pruning. Successful pollarding is mostly limited to a few kinds of very vigorous large-growing trees such as planes and catalpa trees that are able to produce a satisfactory result. Even then a stump with a hair-like growth of sprouts coming out of the top is not everyone's cup of tea.

If the cherry trees in their existing size (and the height they will continue to add over the years) just aren't acceptable in their current locations then they should be removed and replaced with something smaller-growing.

 

I am aware of this and we have restrained ourselves in pruning them. However, it is going to be "remove" or "prune", I think, from the owners... Some find them very shaggy and messy... realistically, I don't think they will in the end want to remove the roots and replant, for cost reasons, what with all the problems in the pension funds etc. right now... and most of us don't want them just cut down and the stumps left, with no replanting. I am aware of what pollarding produces, but perhaps I can integrate it into something semi-oriental in appearance. It may not, shall we say, be "Japanese" but may look more European, or French, anyway... I have seen pollarded trees in Paris, and once they regrow to some degree and are then re-pruned to select the stronger new growth, they don't look too bad. I am just wondering about killing the tree. I agree, they would be better left alone but they just aren't in the right spot for that, they should never have been planted where they are.

 

I've seen pollarded 'Kanzan' trees, and they look awful. Not a good idea!

"not sure of the correct spelling" - it's 'Kanzan'

 

Oh, heck. Both Ron and Michael F. are not encouraging re pollarding Kanzan cherries. However, I have amassed a vast collection of pollarded tree photos from the Web and from books too, to show my fellow condominium-residents what they will look like. I may go with just experimenting with mine, rather than have enraged neighbours blaming me. The thing is, we have to make some decisions one way or another and several of us think just cutting them down is a mistake, owing to the shade they do give some of us facing the West all summer from the sun in the West, and they do have their decorative features in spring!

I do have one question re "pollarding" -- does the subsequent pruning go right back to the original pollarding-point, or can one prune higher up later from the first pollarding-point and also thin out the unwanted sprouts, thus developing some thickness and a bit of further length in the previously-pollarded branch? This is a question from desperation, really, as the trees in several cases are getting 'way too big and getting into the eavestroughs, etc. Can one also do a combination of pruning and pollarding, i.e. taking out some branches entirely per the pruning books, where they branch off another branch, yet pollarding other branches? Thus keeping the tree much smaller. I know the trunks will look large and the lower branch areas look large... The cluster of townhouses with these trees [not all have them] will perhaps have a "European", if not "Japanese" air... and several of the same or similar cherries in this group never did grow so large as others [perhaps the root zones are more restricted by rock fill or something] and are a perfect shape, really, and seemed to take to a bit of end-branch pruning without any ill effect. My pruning reading seems to imply that end-branch pruning kills branches, but how can one pollard if that is the case? Perhaps it depends on where one cuts, near a node or not...

More responses, or repeat responses, please!

 

Janet, I would have liked to be "not encouraging" too, as I've heard several comments about how unwise it is to prune cherry trees, but I didn't know much about the topic. However, I was just given an article on pollarding (written by Cass Turnbull, of Plant Amnesty in Seattle), and from what it says, it sounds like you're talking about topping the trees. On Plant Amnesty's website, topping is listed as point number 5 of "6 ways to kill your tree":
DO NOT TOP YOUR TREE OR MAKE REPEATED HEADING CUTS (CUT BRANCH TIPS).

Besides killing the tree, topping or cutting branch tips doesn't even work to keep it small. Ironically, it has the opposite effect: it causes rapid and unruly regrowth which is not only ugly, but significantly weaker than the original limbs.
​

In the article, she describes criteria for proper pollarding, including use of a correct species (cherry is definitely not one, as it's prone to water sprouts), all cuts being under 1" in diameter (the tree should be no older than 15 years), development of the pollard heads, and sprouts removed every year for ever after. It's described as being very high maintenance, a style developed when serf labour was cheap; the young trees have to be trained into the pollard shape and the water sprouts must be removed every year.

It sounds like if you prune higher up from the main pollarding point, it could be dangerous, though it's not clear to me whether the danger is just that the tree dies or if it's that the branch falls on someone.

I can't see you winning on this - if you were able to properly pollard the trees and they live, they'll be so expensive to maintain that your strata council will not be pleased anyway.

 

Thank you, wcutler. I own the book by Cass Turnbull on pruning, and puzzled over this many a time especially since our landscape gardener for the the strata townhouse complex we live in wanted to pollard a few of the Kanzan cherries. Since there are many, we gave him permission to do 3 smaller ones which grow at the back of the complex hidden more or less from public view and only seen at the back of several units -- and those owners are tired of the trees and would not mind of they did expire -- they have overgrown their welcome for many owners, why I am not sure, but in some cases owing to their size and dominance over a small garden patio area, etc. The wrong tree planted in the wrong places, obviously. So this will be an experiment, to see what does happen. I took my front garden Kanzan cherry off the pollarding list, and it will remain intact, owing to the possible problem with "water sprouts" etc. and because it should match the others left intact out front, really, and also because I don't really think this pollarding process will work successfully. I love the comment about a process developed when serf labour was cheap! I do see some smaller ornamental cherry or plums pollarded when younger, I guess, growing in in our immediate neighbourhood, and they are fine. One can see where the tipping of branch ends was done, but growth is good and well-selected from those ends, and whoever maintains the trees seems to have kept them under control, but they don't look recently pruned. Interesting...

 

What constitutes "fine" in this case varies with an observer's point of view. Those not familiar with and appreciating the normal, natural growth of a particular kind of tree may not see the deformity and decline that heavy pruning has produced in a given specimen.

Turnbull is a woman.

 

Thanks, Ron. By anyone's standards the ornamental cherries/plums/crabapples I see as pruned or "pollarded" successfully and looking "fine", in my words, on my nearby street would, I think, by anyone's standards be considered attractive and well-maintained trees -- they resemble what in my mind MAY be the way bearing fruit trees are pruned in orchards...lower than normal. I have read enough on the web to see how that is done, and I have never been able to square that process with the advice not to "top" trees. I guess there are several kinds of "topping" and some is ok, because you are choosing a new leader which happens to bend downwards if that is the way the tree grows. In contrast, I have read that the Kanzans are grown in Japan in parks and allowed to grow freely, in large open spaces [funny, I didn't think they had too many of those over there] and further, that they would never be planted in Japan as courtyard trees. And, on one street in old Victoria West here I have seen the results of a one-time radical pruning sometime in the past, on an unknown variety of trees, I don't know if they bloom in spring or not, or what they are, but which resulted in weird overgrowth of water sprouting which has ended up forming a thick canopy interleaved together right over the roadway, creating a thick tunnel of overgrown trees! They didn't do the subsequent pruning, I guess. So, we are doing this horticultural experimenting in this complex with the 3 back hidden trees to see what does happen. I don't want to hack trees to death either, but there is a problem with these large over-grown cherries with huge thick trunks, big roots which are no doubt contributing to driveway cracks, etc., and in most cases growing very tall, and the fact that they tower over the front doorway garden patches, and annoy some of their owners. They don't annoy me, I like them, but I can see they dominate. A lot of older folk, I find, get to dislike trees, it's silly, but they do, they find them messy and requiring a lot of cleanup. A landscape without trees, though, would be an awfully dull place. So I regard your opinion highly and always read your observations here, but sometimes the situation is such that the owners are going to do something anyway, for good or ill. And, Cass Turnbull's book is fun to read, she is very forthright in her opinions, and it is a very valuable book. Her tips on shrub pruning are fabulous.

 

That is a common mistake, pruning ornamental trees in the manner of orchard fruit trees in a commercial orchard. Flowering crabapples in particular are often ruined by this - as are actual orchard fruit trees outside of orchards, which when heavily topped often prove to be rotten when climbed into some years later.

Cutting a long-established tree in half and other brutalizations are never good practice, even in a commerical orchard where one may sometimes see trees so-handled pulled up and piled together to be burnt, production no longer adequate or some other problem having been identified. No tree functions well cut to look like a hat rack or laundry tree, including orchard apples which are actually quite prone to burning of the bark and subsequent rotting of the main branches when severely topped.

 

When the choice is remove or pollard, pollarding makes the most sense. The American bias against pollarding surprises me since Americans are enamored of so many other aspects of European gardening. Many of Europe's most ancient trees have been pollarded at one point or another (e.g. Epping Forest). And Europeans have been pollarding broadleafed ornamentals for centuries as well as the more commonly recognized oaks, beeches and willows. For instance, many ancient crabapples can be found in the UK and in Northern Europe. Finally, many Americans think that once a tree is pollarded it must be re-pollarded every year or two. (This form of pollarding was done for fodder.) Pollarding cycles range from one year to fifty.(See this article by a British tree expert which reviews pollarding across Europe:http://www.maisonbotanique.com/dyn/12acte_2_read.pdf .) My favorite pollards are re-pollarded on a cycle of 15 years or more (a form of pollarding done for wood).

 

EUgardener, that was a really interesting article. Thanks for furthering my education on pollarding, which I've just got interested in after seeing so many pollarded street trees in San Francisco.

The article does make the point that pollarding was done to provide leaves or wood from the cuttings. With ornamental trees, however, the main purpose for the tree is to be, well, an attractive ornament. I think several of the photos in the article speak for themselves in that regard. On the other hand, the San Francisco trees, many of them sycamores, do look quite nice and certainly a lot better than Vancouver cherries pruned down the middle to make room for overhead wires.

 

Cherry trees are comparatively short-lived and disease- and pest-susceptible. They are mostly unsuited to heavy pruning. Even in an orchard setting you would undertake annual pruning from the start of the planting rather than going through long-established trees and cutting them in half.

 

I agree that ornamental cherries are not the best tree to pollard. As for short lived, I disagree. Japan twice gave gifts of the trees to the US -- in 1965 and in 1912. The 1965 trees are thriving at the Tidal Basin in Washington, D.C. I believe many of the trees from 1912 still exist. With pollarding, it is often a question of time. Some tress will look good in their first year. Others will take several years to recover. Again, most broad leafed trees will tolerate pollarding. With a cherry, I think it will take about three years before you'll see vigorous blooms.

 

A friend who has been to the tidal basin says the Yoshino cherries don't like it there and have mostly been replaced. If any from 1912 are still there that is only 97 years - not much for a tree.

Why do something to a flowering tree that results in a 3 year interruption in normal flowering?

"The pruning of nearly all ornamental Prunus is best kept to an absolute minimum. Where formative pruning is necessary, it should be done as early as possible, aiming to create well-formed trees that will need little further attention in later life. Keeping pruning wounds small, and pruning in midsummer reduces the risk of diseases such as silver-leaf. In common with the stone fruits, ornamental Prunus are sometimes affected by gummosis"

--Brickell/Joyce, PRUNING & TRAINING (1996, Dorling Kindersley, London)

About Japanese flowering cherries specifically the same reference says

"In general, do not prune unless absolutely essential. If removing dead wood or crossing or rubbing branches, the tree's natural habit, whether fastigiate, spreading, or weeping, should be enhanced and not compromised by pruning operations. All pruning must be undertaken early in the tree's life"

"On established trees, prune only to remove any dead, diseased, and damaged wood, and also any suckers that appear below graft unions, pruning in summer. Drastic pruning to renovate a tree is seldom successful" [emphasis mine]

 

May I interject, that the solution is quite simple...your strata will inevitably cut down these Kwanzans, and that is not the real issue here. Put in a planter box once the trees are cut to the ground, and replant site appropriate plants, shrubs or height restricted trees. This should save you from endless bickering, bantering and keeping your pension funds safe from the denizens of tree pollarding companies.... speaking the truth, now what to plant? Have a plan and think of the future this time! There are so many inexpensive options, drought tolerant plants/shrubs/trees... your local nursery will aid you here... please remember to keep the landscaping height restricted, to eliminate future maintenance costs, this will be a long term benefit to your complex's contingency funds....

 

Well, just to muddy the water, here's a pollarded cherry in Vancouver, at 1st and Maple. I'll have to check what this looks like later in the spring. I have no idea what cultivar it is.

 

Judging from crown structure unless grafted low or raised from a cutting will be liable to be mazzard rootstock.

 

Rats. I forgot to check and I've missed it. It has very hairy leaf undersides and bright red glands at the base of the leaves. Or do the glands all get that colour? I haven't seen any that colour before and I don't recognize those leaf margins. The bark is quite shiny and reddish but not peeling.

 

I re-read this entire thread and was glad the last entry revived it. I will try to get my camera up and running [drat thing, I keep forgetting how to use it, it is digital but aggravatingly software-based re settings and I wish it had some physically-based setting switches instead of ?able icons on the display... give me a few days to do this, busy at moment.

The above pollarding took place, and it is too soon to tell what the real end results will be.

Thank you everyone for getting so involved and for a lively discussion. I did not follow all the latter postings, must have been away from the forum for some little while or the email notifications did not happen.

I like the suggestion for the planter box, as digging out the roots of these one-day-to-cut-down trees would be a huge problem, I presume. K Baron's comment here is the one I am referring to. A planter box would raise the planting above the root zone of the old tree. However, it would have to be maintainable over a long period, one wouldn't want deteriorating wood, etc., etc. I would imagine we'd come up with a well-planned small tree or suitable shrub, after this experience. I've been researching that choice a bit, and thought of Stewartia or Dogwood, very small crapapple maybe... but not a serious issue yet.


I wish I knew what a mazzard was -- I'll look it up on the Web; the trunk of my cherry is huge, it's a bit tortuous at the base and hard to see the graft but I'll get it in a photo one of these days.

 

Janet, if you miss responding to one notice, you don't get any more notices until you visit the thread again.

Mazzard is sweet cherry, Prunus avium, a very strong and fast grower that is used as the rootstock of a lot of ornamental cherries, probably all the ones you see with big fat trunks and thin limbs starting out from the same place on top of them. As the trees grow, the mismatch in growth at the graft point provides an entry point for disease. Look around for trees that are Kanzan on top or on one half and a small single white on the rest - there are lots of those around, where the mazzard rootstock growth got out of hand, or even completely took over.

 

Speaking of pollarding, which we haven't done for a while, these cherries at Harrison Hot Springs don't look so bad, except for the one in the middle photo that looks more butchered than pollarded, in the background next to the left of the featured tree. I can't tell whether they're still being pollarded or whether now they're just pruned into this round shape.

No-one could tell me what cultivar these are - I was told some are white and some are pink, but the person who told me couldn't remember if they all come out at the same time. Almost every tree in the town of Harrison seems to have been pollarded (only a slight exaggeration). It's amazing. I've never been there in the spring or summer to see what they look like. But the cherries were said to be "spectacular". I wish we had a scout out there who would post a photo when they're in bloom.

 

What a wonderful offering your posting provided. I will send you progress photos on this thread. Our landscaper did the pollarding last spring, and things are progressing nicely. The new growth now needs to be re-pruned, and he will be doing that shortly. Plus some additional pollarding of trees awaiting this operation. I think it will be successful. Please forgive my lack of response for a bit, many things intervened and many other plants distracted me! Now I have to clear the decks of various strata concerns this week but in a week's time if not before I will get some photos posted of our progress here. I put so much effort into flagging attention and getting these responses that I owe it to you all! Jog me if I lag again!

 

The Harrison examples (a make-work project in their own right), have not technically been pollarded. Pollarding entails repeated heading-back to a permanent stubby framework. It appears that Harrison's pruner, on the other hand, chooses his/her cuts in a different place on the tree each time. Fascinating.

Spectacular, they say? That's a spectacular set of carbuncles on the trunk of the first one. Can you say bacterial canker? Yikes! I for one think it's best that we don't know which cultivar it is being abused. I'm not sure I want to be that familiar with the patient.

 

Hello all & particularly Janet Doyle,
I was pleased to find this thread as I have a similar problem. We have a very large healthy unidentified ornamental pink cherry in our driveway less than 8' from our neighbours garage.
From the descriptions it may be a Mazzard type as it has a very straight, very thick trunk with all branches sprouting directly from the top. Some branches have been pruned before - possibly well over 15 years ago - hard back to the trunk and survived. Although it should have been better managed after as it is a bit of a tangle. ,
Recently the neighbours complained about the quantity of petals covering & sticking to their cars (despite it's beauty in flower, a problem we have with it as well!) They would like us to cut it down. I am always reluctant to fell trees - too many forests disappearing but I am aware that the tree is way too close to their foundations - although the tree was there first! As a last ditch I am considering "pollarding" it & wonder what results you had with your experiment?
By pollarding I mean in the european sense - close back to the trunk.