Coppice To Renovate Overgrown Shrubbery

Coppicing stimulates vigorous new basal growth.

Pollarding is extreme pruning. It removes all but the most substantial of limbs and trunks. Coppicing is even more extreme. It leaves only stumps above ground. Both are common and respected arboricultural techniques outside America. However, they are vilified here. Actually, very few arborists here know how to pollard and coppice properly, or admit to it.

There are many valid reasons to pollard or coppice trees or big shrubs. Both techniques stimulate vigorous growth. Lush foliage of such growth is useful as fodder, particularly for silkworms. Elongated stems of such growth are useful for basketry and kindling. Species that bloom on older stems can not produce pollen or messy fruit after annual procedures.

Although silkworms, basketry and such are unimportant within an average home garden, proper pollarding or coppicing enhances vigor. This enhances the bloom of species that bloom on new stems. Vigorous growth of pollarded crape myrtle is atypically resistant to mildew, and also blooms zealously. Coppice pruning eliminates unsightly thicket growth.

Pollarding is generally useful for trees and large shrubs that retain primary trunks. Only a few of the many species that inhabit home gardens are conducive to it. Since secondary growth is initially structurally deficient, it will most likely need subsequent pruning during subsequent winters. Some vigorous pollarded trees are dependent on annual pollarding.

Coppicing is generally useful for large and vigorous shrubbery, and perhaps a few types of trees. Coppiced shrubbery is not as reliant on subsequent pruning as pollarded trees. They either benefit from pruning as they grow anyway, or do not get too heavy to support their weight. Both coppice and pollard pruning can happen only during winter dormancy.

Realistically, the majority of plants in home gardens are conducive to neither coppice nor pollard pruning. Cypress hedges die if cut back to stumps. Grafted plants, even if pruned above their graft unions, are likely to regenerate from their understock. However, some of the most popular hedge plants, such as privet, holly, photinia, osmanthus, English laurel and bottlebrush regenerate splendidly.

Saint John’s Wort

Saint John’s wort blooms somewhat late.

Although it shares the same common name, Hypericum beanii is not the same sprawling Saint John’s wort that is now so aggressively naturalized within some local ecosystems. It is shrubbier and much more docile. Mature specimens get no more than three feet high and wide. It should be evergreen here, but can get sparse through cooler winter weather.

Bloom begins in the middle of summer and continues at least to early autumn. Cheerfully bright yellow flowers are two inches wide, with five rounded petals around fuzzy centers. The light green and oblong leaves are about two inches long. Stems are rather wiry, and can eventually get shabby. Coppicing as winter ends stimulates fresher vigorous growth.

Saint John’s wort prefers sunny and warm exposure. It is otherwise not very demanding. Regular watering enhances bloom. Yet, established plants can survive without watering. Where coppicing (cutting back to the ground) in late winter is not a problem, Saint John’s wort performs well as a low hedge, or unshorn border. Frequent shearing inhibits bloom. Rust is a potentially bothersome fungal disease.

Coppicing And Pollarding Annoy Arborists

Pollarding is a long term commitment.

Coppicing and pollarding are the most extreme of pruning techniques. They may also be among the oldest in some cultures. Yet, arborists are correct to condemn both as improper. Coppicing is the complete removal of all stems and trunks back to a stump. Pollarding is the removal of all stems back to main stems and trunks. Both procedures happen in winter, annually or every few years.

Both coppicing and pollarding stimulate vigorous and prolific cane growth during the next season. Lush foliage of such growth is useful as fodder. Foliage of pollarded mulberry is the primary food of silk worms. Canes are good kindling for the following winter. Thin canes of various species are useful for basketry. New foliage of pollarded eucalypti is useful for both essential oils and floristry.

Of course, few rely on modern urban gardens for fodder, kindling, eucalyptus oil, or basketry material.

Arborists disapprove of coppicing and pollarding because both techniques ruin trees. Many of such trees are too structurally compromised to support the weight of secondary growth after the first year. Consequently, they rely on annual coppicing or pollarding. Some trees will support their weight for a few years. Strangely though, many properly coppiced or pollarded trees live for centuries.

Coppiced trees generate from stumps of cut down trees. Ideally, they begin young. Grafted trees are less cooperative. They are likely to generate suckers below their graft unions. Pollarded trees get to develop their main trunks and limbs prior to their first pollarding procedure. The locations of the first pollarding cuts is very important. Subsequent pruning will be back to the same locations.

Distended ‘knuckles’ develop after repeated coppicing or pollarding back to the original pruning sites. Pruning must be flush to these knuckles. Stubs interfere with healing. Annual pruning leaves smaller wounds than less frequent pruning. Secondary growth should be able to overgrow wounds efficiently. Cutting below knuckles leaves wounds that may be too big to heal before they decay.

A Strong Foundation

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Before: Camellias left the foundation exposed a long time ago, but instead obscured the view from the windows above.

‘Foundation planting’, which most of us think of as vegetation intended to merely obscure a foundation behind lower and prettier plants, has a simple utilitarian origin. Before homes were so commonly outfitted with rain gutters like they are now, densely shrubby foundation plantings diffused water that fell from eaves, and limited splattering of mud onto foundations and walls.

Nowadays, foundation planting only needs to look good, and maybe obscure crawlspace vents or exposed undersides of decks. They might be allowed to get as high as window sills, or higher.

These camellias got more than a bit too high. They had not obscured the cinder block foundation in a very long time, and did not contribute much to the shingled wall above. What was worse was that all of their best foliage and bloom obscured the view from the window above, and obstructed sunlight to the interior. They were impressive specimens, but were not doing their job.

We tried to prune their canopies lower and thinner, in order to promote more lower growth that we could prune down to later. They responded by merely replacing what was pruned away, exactly where it was pruned away from. We considered relocating the camellias to where such big and lanky camellia trees would be desirable, but they are too old and firmly rooted in place.

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After: Camellias can either start over or die.

The only option was to coppice them. It was quick and easy. We cut them to the ground with the expectation that they will either regenerate from their stumps or die. If they die, we will not miss them. (Okay, I might.) The new growth will obscure the foundation well, and after a few years, should resume blooming. They will be patchy if some but not all do survive, but we tried.

The remaining sculptural specimen obscures no windows.

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Stumps are a few inches high. Any new growth should hopefully develop on top, just above grade.

Silver Lining

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This little silver dollar tree did well with a second chance.

Among the more than seven hundred species of Eucalyptus, nomenclature gets confusing. It certainly does not help that some species have multiple common names. Eucalyptus cinerea is a rather distinctive species with at least two equally distinctive common names. The problem with these names is that, although sensible in Australian, they are not so sensible to Californians.

‘Mealy stringybark’ is a name that must describe something of the physical characteristics of the species. The bark is rather stringy, but no more stringy than that of so many other species. The glaucous foliage might be described as mealy in Australian English. ‘Argyle apple’ is a weirder name. Again, it must make sense in Australian culture. I just know it as ‘silver dollar tree’.

A few years ago, I acquired a severely disfigured and overgrown #5 (5 gallon) specimen of silver dollar tree, along with three comparable specimens of dwarf blue gum, Eucalyptus globulus ‘Compacta’. They were about to be discarded from the nursery where I found them. They got canned into #15 cans, and coppiced back to their distended lignotubers. All regenerated nicely.

Two of the blue gums found appropriate homes. One remains here, and was coppiced again last year. The silver dollar tree stayed late too, but happened to get planted into a landscape last autumn. It is developing into such an appealing tree that one would not guess that it had experienced such neglect and subsequent trauma. The exemplary silvery gray foliage is so healthy.

As it regenerated after getting coppiced, the strongest of the new stems was bound to a stake to form a single straight trunk. All smaller basal stems were pruned away after the first season. The little tree cooperated through the process, and now lives happily ever after. I still do not know its name.

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Silver dollar tree produces strikingly silvery foliage.

Pollarding And Coppicing Appall Arborists

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Pollarding is disturbingly severe but effective.

Very few arborists in America condone the extreme pruning techniques known as pollarding and coppicing. Both techniques essentially ruin trees, and deprive them of their natural form. Affected trees likely require such procedures to be repeated every few years or annually. Otherwise, they are likely to succumb to resulting structural deficiency. Restoration of such trees is rarely practical.

Pollarding is severe pruning to remove all except the main trunk and a few or perhaps several main limbs. Coppicing is even more severe, and leaves only a stump. Both are done while subjects are dormant through winter. Most or all new growth that develops is spring is concentrated around pruning wounds of the previous winter. Some coppiced stumps generate growth from the roots.

If pollarded or coppiced annually, all growth that developed during the previous season gets pruned cleanly away to where it grew from since the previous procedure. Distended ‘knuckles’ develop at the ends of pollarded limbs or coppiced stumps as the pruning is repeated for a few years. ‘English’ pollarding leaves a well oriented stub of any desired length to slowly elongate each knuckle.

Pruning wounds should be as flush to each knuckle as possible, without intrusive stubble. The many small pruning wounds left on each distended knuckle will compartmentalize (heal) efficiently as new growth develops during the following season. Pruning below a knuckle might seem to be more practical, but leaves a single but big wound that could decay before it gets compartmentalized.

Delaying pruning for a few years creates bigger wounds, and allows innately structurally compromised stems to get heavy.

Pollarding and coppicing were developed a long time ago to produce kindling, fence stakes, cane for basketry, and fodder for livestock, as well as silkworms. Nowadays, it is done to contain big trees, enhance the size and color of leaves, produce juvenile foliage, produce colorful twiggy growth, or prevent unwanted bloom or fruit. Not many trees are conducive to such severe techniques.

Bad Pollard


P90831KJust about any other arborist will insist that any pollard is a bad pollard. I am not any other arborist. I have no issue with pollarding certain trees properly.

Pollarding is severe pruning that removes all growth that developed since the last pollarding procedure, leaving only a main trunk and a few main limbs. It is done while trees are dormant in winter, and must be repeated either annually or at least every few years, before the resulting growth develops into major limbs. Pruning must be very thorough and neat, leaving no stubs.

Most new growth develops from where older growth had been pruned away during the previous winter, with only a few adventitious stems possibly developing on the main limbs or trunks. Distended ‘knuckles’ develop where this growth repeatedly gets pruned away and regenerates. All subsequent pollard pruning must be done only on the outside of these knuckles, not below.

It may seem easier to cut entire knuckles off with fewer big cuts rather than cutting all the secondary growth off with so many more cuts. However, as new growth develops, the many small cuts on the distended knuckles will be compartmentalized (healed over) much more efficiently than fewer but larger wounds. Wounds that compartmentalize too slowly stay open to decay.

Once pollarded, a tree will always need to be pollarded, or at lease pruned regularly to compensate for compromised structural integrity. Secondary growth is innately vigorous and heavy, but weakly attached to the main limbs.

Pollarding is done to produce an abundance of lush foliage, to produce an abundance of twiggy growth, or to deprive a tree of bloom. Pollarded mulberry trees provide lush foliage to feed silkworms. Pollarded willow trees provide many uniform limber canes for basketry. Pollarded privets are unable to bloom and bother those who are allergic to their objectionably fine pollen.

Well, enough about pollarding.

I pollarded a blue gum, Eucalyptus globulus, for the second time earlier this year. It was done dangerously late in the season, and at the same time that the roots of the tree were brutally damaged by relocation. (It is a canned tree that rooted into the ground.) The tree has no branches, but only a single ridiculously bare trunk with a silly new knuckle on top. Oh, the shame!

As you can see, the unfortunate tree has not grown much since then. It is now getting to be September, so the tree will not be growing much through autumn. As much as I would prefer to pollard this tree annually, I will likely not pollard it this winter, but instead let it grow for another year before pollarding it again. The blue juvenile foliage is exquisitely aromatic, but scarce.

For this picture, I could have moved the tree away from the fence that it is tied to for support, but the barbed wire somehow seems appropriate.

Six on Saturday: Oh, The Shame!

 

Not my shame of course; but that of the trees in the pictures below.

Do not try this at home. I only did it because I am a horticulturist and arborist; and I happen to be one of the last arborists in America who condones coppicing and pollarding, which are depicted here.

Coppicing is cutting trees or shrubbery down to the ground annually, or at least regularly every few years or so. Some coppiced trees form basal burls or lignotubers. Some just form thicket growth that replaces itself after getting coppiced back to the ground.

Pollarding is similar to coppicing, but rather than cutting all growth back to a stump or stumps at ground level, it involves pruning all growth back to the same distended knuckles at the ends of a few main limbs annually, or at least regularly every few years or so. It is done in such a manner that the pruning wounds are compartmentalized by the new growth of the following year. Knuckles can be elongated by leaving single short stubs.

There are a few reasons for coppicing and pollarding. Some subjects develop an abundance of appealingly lush foliage. Some develop an abundance of appealing or useful twiggy growth. Coppiced red twig dogwoods are much twiggier and more colorful while bare in winter. Pollarded or coppiced willows produce an abundance of canes for basketry. White mulberries are pollarded to provide an abundance of lush foliage to feed silkworms.

I coppiced a Eucalyptus globulus ‘Compacta’ and pollarded a Eucalyptus globulus for two main reasons. Both are such problematic trees that I do not want to plant either into the ground, so must keep them contained. Also, I want the remarkably aromatic juvenile foliage that develops in response to coppicing and pollarding.

1. Eucalyptus globulus ‘Compacta’ coppiced stump. It is not such a great example of a coppiced stump, since the tree did not grow enough two years ago to get coppiced last year. Consequently, the few main trunks that were just recently coppiced are already starting to form their own separate lignotubers on top of the original, which is now rotting below. Soon enough, they will fuse to form a single lignotuber, concealing the evidence.P90601

2. Eucalyptus globulus ‘Compacta’ before getting coppiced. It is quite small for a specimen that was not coppiced last year.P90601+

3. Eucalyptus globulus ‘Compacta’ after getting coppiced. Rhody is not impressed.P90601++

4. Eucalyptus cinerea in need of pollarding. This tree grew too big too fast to survive any longer in the relatively small #15 (15 gallon) can. Fortunately, in just a few days, it will instead get installed into a landscape where it can disperse roots and mature into a normal unpollarded tree. After a few years, it might get pollarded anyway, just to produce silvery juvenile foliage withing reach of the ground, but that is not a concern just yet.P90601+++

5. Eucalyptus globulus pollarded knuckle. This is only the second pollarding procedure for this subject. The first procedure involved lopping the lanky single trunk off right here where the knuckle is now. The multiple limbs that developed were just recently lopped off, leaving this distended knuckle to repeat the process, hopefully annually.P90601++++

6. Eucalyptus globulus pollarded trunk. This is why Eucalyptus globulus should not get pollarded! They look ridiculous if deprived of their naturally elegant form. They do not look much more dignified with multiple pollarded limbs. Oh, the shame!P90601+++++

This is the link for Six on Saturday, for anyone else who would like to participate:

https://thepropagatorblog.wordpress.com/2017/09/18/six-on-saturday-a-participant-guide/

Horridculture – Bad Pollarding And Coppicing

P90508Pollarding and coppicing are proper pruning techniques. If you think you are an arborist who believes otherwise, do not waste my time arguing about it. More than likely, you are neither as educated nor as experienced as I am with such matters, or you work exclusively with trees for which such procedures would be very inappropriate.
Well, yes, pollarding and coppicing are very inappropriate for the vast majority of trees and shrubs out there. Furthermore, even for those trees and shrubs that they are appropriate for, such procedures are very rarely done properly here in California. Most attempts at pollarding and coppicing are really horrid!
Take these blue elderberries and mock oranges for examples. They were mutilated last summer to improve the view of the historic Felton Covered Bridge. It sort of accomplished that objective, although the improved view of the Bridge was then cluttered with the disfigured and mostly bare trunks and limbs of the brutalized shrubbery below. Because they were chopped back too late in summer to grow much, they stayed that way until now.
So it is spring, and the shrubbery is growing from the tops of the mutilated but tall trunks and limbs, right back to obstructing the view of the Bridge. They will likely get chopped when they get to be too overwhelming, which again, will be in late summer, repeating the process. It would be better to just remove the shrubbery not only because it would be less work, but also because the shrubbery is so unsightly when it gets chopped!
OR; the shrubbery could get coppiced. Both blue elderberry and mock orange respond favorably to the procedure. If coppiced, or in other words, if pruned back to the ground annually each winter, they could regenerate fresh new growth each spring, but not get big enough to crowd the view of the Bridge by the following winter, when they get coppiced again. The elderberry would not bloom or fruit; but that is not important here anyway.
Coppicing takes advantage of the natural dormancy and regenerative processes of the plants. Starting over fresh each spring and growing uninterrupted through summer is more natural for them than trying to recover from getting brutalized while they are actively growing in summer. Since they start the process at ground level, they have room to grow without interruption. If cut back only as much as necessary, they have no room to grow.

Knucklehead

P90413KThis is the beginning of one of several new knuckles on a pollarded crape myrtle tree that was pollareded for the first time just this past winter. It was quite a mess of thicket growth that was too congested to bloom well. It is also located in a confined situation where it could not just be groomed, pruned up for clearance, and then just left to develop a larger canopy higher up. Pollarding will both contain it, as well as invigorate healthier growth.
New shoot growth now emerging from the ends of limbs that were pruned back last winter will elongate and eventually bloom through spring and summer. Next winter, after all the colorful autumn foliage has defoliated, the tree will get pruned back to these same knuckles to repeat the process. Stems will get cut back as neatly as possible, leaving no stubs, but such pruning causes knuckles to become slightly more distended as the develop.
Minor shoot growth that develops elsewhere on the mature stems below the developing knuckles should be removed as it appears. It is easy to knock off now, before it gets big enough to need to be pruned off. Knocking it off or ‘peeling’ it off, as drastic as it sounds, is actually better than pruning it off. It removes more of the callus growth that is likely to develop more stem growth later. New growth should be concentrated into the knuckles.
Pollarded crape myrtles bloom later than those that are not pollarded, but they bloom more profusely. They are also more resistant to mildew, and develop better foliar color in autumn.
The picture below shows the same crape myrtle that I got the picture of the single knuckle above from, shortly after it was pollarded. This picture was used another article at:
https://tonytomeo.com/2019/03/16/six-on-saturday-picture-dump/P90316++++