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Pollarding Is Extreme Tree Pruning

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Pollarded knuckles look like science fiction.

Most arborists insist that pollarding is horticulturally incorrect. However, most of us who pollard trees in our home gardens are not arborists. Pollarding is technically detrimentally disfiguring to trees. However, some trees that are naturally short lived can live much longer if pollarded properly. That is the trick; doing it properly. Pollarding is certainly a distinctive pruning style that is not for everyone, but can be both practical and sustainable in certain situations.

Pollarding is an extreme pruning technique that involves the removal of all or almost all of the stems that grew since the last time the technique was done. The new growth gets cut back cleanly to distended ‘knuckles’ that develop at the ends of the original stems. Traditionally, one or two strategically aimed stubs from the removed new growth are left on each knuckle to form a new knuckle a bit beyond knuckles of the previous year. Locally though, stubs are typically omitted.

New growth must get cut back cleanly so that the wounds can get compartmentalized (healed over) as efficiently as possibly. Stubs interfere with this process. If one or two stubs are left on knuckles to form new knuckles, they should be long enough to get some distance from the original stubs, but short enough to not be too awkward. Knuckles should not get cut off! Such large wounds do not compartmentalize fast enough to avoid rotting.

Pollarding can only be done in winter, both because plants are dormant, and also because the weather is not so dangerous. New growth starts to shade exposed bark before it gets scalded by intensifying sunlight and heat in summer. Once they come out of dormancy, plants would be seriously distressed by such severe pruning. Because new growth is so vigorous after pollarding, it can become sloppy if pollarded less than annually. Some plants that grow slowly or produce stout stems may get pollarded less frequently.

London plane (sycamore) and fruitless mulberry are the most commonly pollarded trees. Silver maple, silk tree and various elms, willows and poplars adapt well to pollarding as well. Locust and purple leaf plum can be pollarded, but will be deprived of bloom. Bottlebrush can bloom later in the same year after getting pollarded, and probably will not need annual pollarding anyway. Pollarded bay trees can be kept small, and will provide better herbal foliage. Certain eucalyptus can be kept juvenile if their juvenile foliage is more appealing than their adult foliage.

Posted on by tonytomeo · 3 Comments

Figs Are Easy To Propagate

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Some grasses can propagate by division.

The easiest way to propagate new fig trees may seem to be violent, but it works. Basal shoots that grew last year from the roots near the trunks of ungrafted trees can simply be torn out of the ground with as many attached roots as possible. These shoots can then be planted directly wherever new trees are desired, and watered in. Larger shoots may need to be dug out, and might do better if pruned down to just a foot or two tall when planted. Smaller shoots can be potted to grow through next summer, and then get planted in the ground next winter.

Tearing the shoots off in this unpleasant manner is effective for two reasons. It gets the most roots for the shoots to help the grow into new trees. It also removes more of the burl growth that produces the shoots than simply cutting the shoots neatly. Even if copies of the original tree are not desired, the basal shoots must be removed anyway. Simply pruning them away leaves more burl growth so that more shoots grow back next summer. Ideally, well maintained trees should actually not produce basal shoots.

Fig trees are innately easy to grow from basal shoots or cuttings while dormant through winter. Basal shoots, even those that get pulled without any obvious roots, will develop roots more efficiently than stem cuttings that were never in contact with the soil. However, if no basal shoots are available, stem cutting work just fine. Furthermore, grafted trees (which are quite rare) can only be copied by cuttings from above the graft. Basal shoots from below the graft will only produce copies of the understock.

Just as unwanted basal shoots and cuttings from pruning scraps can be grown into fig trees, overgrown perennials in need of thinning can be divided to propagate more of the same. Lily of the Nile, red hot poker, daylily, mondo grass, African iris, terrestrial yuccas, some ferns and some grasses are not only easy to propagate by division through winter, but many perform better if divided every few years or so, before they get too crowded. The common giant yucca develops big trunks instead of clumping shoots, but can be propagated just as easily from big cuttings.

Posted on by tonytomeo

Fruit Trees Need Specialized Pruning

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Even almond trees need some pruning.

For centuries, fruit trees have been bred to produce unnaturally abundant and unnaturally big fruit. That has worked out well for those who enjoy the resulting fruit. It is not such an advantage for the exploited trees that must produce it. Without specialized pruning, most of such trees are unable to sustain healthy development of all the fruit they could potentially produce, or support the weight.

Specialized pruning concentrates resources into less excessive fruit of superior quality. It improves structural integrity of limbs that support the weight of all the fruit too. Trees that produce smaller and lighter fruit, such as cherries, may only need to be trimmed occasionally to eliminate structurally deficient growth. Heavier fruit, such as peaches, necessitates much more aggressive pruning.

Almost all deciduous fruit trees should be pruned about now, before they bloom and foliate at the end of winter. Such pruning is too severe to be done while the trees are active in spring. Summer pruning to maximize production within less space is the only practical option to dormant pruning. Evergreen fruit trees, such as citrus and avocado, should not be pruned or groomed during winter.

The main group of deciduous fruit trees that require dormant pruning in winter are stone fruit, of the genus Prunus. This includes peach, nectarine, apricot, plum, prune, cherry, various hybrids and almond. The second main group are pomme fruit, such as apple, pear and quince. Fig, persimmon and grapevines, as well as roses, need specialized and perhaps very aggressive pruning too.

Dormant pruning of deciduous fruit trees, roses and grapevines is too complex to describe adequately here in just a few paragraphs. Nonetheless, those who grow such plants must be aware of how important it is, and ideally, know how to do it. Nowadays, it is nearly impossible to procure services of horticultural professionals who know or care how to execute such procedures properly.

Posted on by tonytomeo · 4 Comments

They Don’t Know When To Quit

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The good news is that these billowy white blooms were not wasted.

The main difficulty with such a mild climate is that many plants do not get sufficient chill in winter. Several types of apples do not perform well here without it. Only a few are productive in Beverly Hills (in the Los Angeles region), where I sometimes need to modify my gardening column accordingly. A few of my neighbors here somehow grow peonies; but I do not even bother.

Even plant that require more chill than they get here seem to be aware that it is cooler at this time of year. Their deciduous foliage turns color and eventually falls to the ground. They just want the weather to get a bit cooler and to stay cooler for a bit longer before they are convinced that it is really winter. Otherwise, they think that autumn simply merges directly into spring.

I really do not know what hydrangeas are thinking though. They perform about as well in milder climates of Southern California, and may not bother to defoliate completely if old foliage can linger until it is replaced by new foliage. In the mildest climates, bloom is merely subdued through winter, but might continue sporadically. I am not convinced that they need any chill at all.

The hydrangeas here get pruned shortly after the roses, and almost as severely. (They are a bit more complicated than roses, and a bit less cooperative, but respond well to their pruning.) I started the process on Thursday with a few that needed to be relocated, and will be finishing on Wednesday or Thursday. Most of the remaining yellowed old foliage falls away in the process.

Their lingering bloom is a bit more disconcerting. I hate to waste what the old hydrangeas put so much effort into producing. Some of the best blooms were outfitted with a bit of eucalyptus foliage (since they lacked their own) and given away to others who work here. However, there were invariably some undeveloped blooms that were just discarded as they got pruned away.

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Undeveloped bloom was merely discarded with the rest of the debris.

Hydrangeas seem to appreciate a good chill, but do not seem to need it, or expect it to last for very long. I sometimes wonder if I could just groom them to remove old canes throughout the year rather than pruning them aggressively in winter. I do not remember ever pruning any in Southern California, but might expect them to be less responsive to the even milder weather.

For me, they would be easier to prune where winter is cool enough for them to be completely dormant. Without foliage, it would not seem like I would be pruning them while they are still active. Without bloom, I would not be concerned about the waste. I could just prune them like so many other deciduous plants. There really are a few disadvantages to mild winter weather.

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Hydrangeas that were transplanted got pruned and dug bare root.
Posted on by tonytomeo · 2 Comments

Winter Is For Dormant Pruning

P90316++++The internet makes it possible to communicate with people who enjoy gardening all over the World. It can be amusing to hear what garden enthusiasts in Australia are doing now in early summer. Is it always summer in Ecuador? A common theme in much of America is that there is not much gardening to do right now. It might be more accurate to say that no one wants to go out in the cold.

Where winter weather is too unpleasantly cold to work in the garden, many winter chores can either be done earlier in late autumn, or delayed until early spring. Such scheduling is not a problem, since the plants involved are so deeply dormant through such cold weather anyway. Until the weather warms a bit, they do not want to work in their gardens either. Scheduling is very different here.

Not only does mild weather facilitate gardening chores, but it necessitates the completion of certain chores before the end of winter. Many plants that are mostly dormant while the weather is cool are actually dispersing their roots now that the soil is moistened by winter rain. They will be ready to break dormancy weeks before they would where winters are colder. There is no time for delay.

With a few exceptions, winter is the season for pruning here. Maples and birches should have been pruned earlier, or should be pruned later, so that they do not bleed sap. Citrus get pruned and groomed after the last frost because pruning stimulates new growth that is sensitive to frost. Early blooming flowering crabapples, flowering cherries and forsythias should get pruned after bloom.

Otherwise, most deciduous plants and many evergreen plants should be pruned in winter, while they are as dormant as they get. Pruning now will be less disruptive than it would be while they are more active. They wake up in spring and resume growth as if nothing happened, but relieved of the superfluous growth that was pruned away. Winter pruning is what fits best into their schedules.

Of all plants in the garden, deciduous fruit trees and roses rely on specialized pruning more than most others.

Posted on by tonytomeo · 3 Comments

Horridculture – Bad Guys

P91211Roots hold up trees. That is part of their job. They grow along with the trees they support, and disperse as necessary to maintain stability. Trees grown within the confinement of cans (pots) or boxes, and then installed into a landscape, are typically staked temporarily until their roots adequately disperse and stabilize. Once unnecessary, stakes and bindings must be removed.

Mature palms that get relocated are supported temporarily by guy wires. They are just too big to be supported by stakes. Because palm trunks to not grow any wider as at they grow taller, they are not damaged by the sorts of bindings that would damage the fattening trunks of other trees. Like stakes on other trees, guy wires must be removed as they become unnecessary.

Although they can be appropriate in unusual circumstances in which stakes would not be practical, guy wires are rarely used on trees that are not palms. Mature trees that get relocated can be guyed if too big to be supported by stakes. Because trunks and limbs of such trees expand (circumference), it is more important for guy wires to be remove when they become obsolete.

As useful as guy wires can be, they are more often used improperly or inappropriately. Firstly, those who install them rarely do so correctly, with the wires or cables as straight as possible between each end. Cabled anchors are usually pounded into the ground perpendicularly to the direction of the cable, so that the cable merely slices through the soil when tension is applied.

Once installed, cables are very often left in place long enough to constrict the growing trunks or limbs that they are attached to. Cables that apply too much tension or limit the motion of the trees they support (in the breeze) for too long will actually inhibit root dispersion. Trees will only become as stable as they need to be. Besides all this, lingering cables are just plain unsightly.

The cabled trees in these pictures demonstrate another set of problems that should be corrected by simple and necessary pruning, and comparably necessary adjustment of the automated irrigation. Guy wires should most certainly not be necessary for such mature trees of this species, and will interfere with necessary root dispersion without remedying the primary problems.

Firstly, the trees are too low and dense. Even if stability were not a concern, they should be pruned for a bit more clearance above the patio to the right of the picture, and perhaps allow a bit more sunlight to the plants below, even if only temporarily. More importantly, pruning would temporarily decrease weight and wind resistance of the canopies while roots adapt accordingly.

Secondly, the landscape is getting irrigated too much, even for the ferns in the background. This maintains soil saturation so that stabilizing roots can not disperse into deeper strata. Roots that might have extended deeper earlier will drown and rot. Until this happens, excessive irrigation promotes heavy superfluous growth that the compromised root system can not support.

Automated irrigation should be disabled for winter, and operated only manually and minimally if the weather stays dry long enough for the ferns to get drier than they are comfortable with. It can be adjusted accordingly when reactivated in spring. Even before that happens, and roots disperse, the guy wires can be removed as soon as these trees get pruned as they should be.P91211+

Posted on by tonytomeo

Arborists Specialize In Tree Horticulture

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Why is it so difficult to believe that there are so many different kinds of horticultural professionals? No one is ever surprised that surgeons, cardiologists, dermatologists, ophthalmologists and pulmonologists are all physicians. Yet, those who do not know better consider all horticultural professionals to be ‘gardeners’. This is actually more insulting to real professionals than outsiders can imagine, because the gardening industry is more dominated by non-professionals than any other horticultural industry.

Nurserymen, landscapers and florists are also horticultural professionals. Each of these basic categories can be divided into more specialized professions. For example, production nurserymen grow nursery stock or other horticultural commodities, while retail nurserymen maintain plant material only long enough to sell it. Maintenance gardeners are probably the most familiar of horticultural professionals because so many of us use their services around our home gardens.

Arborists are the horticulturists who specialize in trees, and really should be more familiar than they are. The only landscapes that have no possible use for their services are those that are devoid of trees. Even the most proficient of maintenance gardeners should not be expected to maintain large trees or diagnose potential arboricultural problems, not only because arboriculture is so specialized, but also because maintenance gardeners have their own specialties to be concerned with.

Because trees are the most substantial features of a landscape, and they have the potential to cause proportionate problems if not maintained properly, it is very important to have them maintained by qualified arborists. Those who are certified by the International Society of Arboriculture, or ISA, have passed an exam of their expertise, and maintain their certification with regular involvement with the ISA. Such involvement includes attendance to arboricultural seminars and classes.

It is ironic that some of the least familiar of horticultural professionals need to stay so dedicated to the maintenance of their credentials. Certified arborists can be found at the website of the ISA at isa-arbor.com.

Posted on by tonytomeo · 7 Comments

Horridculture – Sealant

P90810++++Grafting compound is a thick sealant applied to a fresh graft union to limit desiccation while the graft knits. A bit more typically gets applied to the cut distal end of the scion. There are various formulations of grafting compound, ranging from something resembling roof patch to a something with the consistency of thick paint.

The stuff, as sloppy and icky as it is, really is helpful. I can not imagine how big orchards were grafted before it was invented.

It is also useful for keeping cane borers out of the cut ends of freshly pruned roses. For those of us who remember how to prune roses properly, leaving only a few thick canes, grafting compound really is practical. I just don’t use it on roses because cane borers are not a problem here.

Since I do not use grafting compound on roses, and the plants that I graft do not need grafting compound, I presently have no use for it. I suppose I could use it on apple and pear trees, but it really is not necessary. When I get around to grafting apricots and peaches, it will only be for a few trees in my own garden, so I will just use candle wax.

This surprises people. At work, I am often asked about ‘painting’ pruning wounds and shiners as trees get pruned, presumably with sealant. Decades ago, it was actually commonly done. Even when I did my internship in arboriculture in 1988, some arborists were applying sealant because it was easier than arguing with their clients about it not being necessary.

The problem with applying sealant to large wounds is that is actually seals moisture within the otherwise exposed wood, and promotes rot. It is best to do nothing, and allow the affected trees to compartmentalize their wounds as they would do naturally if limbs were broken off by the weather. Trees know more about their processes than we do.

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Arborists Maintain The Big Trees

91106thumbThe trees know what time of year it is. Even evergreen trees have shed some of their older foliage through late summer. Deciduous trees generally start later, but will be more blatant about their process as they defoliate completely through autumn to winter. Some get strikingly colorful first, as if to brag about it. Foliage is not so important during shorter days and dimmed sunlight anyway.

By the time storms start to arrive later in autumn, trees intend to be ready. There will be less foliage to be blown by wind, or to absorb the weight of the rain. Remaining deciduous foliage is likely to be dislodged by wind and rain before supporting limbs succumb. Trees will be mostly dormant, so will not mind so much if a few minor limbs do happen to get broken. They know their routine.

For many types of trees, this is a the best season for major pruning. While dormant, they are much less likely to be offended by it. In fact, they sort of expect to wake up in spring with a few limbs missing. They do not distinguish what was pruned away from what might have been broken by the weather. Besides, it is better to prune questionable limbs civilly, before they get broken brutally.

Trees that are beyond reach will need the attention of professional arborists.

Arboriculture is merely the horticulture of trees. An arborist is therefore a horticulturist who specializes in trees. They assess the health, stability and structural integrity of trees, and prescribe any necessary arboricultural procedures. They or their associated crews are qualified to perform the work that the trees need. The most proficient of arborists are those who are certified with the ISA.

The ISA is the International Society of Arboriculture. ISA Certified Arborists have passed an examination of their arboricultural expertise, and maintain their credentials by continued involvement with ISA educational seminars, classes and workshops. Information about the International Society of Arboriculture and local certified arborists can be found at their website, www.isa-arbor.com.

Posted on by tonytomeo · 14 Comments

Work Day Renovation Of A Flowering Crabapple

P91020P91020+It is amazing what just a few parishioners and friends can accomplish in just a few hours from about nine to noon on Saturday morning. It is only happens a few times through the year, so we make the most of it to catch up on all sorts of maintenance and projects at Felton Presbyterian Church. (My parish should do this sort of thing.) I was there to work in the minimal landscape.

I started working with this ‘Prairie Fire’ flowering crabapple several years ago. As I pruned for clearance above the adjacent parking spaces and patio, I retained lower growth in the space in between. The tree bloomed too nicely to unnecessarily remove all that was right where it was most visible. Besides, from the patio, it was more visually appealing than a view of parked cars.

Then, I missed a work day. There were plenty of volunteers. There were plenty of power tools. There was plenty of enthusiasm. There was no horticultural expertise. Someone decided that my once exemplary flowering crabapple was in need of pruning, so executed the task with power hedge shears. The damage is irreparable. Lower growth is gone. Upper growth is mutilated.

It was very discouraging. It was done out of season, so I could do nothing to start to repair the damage at the time. There was not much left to repair anyway. I could only let the tree grow through a season so that there would be something to work with later.

Well, this was later. I would have preferred to wait for complete defoliation, but the tree is starting to go dormant now, which is technically good enough. I also would have preferred to prune less away; but really wanted to remove as much of the disfigured growth as possible.

I am less than pleased with the results. With all the disfigured lower growth removed, only the new upper canopy remains. The tree got what my colleagues might refer to as an ‘Ethiopia cut’, which is what much taller trees in Ethiopia get when their lower growth gets eaten by giraffes. It will be a long recovery.

The upper picture is the ‘before’ picture. The bright sunlight at noon does not look so good in the lower ‘after’ picture. I mentioned the Work Day and an update in my other blog, Felton League.