Too Much Of A Good Thing

Healthy growth can overburden tree limbs.

It was probably the extra chill this last winter that made some deciduous fruit trees bloom more profusely early in spring than they typically do. Unusually busy bees in some regions improved pollination and subsequent fruit set, although some was dislodged by late rain. The sudden warmth this last spring not only improved the flavor of fruit, but also made some grow larger than typical.

More and better fruit is usually what those who grow fruit strive for. The problem with some trees now is excess. After pruning our fruit trees every winter for a few years, we get to know how much to prune them to maximize productions without overloading the trees. When the trees produce more than expected, they may not be able to support the weight of their own fruit.

Many plum and peach trees have already dropped limbs that were overburdened with the weight of fruit. Nectarine, apricot, pluot (and aprium, plumcot and all those weird hybrids), and prune trees can potentially drop limbs as well. Even without breaking, heavy limbs can get disfigured simply by sagging downward. Broken or sagging limbs expose inner bark to sun scald.

Broken limbs obviously can not be salvaged, so can only be removed. They should be cut cleanly away without leaving stubs. Sagging limbs can be propped with notched stakes tucked under side branches that will keep them from sliding upward. The notches keep such stakes from sliding off to either side. Much of the excessive fruit can be removed from severely sagging limbs. However, if the fruit is so ripe that it will not be getting any heavier, there is no advantage to removal.

Formerly shaded bark that suddenly becomes exposed to direct sunlight should be shaded. If partly shaded though much of the day, it should be safe. If expected to be shaded next year by new growth, bark can be protected temporarily with duct tape or stapled cardboard, or even foliated bits of the limb that broke, tied over the bark. Light colored paint is unsightly, but can be applied to reflect sunlight from bark that is expected to remain exposed permanently.

Excessive weight is not only a problem for fruit trees. Some sweetgum, fruitless mulberry and old fashioned Chinese elm trees can produce so much healthy foliage that limbs hang lower than they should. Some shade trees can even drop limbs ‘very’ unexpectedly, when the weather is warm and humid, but without wind.

Shearing Can Not Fix Everything

Shearing enhances foliar density without bloom.

Mowers are for mowing lawns and shallow ground cover. Blowers are for blowing debris from pavement, decking and other flat surfaces. The names of these tools suggest these particular functions. Those of us who use such tools tend to be aware of their limitations. Why are simple concepts of shearing and the associated tools so difficult to understand? 

‘Mow, blow and go’ gardeners are not so bad if they simply mow, blow and go. They tend to the two most significant but also least pleasurable tasks in the garden, and then leave before causing problems. Most are also qualified to add bedding plants or shear hedges. However, some will shear anything that is within reach of their powered hedge trimmers.  

Shearing is for hedges or shrubbery that is strictly foliar. There are few exceptions. Such shearing should be performed properly, and only for the few plants that are conducive to it. The process promotes foliar density, but also generally inhibits bloom. For hedges that function as living fences in the background of more interesting plants, this is no problem.

Otherwise, shearing plants that are not conducive to it ruins appealing form, and inhibits or prevents appealing bloom. Privet and photinia perform well as shorn hedges because their dense evergreen foliage is their primary asset. Their bloom is actually undesirable. Their natural forms are unremarkable, but their shorn forms can be remarkably practical.

Frequent or untimely shearing prevents lemon bottlebrush and oleander from blooming. However, shearing immediately after a bloom phase stimulates new growth to bloom for a subsequent phase. New growth only needs an opportunity to mature and bloom before removal. Such potentially blooming stems need extra space to extend prior to blooming.

As practical as it is for hedges, shearing ruins the foliar texture of other plants. Heavenly bamboo is worthlessly shabby without its naturally intricate foliar texture. Juniper retains good color, but becomes boringly plain. Rhododendron and hibiscus become disfigured and can not bloom. Each of these plants and all others are discriminating about pruning. Few are agreeable to shearing.

There Are Rules To Hedging

Few plants are conducive to shearing

All the wrong plants get shorn. Mow, blow and go gardeners are known for shearing everything that they can reach into creepy and unnaturally geometric shapes, usually flared out at the top, and bulging obtrusively into otherwise usable space. Yet, functional formally shorn hedges are passe and almost never shorn properly.

First of all, a formal hedge should be uniform, which means that all the plants that comprise it should be the same, and planted at the same distance from each other. Any plants within a formal hedge that die should be replaced with the same plant. A single English boxwood plant added to a Japanese boxwood hedge will always stand out with a different shade of green and growth pattern. Seedlings of other plants that grow up into a hedge should be removed before they become part of it.

Secondly, a formal hedge should be contained within defined boundaries. It should get neither too tall, nor too deep (from front to back). A fat hedge wastes space. There is no excuse for a hedge to encroach obtrusively over walkways, driveways or patios.

The vertical faces of a hedge should be completely vertical or slope very slightly inward at the top, but should certainly not slope outward to shade lower growth. A slight inward slope is more important on a northern face of plants that are sensitive to shade.

Hand pruning hedges (with hand shears) produces the best finish, but takes quite a bit of time for big hedges. Shearing with typical hedge shears cuts leaves as well as stems, so can cause foliage with large leaves to look a bit tattered for a while. Hedges that grow fast may need to be shorn twice or more annually. Some hedges can get shorn back aggressively once annually, and then allowed to fluff out evenly through the rest of the year. Bottlebrush and escallonia hedges can bloom nicely and evenly if shorn only once annually.

Glossy and wax leaf privet are among the most traditional of formal hedges. Glossy privet can get quite tall, but wax leaf privet actually has glossier foliage. Photinia and shiny xylosma have a bit more color, but want a bit more space (from front to back). Boxwoods make very nice small hedges. Pittosporums are available in various shapes and sizes. Pittosporum eugenioides gets quite tall, and can be kept quite lean. Pittosporum tobira is shorter and wider.

The Spring Rush Is On

Pittosporum can be pruned aggressively now.

It is safe to say that any remaining frost damage can be pruned away. Frosted foliage and stems were only left through winter to help insulate inner stems from more damage by subsequent frost, and to avoid stimulating new growth that would be even more sensitive to frost. Now that there is no threat of subsequent frost, and surviving but damaged plants are growing anyway, there is no reason to retain unsightly frosted foliage. The few plants that do not regenerate probably did not survive.

Spring is the busiest time of year for most plants. By now, most have either bloomed or will be blooming soon. Early spring bulbs have already finished. Later bulbs will be blooming soon enough. Deciduous plants that were bare through winter are developing new foliage. Evergreen plants are likewise growing new foliage to replace older foliage that will get shed later in the year.

If necessary, flowering cherry, flowering crabapple, lilac, forsythia and mock orange (Philadelphus) can be pruned as they finish bloom. Flowering cherry should not need much; but flowering crabapple might be in need of aggressive structural pruning. Some of the older canes of lilac, forsythia and mock orange can be pruned to the ground, where their replacement canes are probably already emerging.

Overgrown or disfigured oleander, photinia, bottlebrush, privet, pittosporum and juniper that need restorative pruning can be pruned now. They recover most efficiently in early spring, and have plenty of time to develop plenty of new growth before they slow down again next autumn. If pruned much earlier, they would have stayed bare longer, since they would not have grown much through winter. Besides, almost all pittosporum are susceptible to disease if fresh pruning wounds are exposed to rainy weather.

Seed can be sown for any of the warm season vegetables and flowering annuals, such as zucchini, corn, okra, nasturtium, lupine and sunflower. Tomato, pepper, eggplant, petunia, marigold and busy Lizzie (Impatiens) can likewise be grown from seed, but are easier to grow from small cell pack plants. Cuttings of jade plant, iceplant, sedum and all sorts of succulents, as well as divided pups of aloe, agave and yucca, really get going well this time of year.

Start Young Trees Off Right

Recovery is difficult for abused trees.

Young trees are so impressionable. Too much water can damage their roots, or cause them to disperse too shallowly. Improper pruning can disfigure their branch structure, and ultimately compromise structural integrity. Improper staking to keep them stable can actually interfere with development of stabilizing roots, and interfere with trunk development.

Newly planted trees will of course want to be watered from spring to autumn for at least the first year, and more likely for a few years. Those that will eventually be less reliant on watering as they mature are actually the most demanding while young, because their confined roots are not yet adequately dispersed for self sufficiency. The problem is that too much water can keep lower soil too saturated for new roots to disperse into. This causes roots to instead disperse closer to the surface of the soil, which is not only unhealthy for the trees, but puts the roots closer to pavement, other plants and any other features that they can eventually damage as they grow.

Many young trees should be pruned as they grow to eliminate structural problems, and to instead promote good branch structure. The problem is that improper pruning can actually cause structural problems that will be with the victimized trees for the rest of their lives. Pruning should leave no stubs that will take longer to compartmentalize (heal), or that might produce vigorous but weakly attached new stems.

Stakes are unfortunately necessary to stabilize new trees. The problem is that the trees can become so reliant on stakes for support that they do not develop enough trunk strength to support their canopy without stakes. That is why trees should be tied loosely enough to their stakes to be able to move at least a little in a breeze. Nursery stakes (that trees are bound to for a straight trunk in the nursery) should be removed when sturdier stakes are added.

New trees are naturally a bit more distressed than mature trees that have settled into their environment. They are consequently more susceptible to disease and insect infestation.

Spring Pruning Of Flowering Trees

Some plants prefer pruning after bloom.

Most major pruning happens while the plants that need it are dormant through winter. That is why it is known as ‘dormant pruning’. Such pruning would be so much more disruptive while plants are blooming, fruiting, foliating or growing. Pruning that happens during other seasons is not as aggressive as dormant pruning. Spring pruning, although practical for some plants, is relatively docile.

For deciduous fruit trees, dormant pruning is very important. It concentrates resources into fruit production, but also limits production to sustainable quantities. Otherwise, such fruit trees would be unable to support the weight of their own copious fruit. Spring pruning of such trees is simply too late. By that time, superfluous fruit has already consumed significant resources, only to be wasted.

Stone fruit trees and pome fruit trees are familiar examples of deciduous fruit trees that rely on dormant pruning. Stone fruits include peach, nectarine, apricot, plum and their relatives. Pome fruits are primarily apple and pear. Ironically though, their fruitless but flowering counterparts perform best with spring pruning instead. As similar as they all are, they have completely different priorities.

Flowering cherry trees bloom more spectacularly than fruiting cherry trees, but produce no fruit. Similarly, flowering crabapple trees bloom more colorfully than fruiting apple trees, but produce only tiny fruit. Neither must sustain production of significant fruit. Nor must they support the increasing weight of developing fruit. Prolific bloom is their primary function. Spring pruning accommodates.

Spring pruning allows flowering trees to first bloom as profusely as possible. Pruned out stems have already served their purpose. Because fruit production is not a concern, spring pruning is less severe than dormant pruning. Nonetheless, because dormant pruning is so practical for so many plants, spring pruning may seem impractical. It is tempting to prune dormant flowering trees now. Doing so harmlessly compromises bloom.

Blossoms Bloom Sooner If Forced

Stems of tiny blossoms really impress.

Pussywillow is an odd cut flower. It is neither fragrant nor very colorful. It just gets cut and brought into the home because the distinctively fuzzy catkins are so interesting. They are appealing alone or mixed with other late winter flowers. The otherwise bares stems can get cut just as soon as the fuzz is beginning to become visible within the swelling buds. Bloom accelerates once the cut stems are brought into a warm home.

There are actually several other plants that can provide bare twigs that can be ‘forced’ into bloom in the home. ‘Forcing’ is simply the acceleration of bloom of such twigs by cutting them and bringing them from cool winter weather into warm interior ‘weather’. Flowering quince, flowering cherry and flowering (purple leaf) plum have likely finished bloom; but forsythia, hawthorn, flowering crabapple and many of the various fruit trees that have colorful bloom will be ready to be forced any time. Some daring people even force redbud, dogwood, witch hazel, lilac and star and saucer magnolias.

When the deciduous fruit trees that bloom well need to be pruned in winter, some people intentionally leave a few spare branches to be cut and forced later, just before bloom. These include almond, cherry, apricot, plum, prune, nectarine, peach, pear, apple and a few others. When stems get cut for forcing, they should be pruned out from the trees according to proper dormant pruning techniques, and can be trimmed up accordingly when brought into the home. Flowering (non-fruiting) trees should likewise be treated with respect when stems for forcing get pruned out.

Twigs to be forced should be cut just as the flowers are about to bloom, and preferably, as a few flowers are already blooming. They should be put in water immediately, and if possible, cut again with the cut ends submerged. Buds that will be submerged when the stems are fitted into a vase should be removed.

Once in a warm home, the rate of bloom will be accelerated, although everything blooms at a particular rate. Apple and pear bloom later than most, and can bloom slow enough to justify cutting stems while already blooming. As forced stems bloom, they can be quite messy, but the mess is probably worth it.

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.

Some Shrubs Are Better Trees

Sculptural trunks are worth showing off.

So many really nifty small trees never get an opportunity to perform to their best potential. Many function so well as shrubbery that there is no need to prune them into tree form. Many just get shorn down because that is the most obvious option.

There certainly is no problem with maintaining large shrubbery as shrubbery if that is the intended function. Oleander, photinia, privet, bottlebrush and various pittosporums are all excellent shrubbery, and except for oleander, can be shorn into hedges. Yet, any of them can alternatively be grown into small trees.

‘Standards’ are shrubs that are trained onto single staked trunks. Small shrubs trained as standards, such as boxwood, azalea and euryops, are really only shrubbery on a stick. The larger shrubs though, are more often trained onto trunks about six feet tall so that they can develop as small trees with single trunks.

However, they do not necessarily need single straight trunks. Many have naturally sculptural trunks that are worthy of display. They can be planted as shrubbery, and simply trained up on a few of the trunks that they are naturally equipped with. They only need lower growth pruned away as they mature, instead of getting pruned down.

Overgrown shrubbery that has become so obtrusive that it might otherwise need to be removed can often be salvaged by getting pruned up as small trees. For example, if a New Zealand tea tree or myoporum has gotten so wide at the base that it is awkward to work around, the basal growth can be pruned away so that only upper grown that has adequate clearance remains suspended on exposed trunks. The gnarly trunks within are often more appealing than the abused foliage that obscured them.

Japanese maple, crape myrtle, water gum (Tristania laurina) and various podocarpus really are small trees, but often get shorn instead of pruned properly by ‘mow, blow and go’ gardeners who do not know any better. Olive, coast live oak and saucer magnolia are substantial trees that often get shorn into shrubbery before they can grow beyond the reach of abusive gardeners.

Hollywood juniper as well as some of the other larger junipers naturally develop into sculptural small trees that are just as appealing with or without their lower growth. The gnarly foliated stems are just as sculptural as the trunks and stems within. If space allows, they can be left to grow somewhat wildly with only occasional pruning of superfluous stems.

Knowing When To Prune What

Flowering plum trees can be pruned later, after bloom.

Maybe the weather took the surprise out of camellias this year. It has been so warm and pleasant that such big and colorful flowers are almost expected. Even if crocuses and narcissus did not bloom much too early, they are likely finishing a bit early because of the warmth and minimal humidity. Daffodils are not far behind. Hopefully, lilies and tulips will not be too confused. Pansies, primroses, stock, Icelandpoppies, ornamental cabbages and kales actually seem to enjoy the odd weather.

It was such a rush to prune everything that needs to be pruned in winter! Roses are already being outfitted with new foliage. Plum trees are already blooming, and will be followed by apricots, cherries, peaches and the rest. It was actually easy to get carried away, and prune things that should not yet be pruned.

Many of the flowering trees that are related to fruiting trees seem like they should be pruned. However, the rules are different, since they do not need to support the weight of fruit. Pruning only compromises bloom. Flowering cherries, flowering (purple leaf) plums and shrubby flowering quinces should instead be pruned after bloom finishes, and only if necessary. As flowering crabapples finish bloom, minor pruning probably will be necessary.

Lilacs, forsythias and spireas should be pruned by ‘alternating canes’, which means that older canes get cut to the ground as they get replaced by new canes. If done just after bloom, new canes develop through the following summer, and will be ready to bloom the following spring.

Quite a few trees, shrubs and vines likewise want specialized treatment. Fat flower buds of deciduous magnolias make it obvious that pruning should be delayed. Azaleas should probably make their intentions to bloom more obvious. Hydrangeas can be groomed of deteriorated flowers and dead stems, but plump canes from last year will bloom this year. Maples, birches and elms will continue to bleed if pruned now, so should wait for summer.