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.

Pruning Roses During Winter Dormancy

Pruning now promotes better bloom later.

Contrary to what the pleasant weather suggests, it is still winter. Most plants are resisting the temptation to break dormancy prematurely. They must know that the days are still short, regardless of the weather. Most plants are surprisingly proficient with scheduling. Nonetheless, dormant pruning should happen sooner than later. This includes pruning roses. They have been ready for a while.

Technically, roses are ready for pruning as soon as they begin to defoliate. Also technically, rose pruning can be as late as the buds of the bare stems remain dormant. Later pruning is preferable in some regions where pruning wounds are susceptible to pathogens. Such delay is riskier here where mild weather can disrupt dormancy prematurely. Wounds are less vulnerable to pathogens.

Pruning roses is about as important as pruning deciduous fruit trees. Without adequate pruning, rose plants become too overgrown to perform properly. Crowded stems are unable to elongate as they should. Diseases and insects proliferate in congested foliage, and damage bloom. Specialized pruning concentrates resources into fewer but significantly more vigorous stems and flowers.

Although the technique may seem to be drastic, pruning roses is not very complicated. Hybrid tea, grandiflora and floribunda roses should retain only three to six of their most vigorous canes. The canes should be only about two feet tall, and cut just above a healthy bud. If possible, they should be canes that grew during the previous year, from bottom to top. Older canes should be removed.

Pruning roses of other classifications may be slightly different. Some types may retain more canes. Climbing types likely retain old canes for several years before replacement. Carpet roses and other ungrafted roses can be cut nearly to the ground, leaving no canes at all. Tree roses are like bush types, but on top of short trunks. New canes grow from their graft unions on top of the trunks.

Of course, potentially vigorous sucker growth that develops from below the graft union of any grafted rose must go.

Six on Saturday: HAPPY NEW YEAR!

2021 was already a popular year before it got started. Many wanted 2020 to end, as if all the unpleasantries of last year would end with it. To me, the first day of this year seemed to be just like any of the few last days of last year. That is not necessarily bad. There was quite a bit of good last year, even with all of the unpleasantries. Many of us see examples of it in our gardens.

Well, these pictures happen to be from yesterday, the first day of January and 2021.

1. Eucalyptus sideroxylon, red ironbark, is the first tree I planted in 2021, on New Year’s Day. It died back last spring, and regenerated with shrubby growth, so got pruned to a single trunk.

2. It should be glad to be out of its can, and into a new home. It originated as a root sucker of a tree that had been cut down. It came up with roots when I pulled it, so could not be discarded.

3. Agave attenuata, foxtail agave, got run over on Pacific Avenue in Santa Cruz. It was not crossing the road, but just minding its own business in a median. I could not leave it there like that.

4. It should be happy here. Adventitious roots are already developing on the trunk. A small section of the base of the trunk was cut off and canned so that new pups could mature separately.

5. Hedychium gardnerianum, Kahili ginger, originated from a neglected landscape near where the red ironbark eucalyptus originated from. Foliage from last year will shrivel through winter.

6. Quercus lobata, valley oak, is the Memorial Tree, and is the first tree that I pruned in 2021. It is developing well. I will return to stabilize the lodgepole stake, and adjust the binding stake.

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

Deciduous Fruit Trees Need Pruning

Prune now for better peaches later.

Many plants should get most of the pruning they need while they are dormant in winter. Such pruning is less stressful because it happens while plants are naturally sedated. Some plants that need aggressive pruning during their winter dormancy may need no other pruning until the following winter. Most deciduous fruit trees conform to this category. Their pruning is rigorous and specialized.

The innately aggressive pruning that deciduous fruit trees require may seem to be brutally unnatural, but is very justifiable. It is necessary to compensate for unnatural production. After centuries of selective breeding, most deciduous fruit trees produce more fruit than they can support. Their fruit is unnaturally abundant, unnaturally bulky, or both. Such improvement has distinct consequences.

Unlike their wild ancestry, many modern deciduous fruit trees would not thrive for long without intervention. The weight of their fruit eventually breaks and disfigures limbs. Such breakage exposes sensitive bark to sun scald, and leaves wounds open to decay. Insect and disease pathogens proliferate in deteriorating growth. Furthermore, messy excess and unreachable fruit attracts vermin.

Pruning improves the structural integrity of deciduous fruit trees so that they can support their fruit. It also concentrates resources into fewer fruits of superior quality, rather than allowing production of inferior surplus. Invigorated vegetative growth is more resilient to pathogens. Proper pruning removes dead, dying, damaged and diseased growth, the ‘four Ds’, as well as unreachable growth.

The main categories of deciduous fruit trees are stone fruits and pomme fruits. Stone fruits are of the genus Prunus. They include peach, nectarine, apricot, plum, prune, cherry, their hybrids, and almond. (Almonds are the ‘stones’ of their fruits.) Pomme fruits are apple, pear and quince. Peaches need more aggressive pruning than cherries, simply because their fruits are so much bigger.

Pomegranate, persimmon and fig also need specialized pruning while dormant through winter.