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Defoliation And Dormancy Are Justifiable

Wind blows freely past defoliated stems.

Defoliation and dormancy begin early for quite a few species within desert and chaparral climates. California buckeye can defoliate during the driest summer weather, refoliate for autumn, and then defoliate again for winter. They do what they must to avoid desiccation within their arid climate. Many more species do what they must to survive through winter.

That is why so many plant species are deciduous while they are dormant through winter. They shed their foliage when it is more likely to be a liability than an asset. Like summer dormant plants, they respond to inevitable and potentially detrimental weather. Moreover, they respond to seasonal changes of sunlight as well. Plant species are very perceptive.

With few exceptions, deciduous plants are nonconiferous or broadleaf species. More are endemic to regions to the north and south of tropical regions than within tropical regions. They know that sunlight is less intense and daylength is shorter while the sun is at a low angle during winter. Their defoliation coincides with the least usefulness for their foliage.

Most deciduous plant species are also aware of the sort of weather that they are likely to encounter during winter. Cold and stormy weather with wind and rain or perhaps snow is probably familiar to them. They know that foliage is not only vulnerable to damage, but is also burdensome to associated stems. In colder climates, it can accumulate heavy snow.

Foliage is the source of almost all wind resistance within foliar canopies that suspend it. Such wind resistance causes wind to dislodge limbs or blow vegetation over, particularly while soil is moist from rain. Defoliation eliminates much of such risk prior to the windiest and therefore riskiest storms of winter. Bare stems are more aerodynamic than foliage is.

Defoliation seems to happen at the best time, immediately prior to wintry weather. It even increases warming sunlight exposure during the darkest and coolest season of the year. However, defoliation is also messy while the weather is unpleasant for those who go out to rake it away. Without prompt raking, it clogs drainage of rain while it is most important.

Posted on by tonytomeo

Winter Is Bare Root Season

Plant a bare root peach tree now for peaches like this later.

Now that nurseries and garden centers are no longer selling Christmas trees, they have plenty of room for bare root stock. All sorts of deciduous fruit trees, a few deciduous shade trees, shrubs and vines, and even a few perennials can now be purchased while dormant and without the cumbersome media (soil) that the roots need at all other times of the year. Not only is bare root stock easier to handle and transport in small cars, but it is also much less expensive than canned stock (that has roots contained in media, which is contained in nursery cans). Bare root stock typically costs about a third of what canned stock costs.

Bare root stock also has the advantage of adapting to new garden easier, since it does not need to leave the comfort zone of the media that it would have grown into (within a can) in order to venture out into unfamiliar soil. Instead, it starts to disperse roots into the new home soil immediately as it emerges from dormancy in late winter. Without cans, bare root stock can not get root bound. Instead of developing branch structure that is appealing to nursery marketing, bare root stock can get an early start on developing branch structure that is most practical and efficient for the gardens that it gets installed into.

It seems that all of the ´stone’ fruit can be found as bare root stock. These include apricot, cherry, plum, prune, peach, nectarine, almond (which is the seed, or ´stone’, of a peach like fruit) and the odd hybrids of these. The pomme fruits, apple, pear and quince, are perhaps the second most popular of bare root stock, although quince is still rather rare. Ornamental trees, shrubs and vines include flowering crabapple, flowering cherry, flowering quince, alder, poplar, willow, lilac, forsythia, wisteria and clematis. Perennials include rhubarb and artichoke.

Bare root stock can be purchased as soon as it becomes available, but does not do much until it starts to grow in spring. It should get planted quickly and soaked in, but will get more water than it needs from rain afterward. It should not need water again until after it blooms or gets new leaves in late winter or early spring. Despite guarantees of fruit in the first year, none should be expected. The few fruit trees that might set fruit will probably produce only useless underdeveloped fruit because new plants are busy producing new roots and growing. Actually though, this apples to canned stock as well, except only for citrus, olives and other evergreen fruit trees.

Posted on by tonytomeo · 3 Comments

Dormant Pruning Enhances Fruit Production

Dormant pruning may not be pretty.

Adding new fruit trees to a garden is reasonably easy. Maintaining them properly as they mature is more of a challenge. Centuries of extensive breeding to enhance production of such trees has also increased their reliance on horticultural intervention. Most deciduous fruit trees consequently need specialized dormant pruning during their winter dormancy.

Without adequate dormant pruning, most deciduous fruit trees are unable to support their unnaturally large and unnaturally abundant fruit. Dormant pruning actually enhances the size and quality of fruit. However, it also limits the weight of excessiveness, and confines it to sturdier branch structure. It concentrates resources into fewer fruit of superior quality.

Dormant pruning, or winter pruning, likewise concentrates resources into more docile but healthier vegetative growth. It eliminates or at least diminishes the 4 Ds, which are dead, diseased, damaged and disfigured growth. Confinement of potentially rampant stems not only improves structural integrity, but also limits wasteful production of unreachable fruit.

Almost all deciduous fruit trees, and most nut trees, require specialized dormant pruning. So do grapevines, kiwi vines, berry canes and roses. Evergreen fruit trees, such as citrus and avocados, are exempt for now though, since such pruning promotes new growth that is vulnerable to frost. Most of such trees do not require such aggressive pruning anyway.

Almonds, apricots, cherries, nectarines, peaches, plums, prunes and all their hybrids are stone fruits of the genus Prunus. Almonds are actually seeds, or stones, of leathery fruits that are merely hulls. Various stone fruits need various degrees of similar pruning. Heavy peaches need aggressive pruning. Lightweight cherries might need only minor trimming, or no pruning at all.

Apples, pears and quinces are pomme fruits that, like stone fruits, need various degrees of similar pruning that conforms to their distinct characteristics. Persimmons, mulberries, pomegranates and figs each need specific types of pruning as well. Familiarity with each of the dormant pruning techniques that each fruit tree in the garden requires is essential.

Posted on by tonytomeo

Live Christmas Trees Eventually Grow Up

Small coniferous trees do not stay small for long.

One of the problems with driving my favorite vehicles that were old long before I learned to drive them is that I spend considerable time waiting for a bus or walking. The cool thing about that is that I get to seem so much scenery that I would otherwise drive past. While waiting nearly an hour for a bus at the Cavallero Bus Terminal in Scott’s Valley, I went across the street to see the landscape of the somewhat new Post Office, which has actually been there for many years now.

The landscape is a bit sparse in front (I think because of architectural modifications after the landscape was designed), so was outfitted with recycled live Christmas trees. Although none of these particular trees seem happy in the local climate or sandy soil, I had wanted to get better acquainted with them for some time. They are an odd assortment of spruce and fir that are rare here.

The more typical concern with the more common live Christmas trees is not that they are not well suited to local climates and soils, but that they actually do too well and grow much larger than expected. Except for the small rosemary, holly and English ivy ‘trees’, most coniferous evergreen live Christmas trees are young pines that get remarkably large; and some waste no time doing it! The most common live Christmas trees are Italian stone pines, which happen to be the two very large and broad trees in Blaney Plaza in downtown Saratoga!

Canary Island pines, which had been more common than they are now, do not get quite as broad, but do get very tall and messy. Years ago, Aleppo, Eldarica and Monterey pines all took their turns being popular live Christmas trees. Each of them grows large enough to require significant garden space.

This is of course not a problem for the few live Christmas trees that happen to get planted where they have plenty of space. However, those that get planted where they do not have room to grow can cause serious problems. Because they seem so cute and innocent while they are young, and are so often expected to stay cute and innocent, many often get planted dangerously close to houses, where they can displace porches, walkways and even foundations! Large pines, particularly Italian stone pines, are also too messy and potentially combustible (if not pruned and groomed regularly) to be too close to houses.

Sadly, large pines do not like to stay in containers too long. They can be pruned for a few years, but eventually get congested roots. (Bonsai techniques of root pruning can maintain even the largest types of pines in containers indefinitely, but not many of us know these techniques.) Small pines, like Austrian black, Japanese black and Scott’s pine (which has no relation to Scott’s Valley), as well as other small coniferous evergreens, like certain junipers, can stay in containers much longer, but these are the sort that are small enough to get planted in the garden, so do not necessarily need to stay in containers anyway.

If space is not sufficient, pines and other live Christmas trees that eventually get too large really should be given to friends and neighbors who have space to accommodate them. Fortunately, most do not require much attention once they get established after two years or so.

Posted on by tonytomeo

Bare-Root Stock Arrives For Winter

Bare roots might fail to impress.

Spring is overrated. It is obviously the best season for planting warm season vegetables and bedding plants. It is the most colorful season with more flowers in bloom. There is so much more to gardening though. Most plants prefer autumn planting. Some prefer winter planting. That is why this present bare-root season will be so relevant all through winter.

Dormancy is an advantage to stressful procedures such as planting. Spring bulbs prefer autumn or early winter planting while they are most dormant. For the same reason and to avoid late frost, summer bulbs prefer later winter planting. It should be no surprise that so many deciduous woody plants likewise prefer dormant planting during bare-root season.

Bare-root season is simply when bare-root stock becomes available for planting through winter. Unlike more familiar canned (potted) stock, bare-root stock lacks the medium that it grew in. Their roots are literally bare. Most bare-root stock awaits purchase at nurseries with its roots resting within damp sand. Roots of some are bagged within damp sawdust.

Bare-root stock is innately more practical than typical canned stock. It is significantly less expensive. It is much less cumbersome, and therefore easier to transport from nurseries. Planting is easier within much smaller planting holes. Formerly bare roots disperse new roots into their garden soils more efficiently than crowded formerly canned root systems.

Deciduous fruit trees and roses are the most popular of bare-root stock. Most of such fruit trees are stone fruits and pomme fruits. Stone fruits include almond, apricot, cherry, plum, prune, peach and nectarine, as well as their unusual hybrids. All stone fruits are species of the genus, Prunus. Pomme fruits include apple, pear, Asian pear and perhaps quince.

Fig, pomegranate and persimmon trees should also be available. So should grapevines, currants, gooseberries, blueberries and various cane berries. Strawberries, rhubarb and asparagus are perennials that are available bare-root. Except for almond, most nut trees, including English walnut, pecan, filbert or chestnut, may be available only by mail order. Most mail order catalogs are online now.

Posted on by tonytomeo · 4 Comments

Arborists Are Physicians Of Trees

This specimen would be a challenge for an arborist.

(This article is recycled from a decade ago.)

Pasadena sustained the worst of the damage caused by the strongest Santa Ana Winds in three decades. Huge piles of debris from broken trees are much more than can be removed any time soon. Falling debris and trees damaged many roofs, cars and anything else that happened to get in the way.

Other towns and neighborhoods throughout the area, particularly those at the base of mountains, also sustained major damage. At the same time, severe winds ravaged the San Francisco and Monterey Bay Areas as well, particularly in the Santa Cruz Mountains and the hills of the East Bay.

Some of the damage caused by wind in urban areas might have been less disastrous if trees had gotten the respect and attention that they deserve. Some trees develop structural deficiencies that need to be corrected by pruning, either to eliminate the problems, or at least to decrease the strain exerted onto the structurally deficient parts. A few trees that become unstable as they mature may likewise need to be pruned or even removed.

It is not always possible to prune trees to remove all structural deficiencies without damaging the affected trees more, or causing more structural problems to develop. For example, major pruning to remove all parts that may get blown down by wind, such as pollarding or ‘topping’, may seem to be effective for the short term, but actually stimulates the development of vigorous secondary growth or watersprouts that are disproportionately heavy and even more likely to tear off from the older limbs.

Structural pruning more often involves thorough reduction of weight and wind resistance. Weight of foliage and stems directly applies leverage against unions where smaller stems are attached to the larger stems from which they originate. Wind resistance adds more leverage as foliage gets blown about by wind. Thinning obviously removes significant weight, and also decreases wind resistance to allow wind to blow though the affected canopies.

Besides helping to compensate for structural deficiency, structural pruning is also beneficial to potentially unstable trees for the same reasons. However, unstable trees typically need even more reduction of weight and wind resistance. Some of the most unstable trees and those that are deteriorating need to be removed because their instability cannot be accommodated.

During winter, while deciduous trees are bare, evergreen trees are more susceptible to wind damage, obviously because they retain their weight and wind resistance through winter while the weather is the most severe. Unstable trees become even more destabilized as rain softens the soil. Regardless of the potential for susceptibility to wind damage, this would be a good time of year to get any needed tree maintenance done, prior to any more windy and rainy winter weather.

Arborists certified by the International Society of Arboriculture are the most qualified to identify potential structural problems or instability, and to prescribe corrective procedures. A list of certified arborists can be found at the website of the International Society of Arboriculture at http://www.isaarbor.com.

Posted on by tonytomeo

Rain Initiates The Rainy Season

Weather generally conforms to the seasons.

Seasons here may seem to be less extreme than they are within other climates. Summer warmth is rarely too hot, and when it is, it does not continue for too long. Winter chill may be insufficient for some plants that rely on it to sustain their winter dormancy. Autumn and spring are as notable for the first and last seasonal rain as for colorful foliage and bloom.

This is actually very relevant within local chaparral climates. Rain and lack of rain define seasons here as much as extremes of temperature. Where the traditional four seasons of winter, spring, summer and autumn merge so softly, the rainy season and the dry season generally do not. Rain begins abruptly in autumn, and ends almost as abruptly in spring.

Consequently, home gardens can get inhospitably dry without adequate irrigation during more than half of the year. Then, they may require no irrigation for almost half of the year. Warm weather that coincides with the dry season enhances aridness. Cool weather that coincides with the rainy season enhances dampness. Mild climates can get extreme too.

Recent rain ended both the dry season and the fire season, and began the rainy season. For many plants, irrigation will be unnecessary until the dry season resumes next spring. Plants that continue to require irrigation will require much less, and only as their soil gets dry during prolonged lapses of rain. Therefore, automated irrigation requires adjustment.

Potted plants, bedding plants and young plants with minimal root dispersion will be more likely to want watering during warm lapses of rain. Substantial foundation plants beneath eaves generally extend roots beyond sheltered soil, but some do not. Also, potted plants under eaves of porches are unable to reach rain moistened soil with their confined roots.

While diminishing the need for irrigation, rain can be messy. It is, of course, wet. It makes soil muddy. Runoff can cause erosion. Stormy weather, which typically involves both rain and wind, dislodges copious foliar debris. Such debris accumulates while no one wants to go outside during stormy weather to rake it. Inconvenient timing seems to be a pattern. Yet, rain is undeniably gratifying.

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Deciduous Trees Are Not Necessarily The Messiest

This weird Euphorbia is one of the few small evergreen trees that drops no foliage.

Contrary to popular belief, most deciduous trees, those that drop all their leaves in autumn, are not as messy as most evergreen trees. There are of course a few exception; such as cacti that lack foliage completely, or Italian cypress that drop their finely textured foliage straight down within a very narrow drip-zone, where it decomposes and disappears unnoticed. Very few leaves fall from a big silver maple through winter, spring and summer, so that almost all of the raking is done when almost all the leaves get shed in autumn. However, a big Southern magnolia generally drops leaves throughout the year, so that raking is always necessary.

The problem is that when deciduous trees get to be messy, they are very messy. Also, they get to be messy at the worst time of year, when their leaves mix with rain to clog drains and gutters. Unraked leaves become hazardously slippery when they get wet and start to decompose. It is amazing how something that can be so appealingly colorful through autumn can so quickly become such a nuisance.

Leaves of deciduous trees somehow seem to be better for composting than those of some of the evergreen trees. Anyone with a Southern magnolia knows how slow the foliage is to decompose. Foliage of camphor, bay, carob and various eucalyptus certainly decompose slower than various maple, ash, poplar and birch. Many of us outfitted with green waste bins or curbside collection of green waste prefer to recycle the less desirable evergreen foliage, and compost primarily deciduous foliage. Those of us who do not compost but need to rake under large or many deciduous trees may fill bins for several weeks, or leave very big piles of leaves at the curb.

Small leaves, such as those of most elms, or finely textured compound leaves, such as those of silk tree, jacaranda or locust, may not need to be raked if they fall onto lower shrubbery or ground cover. Small leaves or the small leaflets of disintegrating compound leaves simply sift through the lower plant material to decompose below. However, large elms may produce such an abundance of foliage that some may need to be removed. Maple and other large leaves are not so easy to ignore. They can shade lawns, ground cover or bedding plants, so need to be raked as they fall.

Posted on by tonytomeo · 4 Comments

Frost Damage Makes Its Appearance

Frost damage of canna looks shabby.

Exotic plants are not native. They are from someplace else. Yet, most plants within most home gardens are exotic. Most are capable of tolerating the more extreme climates from which they originated. Some tropical or subtropical plants actually prefer milder climates. After the recent cool weather, some vulnerable plants exhibit symptoms of frost damage.

Vulnerability is relative though. Honeybush and elderberry can be mostly evergreen with minimal chill, or deciduous with more pronounced chill. Both tolerate more chill than they can experience here. What may seem to be frost damage of specimens that are normally evergreen could be a normal deciduous response to slightly abnormally cooler weather.

Frost damage is also relative. Partial defoliation of Mexican lime might happen annually after minor frost, so may not be alarming. However, such seemingly minor damage could involve stems or entire trees. Luxuriant canna foliage that so instantly becomes unsightly after minor frost can be more alarming. However, dormant rhizomes are safe until spring.

The simplest means to avoid frost damage is to not grow plants that are susceptible to it. Obviously, that is quite limiting. Besides, plants that were not susceptible last winter may be susceptible this winter or sometime in the future. Weather is annually variable. Some susceptible plants can grow in pots that are portable enough to relocate to winter shelter.

Small but immobile plants that are vulnerable to frost damage may appreciate temporary shelter during frosty weather. Any sort of sheeting or cardboard suspended by any sort of stakes and strings should be adequate. Ideally, the sheeting should not touch the foliage below. Incandescent Christmas lights under such sheeting radiate a slight bit of warmth. Frost occurs only at nighttime locally.

Frost protection can be unsightly, but it is less unsightly than frost damage. Fortunately, it is temporary during frost. If not too unsightly, most frost damage should remain until after the last frost date. It insulates other vulnerable vegetation within. Furthermore, premature grooming or pruning stimulates new growth that is more vulnerable to subsequent frosts.

Posted on by tonytomeo · 2 Comments

Grafting fact and fiction

The scion is above this graft union. The rootstock is below.

There are not many Californians of my generation who do not remember growing avocado trees from seeds when we were kids. We simply impaled the big seeds around the middle with three evenly spaced toothpicks to suspend them from the rims of Dixie cups partly full of water. If just the bottoms of these seeds remained properly submerged, they grew roots and a stem with a few leaves, all they needed to grow into trees that were producing too many avocados by the time we got to high school.

Yet, I and others of my generation have always heard that avocado trees need to be grafted to produce fruit. (Grafting is the union of two or more compatible but different plants. The ‘scion’ is the upper portion that forms a trunk, branches and foliage. The ‘rootstock’ is the lower portion that provides roots.) Well, this is obviously not true, but does make us wonder about the advantages of grafted trees.

They myth of seed grown trees being unproductive probably originates from the tendency for seed grown avocado trees to be unproductive for the first few years during the juvenile stage. Scions of grafted trees are taken from adult growth that is ready to bloom and fruit immediately; although even grafted trees need a few years to grow large enough to produce more than just a few avocados.

Many plants are juvenile while young, in order to better compete in the wild. While juvenile, avocado tree seedlings grow vigorously enough to compete with other trees. Adult habits of blooming and fruiting would only slow them down. Besides being fruitless for many years, citrus seedlings are very thorny through their juvenile phase, to avoid getting eaten by grazing animals. Scions of grafted citrus trees are from relatively thornless adult growth that is immediately ready to produce fruit.

The primary advantage of grafting fruit trees though, is keeping the many different cultivars (cultivated varieties) ‘true to type’, since many seed grown plants exhibit at least some degree of genetic variation from their parents. For example, avocados from seed grown (ungrafted) trees tend to be much larger, but often less flavorful than the fruit that the original seed came from. No one really knows what the fruit will be like until it actually develops. Some seed grown peaches are indistinguishable from their parents, but most are very different. However, most pecans and chestnuts are actually produced from ungrafted seed grown trees.

The secondary advantage of grafting fruit trees is the ability to graft onto dwarfing rootstock. Although few avocado trees are dwarf trees, almost all citrus trees for home gardens are grafted onto dwarfing rootstock that keeps them more compact and proportionate to home gardens. Most deciduous fruit trees are similarly grafted onto semi-dwarf rootstock.