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Things Heat Up In Summer

70705thumbThis does not seem like such a mild climate when it is difficult to distinguish between the time and the temperature on a local bank clock tower. You know; when punctuation is the only difference between four minutes past one, and one hundred four degrees. Fortunately, like mild frost in winter, hot weather does not happen too often, which is why this climate really is milder than most.

Most of us know what to do for the garden when the weather gets warmer. Obviously, many plants want more water. What we do not often consider is that there a few things that we should ‘not’ do. Unlike us, the plants in the garden can not find shade when the weather gets warm. Those that are exposed find creative ways to provide their own shade. We really do not want to mess with that.

By this time of year, outer foliage of exposed plants is mature enough to tolerate heat. Only foliage of plants that prefer to be partly shaded is likely to be damaged. However, inner foliage of even the toughest plants is not as resilient as outer foliage is. Simply shearing a hedge exposes inner foliage that can be scorched by overexposure. Sunlight enhances the effects of heat and aridity.

If possible, it is best to delay such pruning and shearing until after unusually hot weather. No one wants to be out working in the garden on a hot day anyway. More typical seasonable weather may not seem to be much cooler, but a few degrees can be a big difference to plants. Once exposed, inner foliage should adapt, and hopefully be resilient to heat before the weather gets hot again.

While young and thin, formerly shaded bark that suddenly becomes exposed can be damaged by sun scald. (Deciduous trees do not get scalded while defoliated in winter because the intensity of sunlight is diminished at that time of year.) Sun scald of bark is much more serious than foliar scorch because it kills bark, leaving open wounds on main limbs and trunks. Decay within these wounds compromises structural integrity, and can ruin otherwise healthy trees.

Although rare, spontaneous limb failure can occur in some trees during warm weather, particularly if humidity increases and breezes remain minimal. It sounds silly, but warmth accelerates vascular activity, possibly until foliage becomes too heavy for the limbs that support it. If limbs break, they can cause major disfigurement, and detrimentally expose bark of inner limbs and trunks.

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Horridculture – Mutants


P80704Mutants are the source of many of our favorite cultivars of otherwise simpler specie. Many cultivars of plants with compact, pendulous or fastigiate (strictly vertical) growth, or variegated, bronzed, golden or otherwise abnormally colored foliage, were derived from ‘sports’, which are mutant stems that appear on otherwise normal plants. Thornless blackberries were sports of thorny cultivars. Fruitless mulberry is a sport of white mulberry. There is no shortage of mutants.

https://tonytomeo.wordpress.com/2018/05/07/cultivars-are-the-real-cloned-mutants/

https://tonytomeo.wordpress.com/2018/05/06/sport/

By nature, mutants are genetically unstable. A few can easily mutate back to their original and more genetically stable characteristics. Variegated plants are notorious for developing simple green unvariegated foliage. Because it has more chlorophyll, the unvariegated foliage grows faster, and has the potential to eventually overwhelm and replace the variegated foliage. That is why green sports should get pruned out of variegated plants.

‘President Roosevelt’ is the most popular of the few variegated rhododendrons. In nursery production, it gets pruned somewhat regularly to remove green sports. Variegated specimens are rare in landscapes because almost all revert to unvariegated foliage within only a few years.

‘Yellow Wave’ is a cultivar of New Zealand flax with pendulous yellow striped foliage. It can be seen in front of the upright greener foliage in the background. These are not two separate plants stuck together. The more vigorous green foliage is a reverting sport that should have been removed by the ‘gardener’ who is supposed to be ‘maintaining’ this landscape. The green sport is now so developed that it can not be removed without damaging the rest of the ‘Yellow Wave’ growth. It will undoubtedly be left to overwhelm and replace it. Fortunately, the upright green foliage is about as appealing as the ‘Yellow Wave’, so no one will notice the inadequacy of the maintenance. No one ever does.

Posted on by tonytomeo · 12 Comments

Hydrangea

80711There are so many more of the fancier cultivars of hydrangea, Hydrangea macrophylla, than there were as recently as the 1990s. Many of the pink and blue hydrangeas were interchangeable years ago. They would bloom blue if the soil was acidic. They would bloom pink if the soil was alkaline. Their color changed accordingly when planted from potting media into soil of another pH.

Most of the modern cultivars nowadays are better at one color or the other. Those that want to be rich pink or almost red might turn lavender or purple in acidic soil. Those that want to be rich blue might do the same in alkaline soil. That makes for many hues of pink, blue, lavender and purple. Most of those that bloom white always bloom white, and their foliage might be a little lighter green.

There is also much more variety in floral form than ever before, although all bloom in summer or autumn with big rounded or nearly spherical trusses of many small flowers. The deciduous leaves are about six inches long, and pleasantly lush and glossy. Modern compact cultivars stay low and dense. Larger cultivars get about six feet high and wide, with somewhat open branch structure.

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pH Has Ups And Downs

80711thumbEnvironment is what determines what plants grow where. It may sound simple enough, but environment is a combination of many different factors, including but not limited to climate, soil quality and exposure. Each of these factors is a complicated combination of other factors. For example, climate includes temperature, humidity, rainfall, frost dates, winter chill duration, wind and so on.

Home gardening, like the production of horticultural and agricultural commodities, is obviously limited by environment. Plants that want rich soil with good moisture retention are not happy in clay or inert sandy soils. Annual vegetable and flower plants that do not tolerate frost are grown after the last frost, and finish before the first frost. Annual plants that survive frost are grown in between.

Environmental modifications, such as irrigation, fertilizers and other soil amendments, make it possible to grow what would not normally grow in particular environments. However, environmental modifications are not always practical. For example, if the cost of irrigation of a particular commodity might exceed the projected revenue of that crop, an alternative crop must be grown instead.

pH (the ‘power of hydrogen’) is another one of the many limiting environmental factors. It is what makes the soil acidic or alkaline. Some plants prefer the soil to be slightly acidic with low pH. Some are more tolerant of slight alkalinity with high pH. What we choose to grow in our gardens should be adaptable to the pH of the endemic soil, whether it is acidic, alkaline or close to neutral.

There are all sorts of fertilizers and soil amendments that can modify the pH somewhat if necessary. Such amendments make it possible to grow rhododendrons and azaleas and other plants that prefer slightly acidic soil where the soil is naturally slightly alkaline. The problem is that the adjustments of pH are not permanent, so must be maintained. In many situation, major modification of pH is impractical. It is generally more practical to select plants that will be happy with the natural endemic pH.

Posted on by tonytomeo · 21 Comments

Spontaneous Limb Failure

P80701It is as scary as it sounds. Well foliated limbs or entire trees really do fall spontaneously during the calmest of warm weather. It never fails to frighten anyone who witnesses it. Those who witness it always express the same difficulty with trying to explain it to those who did not witness it, as if they know that no one will believe them.

Several people heard this cottonwood limb fall onto a bridle path in Felton Covered Bridge Park. It is not a particularly large limb. The diameter about a foot above the flared union is only about seven inches.P80701+

Yet, even this relatively small limb is seriously dangerous when it falls from above, and from such a height.P80701++

A much larger sycamore limb that was almost two feet in diameter fell nearby a few years ago. It was like a full sized tree falling from the sky!

What makes it so frightening is the spontaneity. We expect limbs to break when the wind is blowing. Trees are more likely to fall when the soil is saturated from an abundance of rain. Dynamic weather like wind, rain and snow are expected to be the cause of limb or tree failure. Passive weather like warmth and humidity seem like they should be innocent of causing such damage. Not so.

Warmth accelerates vascular activity, which increases the weight of healthy foliage.

Humidity inhibits evapotranspiration (evaporation from foliar surfaces) that would otherwise decrease the increasing foliar weight.

Breezes that are normally thought of as a cause of limb failure would actually enhance evapotranspiration. Therefore, a lack of any breeze actually increases the potential for spontaneous limb failure.

So, while the weather is warm, humid and still, just when you least expect it, spontaneous limb failure is most likely to happen.

Posted on by tonytomeo · 14 Comments

Oasis

P80630KWhat are they doing out there, in those two pots in the island of such a vast parking lot? It is hard to say from this distance. They are so isolated. They might be happy and healthy summer blooming annuals. They might just be weeds. They could be plotting World domination. Plants can do some weird things in isolation.

Mexican fan palm is the most familiar palm in Los Angeles. Some know them as skydusters because they are so tall and lanky, and do not seem to have anything better to do than lazily brush against the undersides of clouds as they float by. In Los Angeles, there are not many clouds to keep them busy, and there is not even much smog anymore. Mexican fan palms certainly do not make much shade, and because they are so tall, their little shadows land in neighbors’ yards. They are so tall that you might be able to see them from wherever you are merely by looking towards Los Angeles. Instead of getting Frisbees and kites stuck in their canopies, they collect satellites. When they drop one of their big leaves, it burns up in the atmosphere.

In their natural environment, Mexican fan palm lives in a large and mostly contiguous native range (areas) in which individual colonies are not isolated for too long. Pollen gets shared rather thoroughly. Trees are consequently very similar throughout the range. Slight genetic variation is only perceptible in regions such as Los Angeles, where various groups of trees are grown from seed collected from various regions of the native range.P80630K+

Sometime in the ancient history of the specie, a few individuals decided to leave the rest of the herd and go live in isolation out in the adjacent deserts. They could only survive where there was a bit of water, so they inhabited any oasis they could find. This might have happened as some trees migrated up canyons that had perennial creeks flowing through them only to have the lower portion of the canyon go dry as outflow from above decreased. Seismic activity within the region has a way of altering the outflow of springs. Anyway, these more reclusive palms eventually became a separate species, or subspecies, or variety, depending on the botanist providing the information. This separate species (or subspecies or variety) is now known as the California fan palm, or the desert fan palm. It thrives on the hot and arid desert air, but is not very happy in milder and more humid coastal climates. (I am sorry that I do not have a good picture at the moment.)

Unlike Mexican fan palm that lives in a big contiguous range, California fan palms lives in small isolated colonies where they can not share their pollen freely with other colonies. Over thousands of years, each colony adapts to its specific environmental conditions. Genetic variation within colonies is not perceptible, but is quite obvious in landscape situations where trees grown from seed from different colonies can be compared.

California fan palm is much shorter and stouter than Mexican fan palm. It does not need to compete with too many other specie out in the desert. The trunks are straighter, and the canopies are fluffier. Unlike the very informal and relaxed Mexican fan palm, it is an excellent palm for formal landscapes. It is the specie that flanks the famous Palm Driveway at the Winchester House in San Jose. The only stipulation for these formal installations is that all the palms must be grown from the same batch of seeds procured from the same colony.

Posted on by tonytomeo · 14 Comments

Six on Saturday: Infrastructure

 

There is so much more to horticulture than plant material. There is a lot of hard work, which is hard to get in pictures. There are a lot of materials. There is a lot in infrastructure.

Well, I do not have pictures from the farm to show how our horticultural commodities are grown. That would not be very interesting anyway. These pictures are merely odds and ends of what we work with in regard to landscape maintenance.

1. Incarcerated stone. Yes, it is quite obvious that this prison is overcrowded. This is where they do ‘hard’ time. Incidentally, ‘Pet Rock’ was invented in Los Gatos.P80630
2. Half barrel. Back when there were more real wineries in the Santa Clara Valley, barrels such as this were cheap, and could sometimes be found left on the sides of roads for anyone who wanted to take them for kindling. At nurseries and lumber yards, they could be purchased already cut in half, perforated with a few drainage holes on the bottom, and painted with wax on the inside, for use as planters. They are more expensive now. This particular barrel came from France, so is not even made of local valley oak. See the fancy label at the top of the picture? The drainage hole on the left was not drilled through because the drill bit encountered something metallic in the wood. Check out the tips of my stylish boots at the bottom of the picture.P80630+
3. ErmitagE France. This metallic label on the wine barrel is so comically contradictory! The lack of an ‘H’ at the beginning, and the capitalized ‘E” at the end of ‘ErmitagE’ implies that the former contents of the barrel was something fancy, but is then followed by ‘France’.P80630++
4. NO DUMPING ALLOWED. This is a classic example of ‘Do as I say, not as I do’. We dump debris from landscape maintenance all the time. When we prune for road clearance, much of the debris gets thrown back out into the forest behind what was pruned. In some spots, it works like mulch to keep some of the weeds down. Larger bits must get taken away of course. This sign will be posted on a wide spot on one of the roadways where dumping had apparently been a problem. By the way, it is just coincidence that the two words ‘CHILD DUMPING’ lined up like that.P80630+++
5. White star magnolia. This was just moved to the new landscape of a newly renovated building. https://tonytomeo.wordpress.com/2018/06/16/six-on-saturday-rock-on/ We would have preferred to wait for it to defoliate in autumn before relocating it, but it was in the way within another recently landscaped area, and we really wanted to install it here in the new landscape before other material gets installed around it. https://tonytomeo.wordpress.com/2018/04/07/six-on-saturday-rock-concert/ It does not seem to know that it has been moved. I happened to grow these along with many other magnolias back in the late 1990s, and really did not like working with them in the nursery. We just were not set up for them. However, I really like them in the landscape. This particular magnolia grows like a large shrub, so will not get big enough to drop flowers onto all that pavement. That would have been a concern with larger magnolia trees that bloom with larger flowers that can be a slipping hazard when they fall onto pavement.P80630++++
6. Epiphyllum. This just happens to be in bloom at the shop. It belongs to the horticulturist who maintains all the landscapes here, so has nothing do do with the landscapes. With all the pictures of inert items and only one white star magnolia, I thought I should include something a bit more colorful. It does not get much more colorful than this.P80630+++++
This is the link for Six on Saturday, for anyone else who would like to participate:

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

Posted on by tonytomeo · 11 Comments

Beech

70628Compared to crape myrtle, sycamore (London plane) and many other more popular trees, the beech, Fagus sylvatica, is much less problematic, and really deserves more respect. Although it can eventually get almost as big as sycamore, it has remarkably complaisant roots. It is neatly deciduous, defoliating only in autumn, without noticeable floral mess. Disease and pests are rare.

Beech is probably unpopular with landscapers because new trees are a bit more demanding than other tree specie are. (Landscapers prefer easier trees.) Until they disperse their roots, they are more likely to desiccate if they do not get watered regularly enough, and more likely to rot if watered too much. They grow somewhat slowly, so need to be pruned more carefully for a high canopy.

Those of us who tend our own gardens do not mind the extra effort for such a distinctive tree. The handsome foliage can be rich green, coppery bronze, darkly purplish or variegated with white or pink that fades to white. A cultivar with sunny yellow new foliage fades to green by summer. Most beeches have spreading branch structure, but some are strictly vertical or sculpturally pendulous.

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Good Roots Are Seldom Seen

70628thumbWhen a tree falls in the forest, and there is no one around to hear it, does it make a sound? Of course it does! There is just no one to hear it. Why should that be such a profound question? A falling tree makes a mess too. Anyone who does not see or hear it in action can witness it afterward. Sometimes, roots that were inadequate to support the fallen tree become exposed as well.

There is certainly nothing unnatural about trees falling in forests. Otherwise, forests would be too crowded for new trees or anything else to inhabit. The roots of fallen trees might have been adequate for many decades or centuries, but eventually succumbed to decay and the weight of the canopies they supported and sustained. Trees falling in home gardens are completely different.

Domestic trees (in home gardens) are likely to land on homes, cars, other plants, or anything that happens to be in their way if they fall. Also, they are more likely to have problems with the roots that support them. Regular irrigation needed to sustain other landscape plants promotes rot, and also inhibits deep root dispersion. Excessive irrigation that keeps soil saturated is much worse!

The good news is that, despite their innate disadvantages, domestic trees tend to be shorter, stouter and more stable. With proper maintenance, they seldom fall; or at least they are more likely to get removed before they fall. Buttressed roots that are visible at the surface of the soil might indicate that deeper root dispersion has been inhibited. The best roots are too deep to be seen.

Whether or not buttressed or shallowly dispersed roots limit stability, they can damage pavement, lawns, septic systems, or other features on the surface of the soil. Subterranean utilities and foundations of modern buildings are typically safe, but on rare occasion, can be damaged by the largest sorts of trees. Root barriers divert roots, but those of big trees eventually get around them. Potentially damaging roots can be severed while young, but become more integral to sustaining and supporting as they grow.

Posted on by tonytomeo · 19 Comments

Horridculture – The Wrong Plant In The Wrong Place

P80627This is the opposite of the ‘right plant in the right place’. It is something that horticultural professionals should neither promote nor tolerate when feral plants appear in landscapes that they are getting payed to maintain. This example looks like it is more relevant to the topic of ‘Fat Hedges’ from https://tonytomeo.wordpress.com/2018/06/06/horridculture-fat-hedges/ , but there is more to this feral pyracantha than that. Yes, it is shorn too frequently to bloom or produce colorful berries. Yes, it looks like an upside-down and halfway buried Christmas tree. Yes, it contributes nothing to the landscape. What is worst of all is that it does not even belong there. It was certainly not planted there on the edge of the curb. There are others nearby, but they happened to appear in spots where they could have actually been assets to the landscape if they had not also been shorn into this weird upside-down and halfway buried Christmas tree shape.

Pulling or at least cutting weeds is generally one of the responsibilities of maintenance ‘gardeners’. It might be acceptable or even preferred to leave a few feral plants if they happen to appear where they might be useful. Those that appear where they would be a problem must be removed. It really would not have been much work to pull this particular pyracantha if it had been done when it first appeared. Even if it had not been pulled right away, and gotten cut down by a weed whacker long enough to develop strongly attached roots, it could have been dug out while young with only a bit of effort.

Okay, so that is in the past now, just like all the other days, weeks, months and years that this feral pyracantha was not removed. Okay, so if for some reason known only the maintenance ‘gardener’ who likely charges significant fees for the maintenance of this landscape, this specimen is to be salvaged, should it not have been pruned back away from the curb? Of course! Although it is right on the curb, much of the growth could have been directed back away from the curb and over the bare embankment. That area is not used for anything anyway. The emptiness of the embankment is certainly no asset to the landscape. Empty pavement is an asset here.

A chain is only as strong as the weakest link. A driveway is only as wide as the narrowest part. All this asphalt pavement and concrete curb is expensive. It was probably worth it to get a nice wide driveway. However, the usable area is not as wide now as it was originally. The feral pyracantha that looks like an upside-down and halfway buried Christmas tree extends nearly four feet into it. That means that the usable space of the expensive driveway is nearly four feet narrower in that spot than it should be. Just think of all the expense that could have been saved if the driveway had been constructed four feet narrower than it had been!