Black Locust

White black locust bloom seems oxymoronic.

The natural ranges of black locust, Robinia pseudoacacia, likely included only the Ozark Mountains, the Ouachita Mountains, and the Appalachian Mountains south of New York. Early American colonists planted it elsewhere before botanists documented its origins. It was notably used for firewood, durable lumber, erosion mitigation, and soil conditioning.

Modern cultivars are less useful for such applications, but are more appropriate for home gardens. Regardless of elegantly lofty form, delightfully finely textured foliage, and richly fragrant white bloom, the species is aggressively invasive and wickedly thorny. Cultivars can bloom pink or rosy pink, lack thorns, and develop more compact and shapely forms.

Bloom resembles that of wisteria, with many small flowers hanging in pendulous trusses. Deciduous foliage, which was absent through winter, appears in conjunction with bloom, but does not obscure it. Individual leaves are pinnately compound, with small leaflets on central rachises (stalks). Most modern cultivars will not get much more than forty feet tall, to make moderate shade.

Limb Failure Of Spontaneous Nature

Riparian trees notoriously shed limbs spontaneously.

Winter storms sometimes break limbs or topple trees. Such damage is no surprise during winter because that is when almost all windy weather happens here. Early storms during autumn might be more damaging because deciduous trees are less aerodynamic prior to defoliation. Nonetheless, falling trees and limb failure are typically associated with wind.

That is why spontaneous limb failure is such a surprise when it happens, typically during pleasantly mild or warm weather of spring or early summer. It is more likely without wind than with it. Humidity, although atypical here, is a contributing factor. Healthy trees within riparian situations or lawns are more susceptible than distressed trees in drier situations. 

Particular types of trees are more susceptible to spontaneous limb failure as well. Valley oak, coast live oak, sweetgum, carob, some pines and various eucalypti may shed limbs after an unusually rainy winter or an increase of irrigation. Riparian trees, such as willow, cottonwood, box elder and sycamore are notorious for shedding big limbs unexpectedly.

Spontaneous limb failure occurs if limbs are unable to support their own increasing foliar weight. Bloom can add significant weight too. Warmth promotes the vascular activity that increases foliar weight. Humidity and insufficient air circulation inhibit evapotranspiration (evaporation of foliar moisture), which typically compensates for increasing foliar weight.

As the terminology implies, spontaneous limb failure occurs suddenly, and often without warning. It is therefore potentially very dangerous. It is common among limbs that exhibit no prior structural deficiency. Even experienced and educated arborists who are familiar with vulnerable tree species can not identify and mitigate all potentially hazardous limbs. 

Arborists often suggest pruning to limit the weight of trees that are innately susceptible to spontaneous limb failure. However, limbs that are already sagging from their own weight are risky to engage. Most damage occurs in spring and early summer. Fruit trees that are too productive can succumb to the weight of fruit as it ripens through summer or autumn.

Steven Michael Ralls Memorial Tree Update

Felton League, which is my other blog about the Homeless Community of Felton in California, has been severely neglected since last summer, and will unfortunately continue to be neglected for quite a while until I am able to resume writing, which should coincide with the resumption of writing new articles for this blog here. This reblogged post from Felton League is the first new post I took the time to write for a very long time. It is shared here because it is somewhat relevant to horticulture.

tonytomeo's avatarFelton League

Steven Michael Ralls Memorial Tree – May 2, 2021

The Steven Michael Ralls Memorial Tree has done well since it was installed precisely a year ago, on the second of May of 2020, which was the third anniversary of the passing of Steven Michael Ralls.

Although it was installed after the primary rainy season, it enjoyed a few late rain showers prior to requiring supplemental irrigation through summer. It was occasionally given a bit of fertilizer to help it get established. Staking was not necessary.

The young tree may not seem to be much larger now than it was a year ago, but has undoubtedly dispersed roots sufficiently to survive without supplemental irrigation. It may receive a few more doses of fertilizer in conjunction with occasional supplemental irrigation, just to accelerate growth while it is still young and vulnerable, but should not get so much that it becomes reliant on…

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Foliage Is Not Always The Answer

This old article describes how horticulture can not fix everything.

tonytomeo's avatarTony Tomeo

P80414KFoliar tapestries are impressive in the right situation. https://tonytomeo.wordpress.com/2018/02/25/foliar-tapestries/ They work as nicely on exterior walls as conventional tapestries or paintings might work on interior walls. However, they require much more maintenance!

Trendy green walls are overrated. Their only real advantage is that they are pretty. They are not a ‘real’ solution to anything. They may keep the interior of a small building a bit cooler, but no more than light colored paint or a shade structure would. They do not save water, and actually use more water than plants grown in the ground. All that water is likely to rot the walls behind, or the decking below. They do nothing for melting glaciers or saving the planet. In a few more years, when they are no longer trendy, they will be more junk in the landfills.

Most obtrusive exterior walls can be obscured or partly obscured with less demanding…

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Dingo

Since this article posted three years ago, I have been trying to grow copies of Schwedler maple from cutting, as well as grafting onto Norway maple seedlings. Supposedly, it is true to type from seed. I have known the tree since 1976, but have never seen a seedling grow from it. Nor would I trust such a seedling to be true to type.

tonytomeo's avatarTony Tomeo

P80407KDogs and humans have been in a symbiotic relationship longer than history can document. Dogs naturally became more domesticated as humans did, and have been more or less selectively bred for a few thousand years.

Dingos are different. No one knows for certain how domesticated they were when they first came to Australia. They probably had been domesticated enough to come on boats with the first humans to migrate to Australia. After arriving in Australia, they became feral, although still symbiotically migrating with humans. They are now considered a native species of Australia.

Many species of plants have lived symbiotically with humans as well. As long as humans have been living with dogs, they have been domesticating and breeding plants. As plants were more extensively bred, they became more dependent on humans for their perpetuation. Some are so overly bred that they are sterile and unable to perpetuate without human…

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Six on Saturday: Weeds +

Working inside for most of the week has certain disadvantages, especially at this time of year. There is so much blooming that I do not go out to see. I did not get many pictures of camellias or flowering cherries while they bloomed, although some camellias continue to bloom sporadically. Some azaleas are also finished blooming. Rhododendrons are blooming nicely now, but I have not started getting pictures of them. Instead, I got pictures of a few weeds and their associates from just outside of where I work inside.

1. Broom! It is one of the most aggressively invasive exotic weeds of the Santa Cruz Mountains. No one knows if it is Scotch, Spanish or French. It is probably French, but we know it as Scotch.

2. Dandelion infests most lawns. It was probably imported for greens. I will not eat greens that grow in lawns where Rhody does what he goes outside to do. I should move some to the garden.

3. Periwinkle is a naturalized exotic species here, but is not so naturalized farther inland, or in urban areas where lacks space to migrate. I actually planted it where I lived while in high school.

4. Forget me not, as seen in the upper right corner of the previous picture, is naturalized in riparian situations, but is also too delightful to be perceived as a weed. How could anyone dislike it?

5. Pacific Coast iris is not actually a weed. It is not even exotic. This one is a hybrid of a few native species, and was planted intentionally. I would just prefer the ‘unimproved’ Iris douglasiana.

6. Rhody puts the ‘+’ in ‘Weeds +’, which is the title for this week. Perhaps this should have been the first of these six; but then no one would have bothered with the remaining five. Priorities.

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/

Peony

Peonies are unusually happy this year.

The fact that peonies do not perform well in such mild climates does not dissuade some of us from growing them. After all, they can sometimes be found in local nurseries and even farmers’ markets as if they belong here. Tubers of more of the countless varieties can be purchased online or from mail order catalogs while dormant in autumn. Unfortunately, without much winter chill, few peonies perform as they should.

Peonies can be white or various shades of pink or red, with considerable variation of flower structure. Tree peonies that bloom yellow are the most likely to be wimpy without winter chill. All peonies are good cut flowers. After spring bloom, the distinctively coarse and rich green foliage stays until autumn dormancy. The more popular herbaceous peonies should not get more than three feet tall and broad. Tree peonies do not actually grow into trees, but develop woody stems that can hold flowers nearly six feet high. Larger flowers may need support.

Because plants get established so slowly, they should not be moved or disturbed. Small new plants can be divided from larger plants while dormant, but take a few years to actually bloom. Peonies like rich soil and regular watering, where they do not get crowded or shaded by other plants.

Cold Winters Have Certain Advantages

Winter frost can improve spring bloom.

Even in May, damage from the frosts of last winter is still evident among some of the more sensitive plants. Lemon trees and bougainvilleas that have not yet been pruned may still display bare stems protruding above fresher new growth. Some bougainvilleas did not survive. Those that are recovering will bloom later because replacement of foliage is their priority for now.

However, peonies, although rare, are blooming better than they have since 1991, right after one of the worst frosts in recorded history. Earlier, some lilacs, forsythias and wisterias likewise bloomed unusually well. While so many plants were succumbing to cold weather, many others were enjoying it.

The reason that peonies typically do not seem as happy locally as they are in severe climates is that they really prefer more cold weather while they are dormant through winter. Without it, they may not go completely dormant, or may not stay dormant long enough to get the rest that they need; and then wake up tired in spring. Cold winter weather promotes more adequate dormancy, which stimulates healthier growth and bloom this time of year. It all makes sense considering that peonies are naturally endemic to colder climates.

A preference for cooler winter weather is also why so many varieties of apples and pears that are grown in other regions do not perform well here. The good news is that as the fruit of local apple and pear trees matures through spring and summer, it may be of better quality that it has been for many years. Trees that typically produce sparsely may produce more abundantly this year. The weather that damaged tropical and subtropical plants was an advantage to others.

Nothing can restore cherries, apricots, peaches and any other early blooming fruit that was dislodged by late rain, but any fruit that survived may be just as unusually good as apples and pears. Not only is the best place for gardening, but minor weather problems can have certain advantages.

Location – Location -Location!

Yup; this recycled article, unlike others of the past few weeks, actually does conform to the ‘horriduclture’ meme for Wednesday, even if just accidentally. Since this article posted three years ago, the subject palm has grown almost above the adjacent sign. The trunk, although obtrusive, remains.

tonytomeo's avatarTony Tomeo

P80422Speaking of which, this is not the right location!

This unhappy Mexican fan palm may have grown here from seed, as they often do. They are notorious for growing under utility cables because that is where birds drop so many of their seed. Perhaps the seed for this one was dropped by a bird perched on the sign many years ago.

Ironic, isn’t it. Birds tend to perch on utility cables and signs and in trees and everywhere that palms should not be planted. How often do they drop seeds out in the open, where whey will not encroach into something as they grow up? Why can’t they drop palm seeds in places where palm trees would actually be an asset? It happens sometimes, but not as often as palms appear where they are not wanted.

The picture below shows three larger Mexican fan palms that were intentionally planted in…

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Periwinkle

Periwinkle is pretty for a weed.

Dwarf periwinkle, which is a vigorous but manageable ground-cover here, is an invasive weed in other regions. Locally, common periwinkle, Vinca major, is the more aggressive sort. It naturalizes in riparian situations and damp parts of unrefined landscapes. Stolons can be difficult to pull completely from the soil. Seed disperses secretively but efficiently.

Periwinkle is almost never available in nurseries nowadays. It tends to infest gardens by sneaking in. Then, the foliage and bloom can be too appealing to eradicate. More plants are easy to divide from established colonies. Growth is tidier if mown at the end of winter. As it regenerates, it gets more relaxed, and finally gets floppy. It looks shabby if trampled. 

Periwinkle blooms with sporadic but delightfully clear blue bloom. Individual flowers are about an inch and a half wide. The evergreen leaves are an inch or two long. Wiry stems get a foot or two deep. Cultivars with white or purplish blue bloom were available before  

periwinkle naturalized. Periwinkle with foliar variegation still inhabits some old gardens. It is slightly more complaisant.