Streets Might Benefit From Shade

Proportion is important for street trees.

Shade has become less of a priority for modern urban gardens than it still is for older and more spacious suburban gardens. Significantly less sunlight reaches the ground of such confined gardens among taller and shadier homes and fences. Even where shade might be desirable, space for shade trees might be minimal. Streets are the primary exception.

Streets, and associated curbs and sidewalks, are generally the sunniest situations within modern urban neighborhoods. They collect and radiate ambient heat that warms nearby homes and gardens, even if the weather is already unpleasantly warm. Cars that park on pavement without shade are vulnerable to the most heat, which accelerates weathering.

It is an unfortunate waste. Sunshine that is useless and undesirable on streets would be useful within gardens. Although sunlight is not transferable from one situation to another, it might be partially abatable with shade. Streets are certainly no place for gardening; but the space above them may have potential to accommodate the canopies of shade trees.

Street trees are simply trees that flank streets and other roadways. Most are shady. A few are merely visually appealing. They may inhabit parkstrips, treewells or gardens that are adjacent to sidewalks. Many municipalities prescribe street trees for most of their streets. Conforming street trees are standard accessories for streets within new residential tracts.

Of course, street trees must be appropriate to their particular applications. They must get tall enough for clearance above the largest of vehicles that use the roadways below. For commercial districts, some must also stay above storefront signs. Contrarily, a few street trees must stay below aerial utilities. Street lamps, high or low, require clearance as well.

Size and form are not the only considerations. Roots of street trees must be complaisant with infrastructure. Mess should be as minimal as practical. The most complaisant street trees might stay too small to attain adequate clearance or provide much shade. The most visually appealing might be too messy. Selection of appropriate street trees necessitates significant research regarding every potential option.

Six on Saturday: Brent’s Pointless Pictures III – Watts Towers

Only two or perhaps three of these six pictures were taken in Watts. Furthermore, those towers in the backgrounds of pictures #3 and #4, although only a few blocks west of the Watts Towers, and supporting massive volumes of wattage, are merely electricity pylons. It is unimportant. Actually, these five images and one video are assembled together here only so that I need not discard them unused. Brent will not stop sending them. Now that these are the last for the moment, I can post more interesting or at least relevant images next week. I must share pictures of the esperanza and poinciana seed getting sown. Also, we moved a Mediterranean fan palm.

1. Brent can not stop taking selfies. Carly Simon sang about this sort of behavior in 1972; ‘You’re so vain.’ Here, he wants to be seen in a hard hat like my arborist colleagues wear. 

2. Old sycamores that Brent saved from certain doom are a much more important topic. Developers who want them out of their way said that the bare deciduous trees had died.

3. Tristania laurina is an exemplary small street tree for many of the narrow streets that Brent installs street trees on. This matured crop are exemplary #5 (5 gallon) specimens.

4. Minor lower growth that got pruned away promoted caliper growth. Those are not the Watts Towers, although they are only a few blocks to the west, and support many watts.

5. Brent wants to show off a new publication that features his home garden, or his work, or some such nonsense. I did not write the particular article, so it must not be very good. 

6. Brent’s home garden is SO crowded with SO much vegetation and other ‘stuff’. What a mess! It could be a hazardous situation during an earthquake. This one was very minor.

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/

Chinese Pistache

Chinese pistache colors with minimal chill.

Those who crave fall color in mild climates should appreciate Chinese pistache, Pistacia chinensis. It is happy to provide fiery yellow, orange and red color in response to a slight chill. Actually, it retains its colorful foliage later into the season with mild chill than it does with frosty weather. Rain eventually dislodges all of its deciduous foliage through winter.

Because it is so resilient to harsh situations, Chinese pistache is popular as a street tree. Pruning is necessary to establish adequate clearance of broad limbs over roadways and sidewalks. Since roots can be shallow with regular watering, root barriers should protect nearby pavement. However, established trees do not need regular watering, if any at all.

Old Chinese pistache trees, as well as those that grow wild from seed, are either male or female. Female trees produce tiny but annoyingly abundant fruit. Modern cultivars are all male, and therefore fruitless. They may get more than forty feet tall, with broad canopies. The pinnately compound leaves are just about eight inches long.

Six on Saturday: Friends

Brent, my colleague down south, plants street trees. He has been doing so for decades. Some of the older trees are quite mature now. Brent telephones me to tell me whenever the first trees on opposite sides of a street meet in the middle. It is like a graduation for that particular colony of trees. The various species mature at different rates, so they ‘meet’ over their particular street on their own distinct schedule. Brent watches them all, and attends all of their ‘graduations’. Anyway, that is what the first picture reminded me of.

1. Redwoods meeting friends over a road is not uncommon here. For compact street trees that got planted at the same time on opposite sides of an urban street, it is an indication of maturity.

2. Shasta daisies are not exactly friends. They are just two of many separate flowers on the same mature plant. They are composite flowers, so each one contains many tiny but distinct flowers.

3. Lily of the Nile, while piled with many friends, waiting to get groomed and moved to another garden, looks like Sigmund the Sea Monster should stay away from the Pacific Coast Highway.

4. Deodar cedar seedlings that grew where they could not live in an industrial yard were relocated to be with friends in a landscape a few years ago. Some, although not all, are now doing well.

5. Beau, the 1967 C10, has a friend also, named Bo, and he is a 1967 C20. Beau helped me bring so much of my old plant material from the Santa Clara Valley. Bo does not get around so much.

6. Rhody is man’s best friend. Like all of his colleagues, he is very committed to his career, which is, of course, his commitment to his colleagues. In this picture, he happily awaits their arrival.

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/

Fern Pine

Narrow leaves resemble pine needles.

It is neither a fern nor a pine. Fern pine, Podocarpus gracilior, can be a tree taller than fifty feet, and half as broad, but is often a shorn shrub or hedge that can be kept less than eight feet tall. Stems are limber enough while  young to be espaliered. The finely textured evergreen foliage is somewhat yellowish out in full sun, and darker green in partial shade. Individual leaves are as long as two and a half inches, and less than a quarter inch wide, and hang almost like fat pine needles. Some but not all mature trees can drop a bit of messy fruit with hard pits that are a bit larger than those of cherries. Bark gets distinctively blotched as it ages. The deep roots can be remarkably complaisant with concrete. Outer growth can get damaged by the harshest frosts every few winters or so, or roasted by hot dry heat every few summers.

Chinese Elm

Intricately blotched bark distinguishes Chinese elm.

Since the Dutch Elm Disease (DED) epidemic that killed so many old and stately American elm trees so many years ago, the old fashioned Chinese elm, Ulmus parvifolia, has been unavailable in nurseries. That is why there are only old and middle aged trees, and maybe a few feral seed grown trees. Chinese elm is not bothered much by the disease, but is a vector. ‘Drake’ is a modern DED resistant cultivar, but it has a very different personality, with a more upright and symmetrical structure.

The elegantly lanky trunk and main limbs can be quite curvacious, with distinctively blotched gray and tan bark. The deciduous foliage can be messy in autumn as it falls slowly and may linger through December. The neatly serrate leaves are only about an inch or two long, and half as wide. Mature trees can be more than fifty feet tall.

Norway Maple

Few maples perform as well here.

Japanese maples get all the notoriety. They have such delightful texture and form. Many are proportionate to small spaces, such as atriums. Realistically though, they are overrated and overused. Meanwhile, other maples that work as larger shade trees remain obscure. Norway maple, Acer platanoides, gets broad enough to shade much of an urban garden, but rarely gets to forty feet tall.

Of course, Norway maple has innate limitations. It dislikes arid and harshly warm desert climates. Nor does it like to be too close to the coast. Los Angeles is about as far south as it wants to live. In the Pacific Northwest, it gets much bigger, and develops greedy roots. The non-cultivar species is invasive there. Norway maple defoliates neatly for winter, but then refoliates late in about April.

Almost all local Norway maples are cultivars. ‘Schwedleri’ has richly bronzed foliage. It is rare now, but was a popular street tree in the 1950s. ‘Crimson King’ has richer purplish foliage, but is less vigorous. ‘Drummondii’ displays delightful variegation. The deciduous foliage of Norway maple turns soft brownish yellow or gold for autumn. The palmately lobed leaves may be five inches wide.

Horridculture – Vandalism

This would have been an ideal time for a seasonal update on the little Memorial Tree in Felton Covered Bridge Park. Until recently, it had been healthier and growing more vigorously than it had since it was installed a few years ago. It had survived major accidental damage, and was just beginning to thrive. Sadly […]

https://feltonleague.com/2020/06/28/vandalism/

via Vandalism — Felton League

Riots

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This is one of the several Canary Island date palms that Brent Green saved from poachers on the embankment of the Santa Monica Freeway.

Since I began posting my gardening column articles here, and supplementing with blog posts, I have deviated from horticultural topics only a few times. I will now do it again. I had earlier selected a horticultural topic for this post. It will wait for now.

Brent Green, my colleague down south, called me on the telephone to tell me to watch the news. I did so, but only briefly. It was just too crazy. So far, I have made a point of saying nothing about Coronavirus. I said nothing about those who protest the violation of their right to spread disease that will kill others. I mentioned nothing about the racist murderers in Minneapolis.

Now I see that people are senselessly rioting and looting in several cities in America.

The office building of the Canyon News, one of the newspapers that I write for, was clearly visible in the background as police helicopters showed looting of stores on the historic Rodeo Drive in Downtown Beverly Hills, in the region of Los Angeles. Police cars and palm trees were burning. From three hundred and fifty miles away, I can see it online.

This is not demonstration or protest. It is looting. It is mere opportunistic thievery. Those involved are not at all concerned about social justice, their own Communities, or that Black Lives Matter. They are exploiting an already bad situation to plunder what they can get away with.

This is happening in the Community where Brent Green has been planting his Birthday Trees (in quantities that corresponds to his age at the time) in public spaces for the past twenty two years. This is near where Brent Green saved several Canary Island date palms on the Santa Monica Freeway from poachers. This is a region that many people care about.

Streets Are Cooler With Shade

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Parked cars stay cooler in shade.

There really is no such thing as a perfect tree. Some are not quite as messy as others. Some have better structural integrity than others. Some have gentle roots; and some stay proportionate to tight spots. However, without exception, all trees grow, drop leaves, and disperse roots.

This is an important consideration when selecting any tree, and especially when selecting a street tree for the narrow space between the curb and the sidewalk (which is commonly known as a park strip). Even where there is no sidewalk, or where the sidewalk is at the curb, most of the obstacles are the same.

Street trees should have reasonably complaisant roots that should not be likely to damage curbs, sidewalks or roadways, at least for several years. They should naturally develop reasonably high branches. They will need to be pruned higher than trucks that may park at the curb. Street trees must also tolerate harsh exposure.

Wider park strips can of course accommodate larger trees. Those that are only two feet wide or narrower are probably not wide enough for any tree larger than photinia, purple-leaf plum or English hawthorn, which are difficult to prune for clearance over roadways and sidewalks.

Messy leaves, flowers or fruit that might not be a problem within the garden might be more of a problem at the curb. It is not so easy to rake such debris if cars park over it. Trees that are commonly infested with scale or aphid are likely to drop sticky honeydew (scale and aphid poop) onto parked cars.

Unfortunately, those who get street trees do not always get to select them. Many municipalities assign specific trees to specific streets. Some streets have a few trees to choose from. Others have only one option. Home Owners’ Associations (HOAs) decide if and where new trees get planted.

Crape myrtle is probably the most common choice for a new street tree because the roots do not get big enough to damage pavement. However, the canopies are not very big either. They stay too low to be pruned above trucks. Crape myrtle is susceptible to scale infestation that can get bad enough to make sidewalks sticky.

For many years, London plane (sycamore) had been another popular street tree. Unfortunately, the voracious roots can damage pavement within only a few years. The messy foliage discolors and starts to fall before autumn.