California Sycamore

41119Out in rural chaparral regions, where water is scarce, the big and bold California sycamore, Platanus racemosa, somehow seems to find the spots where groundwater is not too far below the surface of the soil. It is technically a riparian tree, that is just as comfortable competing with cottonwoods and willows along forested rivers and floodplains. It eventually get too big and messy for refined urban gardens, but is somewhat popular nonetheless.

The bulky trunks and limbs are just too striking to ignore, especially as trees defoliate to expose the mottled beige and gray bark. Trunks are typically leaning and irregularly sculptural. Many trees have multiple trunks. The biggest trees are a hundred feet tall. The big palmately lobed leaves can be eight inches wide, but unfortunately do not color well in autumn. The foliar tomentum (fuzz) can be irritating to the skin when leaves need to be raked. Athracnose causes much of the early spring foliage to fall, and sometimes distorts and discolors later summer foliage.

Arborists Specialize In Tree Horticulture

0

Why is it so difficult to believe that there are so many different kinds of horticultural professionals? No one is ever surprised that surgeons, cardiologists, dermatologists, ophthalmologists and pulmonologists are all physicians. Yet, those who do not know better consider all horticultural professionals to be ‘gardeners’. This is actually more insulting to real professionals than outsiders can imagine, because the gardening industry is more dominated by non-professionals than any other horticultural industry.

Nurserymen, landscapers and florists are also horticultural professionals. Each of these basic categories can be divided into more specialized professions. For example, production nurserymen grow nursery stock or other horticultural commodities, while retail nurserymen maintain plant material only long enough to sell it. Maintenance gardeners are probably the most familiar of horticultural professionals because so many of us use their services around our home gardens.

Arborists are the horticulturists who specialize in trees, and really should be more familiar than they are. The only landscapes that have no possible use for their services are those that are devoid of trees. Even the most proficient of maintenance gardeners should not be expected to maintain large trees or diagnose potential arboricultural problems, not only because arboriculture is so specialized, but also because maintenance gardeners have their own specialties to be concerned with.

Because trees are the most substantial features of a landscape, and they have the potential to cause proportionate problems if not maintained properly, it is very important to have them maintained by qualified arborists. Those who are certified by the International Society of Arboriculture, or ISA, have passed an exam of their expertise, and maintain their certification with regular involvement with the ISA. Such involvement includes attendance to arboricultural seminars and classes.

It is ironic that some of the least familiar of horticultural professionals need to stay so dedicated to the maintenance of their credentials. Certified arborists can be found at the website of the ISA at isa-arbor.com.

European White Birch

91127Like a flower girl scatters rose petals ahead of a wedding procession, European white birch, Betula pendula, tosses its small deltoid leaves soon after turning soft yellow with autumn chill. Color may not last long on the trees, but becomes a delightful mess for those who appreciate such assets. The primary allure though, is the slender strikingly white trunks, accented with black furrowing.

European white birch is very informal, but also elegant enough for formal landscapes. To best display their gently leaning white trunks, they are popularly planted in relaxed groups. Their canopies are neither broad nor dense, so a few fit together nicely. As lower branches get pruned away, pendulous upper branches sway softly in the breeze. Mature trees are mostly less than fifty feet tall.

Himalayan birch, Betula utilis or Betula jacquemontii, which has become more popular than European white birch since the 1990s, has a completely different personality. Its strictly vertical trunks and upright growth are appealing separately, but incompatible with European white birch. When adding trees to an established grove of any birch, it is very important to procure more of the same.

Keep Vegetation Clear From Chimneys

51028thumbFireplaces simply are not what they used to be. Building regulations in many municipalities do not allow for the construction of new fireplaces, except only for pellet stoves. Fireplaces that get damaged by earthquakes are commonly removed instead of repaired. Now that urban sprawl has replaced so many of the rural areas and defunct orchards, firewood is more expensive, even if purchased from a tree service. When a tree needs to be cut down, no one seems to have the time to cut and split the wood.

Modern heating systems are so much more reliable, efficient and just plain easy. Their fuel can actually be less expensive than firewood, and is not nearly as polluting. There is no smoke to offend the neighbors. There are no potentially dangerous sparks. There is no dirty chimney that needs to be cleaned. There is no need for firewood occupying space in the garden. Yet, with all the advantages of other heating systems, many of who still have fireplaces like to use them now that the weather is getting cool.

Because so much heat and a few sparks go out through the chimney, it is extremely important to keep trees and vines away from the top of the chimney. Cypress, pines, cedars, large junipers, eucalypti and fan palms that are not groomed of their dried old leaves are very combustible. Vines like wisteria, bougainvillea, creeping fig and Boston ivy are not unusually combustible, but have a sneaky way of overwhelming chimneys and accumulating debris (and sometimes rat or bird nests!). Any vegetation will be combustible if it gets hot enough. Sparks from burning foliage above can easily ignite old fashioned cedar shingles.

Trees should also be pruned away from roofs, gutters, fences and anything else that can be damaged by the abrasive motion of the stems and foliage in the wind. Stems of deciduous trees lose weight as they defoliate, and may even lift off of roofs that they had been leaning onto just a few weeks ago, but should be pruned accordingly anyway. Branches that have been leaning on a roof for quite a while may have accumulated a bit more debris than would be expected. Gutters and downspouts should be cleared of debris before the rain starts, and may need to be cleared again later where deciduous trees fill them up through autumn and winter.

Evergreen Trees Drop Leaves Too

IMG_20141004_153228As the deciduous trees that will soon be coloring for autumn defoliate for winter, the evergreen trees will become more prominent. Some evergreen trees will drop some of their foliage along with deciduous trees through autumn and winter. Many drop some of their old foliage as new foliage develops in spring, or later in summer. All are on distinct schedules, but are never completely bare.

That certainly does not mean that evergreen trees are not messy. To the contrary, some happen to be significantly messier than some deciduous trees are. They are only evergreen because they do not drop their old foliage until it is replaced by new foliage. Whether individual leaves last just slightly longer than a single year, or for several years, they eventually shed and fall to the ground.

In fact, evergreen trees may shed small but pestering volumes of foliage for a few months or even constantly throughout the year. Some deciduous trees defoliate so efficiently within a very limited time once the weather gets cool, that all of their fallen leaves will be raked away within only two or three weeks. Of course, some trees, both deciduous and evergreen, drop flowers or fruit or both.

Not only do most evergreen trees shed for a longer time than most deciduous trees do, but most shed foliage that is not so easy to rake away. Cypress shed minute and finely textured leaves that are impossible to rake from lawns, but toxic if they accumulate. Juniper and arborvitae are easier to accommodate only because the trees are smaller. Fir, spruce and cedar have bigger needles.

Broadleaf evergreen trees are very different from coniferous trees. Their leaves are considerably easier to rake. They are generally more substantial than those of deciduous trees though. Some may not decompose so readily in deep groundcover. Southern magnolia leaves are notably slow to compost. Instead of producing cones, some broadleaf trees drop acorns or other messy seed.

Nonetheless, where there are compatible with their landscapes, evergreen trees are as practical as deciduous trees are.

Six on Saturday: Tree Removal

 

The forest is constantly producing trees faster than we can cut them down. Even if we were not too busy with our many other tasks, we are not equipped to safely remove all of the large trees that become hazardous as they mature. Therefore, a crew who is so equipped is sometimes hired, and was here just this last week to remove several locusts, a few bays and a live oak.

1. The 80s are over. Someone painted this water pipe like this so that a crew cutting trees down nearby would not drop anything on it. The crew would have just put an orange cone over it.P91109

2. I was much younger and healthier back in the summer of 1988, when I did an internship with some of the most excellent arborists in the Santa Clara Valley, but I never climbed like this.P91109+

3. These trees are not much more than eighty feet tall, but needed to be parted out over those roofs. They are less than forty years old, from the 1980s or so. The arborist is in the middle.P91109++

4. Locust is unpopular firewood. These locust trees were therefore cut into logs less than seven feet (or 84 inches) long to fit into a pickup for removal, but were then instead chipped on site.P91109+++

5. This structurally deficient oak will eventually need to be removed. For now, it is groomed and lightened for winter storms. It was a nice day at the time, with temperatures in the low 80s.P91109++++

6. Mature bay trees develop distended lignotubers. The trunk of this bay tree was significantly narrower just two feet above this stump. The tree was not much more than eighty years old.P91109+++++

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/

Red Willow

P91108It is almost never planted in home gardens, but the native red willow, Salix laevigata, has a sneaky way of getting where it wants to be. The minute seeds go wherever the wind blows them. Because it is a riparian tree, red willow prefers well watered spots. If not detected and pulled up in the first year, it can grow rather aggressively, and overwhelm more desirable plants, although the somewhat sparse canopy makes only moderate shade.

With a bit of grooming, red willow can be a handsomely asymmetrical tree, with upright branch structure. However, even the healthiest trees rarely get more than thirty feet tall, or much more than forty years old. The leaves are a bit shorter and wider than those of the more familiar weeping willow, and do not color as well in autumn. There are actually a few other native willows that are also commonly know as red willow. Some are quite similar, while others are very different.P91108+

Leyland Cypress

91113The ‘X’ preceding its Latin name ‘X Cupressocyparis leylanii‘ designates Leyland cypress as a hybrid of two distinct genera, namely Monterey cypress and Nootka cypress. (Those who consider the parents to be two species of the same genus know Leyland cypress as Cupressus X leylandii.) The many cultivars combine desirable qualities of both parents, but also innate weaknesses.

Rows of Leyland cypress grow fast to become densely evergreen windbreaks or informal screens within only a few years. However, they are very susceptible to cypress canker, and are likely to succumb within twenty five years or so. Farther inland, they may not last half as long. That may be quite acceptable for temporary windbreaks in front of slower but more permanent shrubby trees.

Common Leyland cypress develops a distinctly plump but conical form, with slightly grayish foliage. Most other cultivars are more columnar. Foliar color ranges from bluish green to gold. The tiny scale leaves are densely set in flat sprays. Healthy trees can get nearly thirty feet tall in ten years. Most stay lower where exposed. Crowded trees that live long enough exceed a hundred feet tall.

X Marks The Spot

P91102KHorticulture is not all about growing things. If everyone was out planting trees, the World would eventually be overwhelmed with forest. It is sometimes necessary to cut trees down. There are several at work that we have been wanting to cut down for quite a while. Some are structurally deficient enough to eventually become hazardous, which is unacceptable in public spaces.

Even here among some of the oldest trees in the World, nothing last forever. Coast live oak, like that in the picture above, has potential to survive for centuries, but eventually succumbs to decay and disease. If fact, this particular specimen is doing it right now. If not cut down soon, it will eventually fall onto an adjacent building and a parking lot below. Its days are numbered.

Literally, it will be cut down on Monday morning, along with a few other coast live oaks and bay laurels in the neighborhood. The orange ‘X’ on the trunk is so faded from the delay of getting this done, that is it barely discernible. (Actually, the can of spray paint was empty.) The trunk and even the main limbs are so rotten that there will not be much firewood left to cut and split.

Cutting this tree down may seem to be unnatural, but so was pruning it for decades so that it would not fall down. It is impossible to say what situation this tree would be in now without past or present intervention. I am more concerned with how it and other trees interact with their surroundings, and the safety of everyone involved. We can not always let nature do as it pleases.

Forest fires are very natural components to our local ecosystems, but because so many of us live here, significant effort and resources are expended on containment!

Weeping White Spruce

41029As the colorful deciduous trees go bare, the evergreen trees get more attention. A weeping white spruce, Picea glauca ‘Pendula’, really stands out. It grows slowly to only about fifteen feet tall and maybe five feet wide, so does not need as much space as a typical spruce tree. What makes it so distinctive is the weirdly pendulous stems that hang limply from a strictly vertical trunk. It is hard to believe that it is only a different variety of the same species as the dwarf Alberta spruce, which is very short, dense and symmetrically conical, with stout little stems. The foliage of weeping white spruce is lighter green than that of most other spruces, but is not as blue as that of blue spruce. The short and stiff needles are rather prickly to handle.

The narrow and weirdly sculptural form of the weeping white spruce is no good as a shade tree, but is an excellent trophy tree for a prominent spot. Full sun is best. A bit of shade can cause the main trunk to lean toward sunlight. Young trees should only be staked if they need it, since they can become dependent on stakes. The lowest limbs can be allowed to creep over the ground.